CN103517506A - Driving circuit and method for providing power to led light source, and power converter - Google Patents
Driving circuit and method for providing power to led light source, and power converter Download PDFInfo
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- CN103517506A CN103517506A CN201210361522.5A CN201210361522A CN103517506A CN 103517506 A CN103517506 A CN 103517506A CN 201210361522 A CN201210361522 A CN 201210361522A CN 103517506 A CN103517506 A CN 103517506A
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- 238000004804 winding Methods 0.000 claims description 27
- 230000008878 coupling Effects 0.000 claims description 21
- 238000010168 coupling process Methods 0.000 claims description 21
- 238000005859 coupling reaction Methods 0.000 claims description 21
- 238000012544 monitoring process Methods 0.000 claims description 16
- 238000001914 filtration Methods 0.000 claims description 6
- 230000001965 increasing effect Effects 0.000 claims description 6
- 230000003247 decreasing effect Effects 0.000 claims description 4
- 230000009467 reduction Effects 0.000 claims description 2
- 230000007423 decrease Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 20
- 238000004146 energy storage Methods 0.000 description 14
- 230000001052 transient effect Effects 0.000 description 5
- 238000007600 charging Methods 0.000 description 4
- 230000004044 response Effects 0.000 description 4
- 239000003990 capacitor Substances 0.000 description 3
- 230000033228 biological regulation Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 208000001953 Hypotension Diseases 0.000 description 1
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- 238000006243 chemical reaction Methods 0.000 description 1
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/37—Converter circuits
- H05B45/3725—Switched mode power supply [SMPS]
- H05B45/385—Switched mode power supply [SMPS] using flyback topology
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/37—Converter circuits
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/37—Converter circuits
- H05B45/3725—Switched mode power supply [SMPS]
- H05B45/375—Switched mode power supply [SMPS] using buck topology
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
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Abstract
The invention provides a driving circuit and method for providing power to an LED light source, and a power converter. The driving circuit comprises a voltage filter, a transformer and a controller. The voltage filter receives and filters an input voltage to provide a stable voltage. The transformer converts the stable voltage into an output voltage to provide power to a light source. The controller generates a driving signal to make a switch work alternatively between a first state and a second state. The controller controls time durations of the first state and the second state, such that an input current decreases to a predetermined level during the second state and increases to a peak level proportional to the input voltage during the first state. The controller controls the ratio of time in the first state to time in the second state to adjust an output current flowing through the light source to a target level. According to the invention, the current control precision is improved, power factors of the driving circuit are corrected, the quality of power supply is improved, and line frequency interference of lighting of the light source is minimized.
Description
Technical field
The present invention relates to a kind of drive circuit, relate in particular to a kind of drive circuit for LED source power supply and method, power converter.
Background technology
Figure 1 shows that a kind of block diagram of traditional light source driving circuit 100.This drive circuit 100 for driving light source as light-emitting diode chain 108.Power supply 102 provides input voltage V
iNfor drive circuit 100 power supplies.Drive circuit 100 comprises buck converter, this buck converter under the control of controller 104 for light-emitting diode chain 108 provides the VOUT of the voltage after conversion.This buck converter comprises diode 114, inductance 112, electric capacity 116 and switch 106.Resistance 110 is connected with switch 106.When switch 106 is connected, resistance 110 and inductance 112 and 108 couplings of light-emitting diode chain, the feedback signal of the electric current of the inductance 112 of flowing through is indicated in generation.When switch 106 disconnects, resistance 110 disconnects with inductance 112 and light-emitting diode chain 108, thereby there is no the electric current resistance 110 of flowing through.
Summary of the invention
The invention provides a kind of drive circuit, power converter and method for LED source power supply, to improve the accuracy of this drive circuit output current, the line frequency that reduces light source luminescent disturbs.
The invention provides a kind of drive circuit for LED source power supply, described drive circuit comprises:
Voltage filter, for receiving input voltage and filtering described input voltage, so that burning voltage to be provided;
Be coupled in the transformer of described voltage filter, for described burning voltage is converted to output voltage, think described LED source power supply; And
Be coupled in the switch of described voltage filter and described transformer;
Be coupled in the controller of described switch, for generation of driving signal so that described switch alternation in the first state and the second state, when described switch is during in described the first state, the input current of described voltage filter of flowing through increases, when described switch is during in described the second state, described input current reduces
Wherein, described controller is controlled the duration of described the first state, so that described input current increases to and the proportional peak value of described input voltage from preset value in described the first state, control the duration of described the second state, so that described input current is decreased to described preset value in described the second state, described controller is also controlled the ratio between the duration of described the first state and the duration of described the second state, with what regulate the described LED source of flowing through, outputs current to target current value.
The present invention also provides a kind of power converter for LED source power supply, and described power converter comprises:
Switch, for according to pulse signal alternation at the first state and the second state;
Voltage filter with described switch coupling, described voltage filter comprises: inductance and electric capacity, described voltage filter filters input voltage so that burning voltage to be provided, wherein, when described switch is during in described the first state, input current flow through described inductance and described switch, described input current increases to and the proportional peak value of described input voltage from preset value; When described switch is during in described the second state, described input current flow through described inductance and described electric capacity, described input current is reduced to described preset value; And
Transformer, described transformer comprises: the armature winding and the secondary winding that are coupled in described switch, described transformer is converted to output voltage by described burning voltage, think described LED source power supply, wherein, when described switch is during in described the first state, described transformer is powered by described burning voltage, and the electric current of flow through described armature winding and described switch increases; When described switch is during in described the second state, thereby be described LED source, the electric discharge of described transformer powers, the electric current of the described secondary winding of flowing through reduces,
Wherein, by controlling the duty ratio of described pulse signal, with what regulate the described LED source of flowing through, output current to target current value.
It is a kind of for LED source provides the method for electric energy that the present invention also provides, and described method comprises:
Receive input voltage and input current; Filter described input voltage, so that burning voltage to be provided;
Described burning voltage is converted to output voltage, thinks described LED source power supply;
Produce to drive signal, so that switch alternation is in the first state and the second state, wherein, in described the first state, described input current increases, and in described the second state, described input current reduces;
Control the duration of described the first state, described input current is increased to and the proportional peak value of described input voltage from preset value in described the first state, control the duration of described the second state, make described input current be reduced to described preset value in described the second state; And
Control the ratio between the described duration of described the first state and the described duration of described the second state, with what regulate the described LED source of flowing through, output current to target current value.
Compared with prior art, the embodiment of the present invention can be by the current stabilization of the LED source of flowing through in target current value, improved Current Control precision, also proofreaied and correct the power factor of drive circuit, thereby improved the power supply quality of circuit, and this circuit reduces or eliminated the ripple of the output current of the light source of flowing through that the variation by input voltage causes, thereby the line frequency that has further reduced light source luminescent disturbs.
Accompanying drawing explanation
Below, by the description in conjunction with its accompanying drawing to some embodiments of the present invention, can further understand object of the present invention, specific structural features and advantage.
Figure 1 shows that a kind of block diagram of conventional light source drive circuit;
Figure 2 shows that the block diagram of light source driving circuit according to an embodiment of the invention;
Figure 3 shows that the circuit diagram of light source driving circuit according to an embodiment of the invention;
Figure 4 shows that the structural representation of Fig. 3 middle controller;
Figure 5 shows that the oscillogram of Fig. 4 middle controller;
Figure 6 shows that the another kind of structural representation of Fig. 3 middle controller;
Figure 7 shows that the signal waveforms that Fig. 6 middle controller generates or receives;
Figure 8 shows that the circuit diagram of light source driving circuit in accordance with another embodiment of the present invention;
Fig. 9 A is depicted as the block diagram of light source driving circuit in accordance with another embodiment of the present invention;
Fig. 9 B is depicted as the signal waveforms that in Fig. 9 A, drive circuit generates or receives;
Figure 10 shows that the circuit diagram of the light source driving circuit of another embodiment according to the present invention;
Figure 11 shows that the structural representation of Fig. 9 A middle controller;
Figure 12 shows that the signal waveforms that light source driving circuit generates or receives according to an embodiment of the invention;
Figure 13 shows that the method flow diagram that drives according to an embodiment of the invention load;
Figure 14 A is depicted as the block diagram of light source driving circuit in accordance with another embodiment of the present invention;
Figure 14 B is depicted as the signal waveforms that in Figure 14 A, light source driving circuit generates or receives;
Figure 15 shows that the circuit diagram of light source driving circuit in Figure 14 A;
Figure 16 shows that the structural representation of Figure 14 A middle controller;
Figure 17 shows that the method flow diagram of driving light source in accordance with another embodiment of the present invention.
Embodiment
To embodiments of the invention be provided to detailed explanation below.Although the present invention is set forth and illustrated by these execution modes, it should be noted that the present invention is not merely confined to these execution modes.On the contrary, all substitutes, variant and the equivalent in the defined invention spirit of appended claim and invention scope contained in the present invention.
In addition, for better explanation the present invention, in embodiment below, provided numerous details.It will be understood by those skilled in the art that and there is no these details, the present invention can implement equally.In other example, the method for knowing for everybody, flow process, element and circuit are not described in detail, so that highlight purport of the present invention.
The invention provides a kind of for example, circuit and method so that various loads (, light source) are powered of control power converter.This circuit comprises for example, the current monitor through the electric current of energy-storage units (, inductance) for monitoring stream, and controller.This controller is for controlling the switch with described inductance coupling high, thereby the average current of the described light source that makes to flow through equals target current value.No matter this switch connection or disconnection, the equal energy of this current monitor monitoring stream is through the electric current of described inductance.
Figure 2 shows that the block diagram of light source driving circuit 200 according to an embodiment of the invention.Light source driving circuit 200 comprises rectifier 204.Rectifier 204 receives from the input voltage of power supply 202 and for power converter 206 voltage after adjustment is provided.Power converter 206 receives voltage after adjusting and provides output power for load 208.Power converter 206 can be buck converter or booster converter.In one embodiment, power converter 206 comprises energy-storage units 214 and for the current monitor 218(that monitors energy-storage units 214 situations for example, a resistance).Current monitor 218 provides first signal ISEN for controller 210.This first signal ISEN indicates the transient current of the energy-storage units 214 of flowing through.Light source driving circuit 200 also comprises filter 212, for producing secondary signal IAVG according to first signal ISEN.Secondary signal IAVG indicates the average current of the energy-storage units 214 of flowing through.In one embodiment, controller 210 receives first signal ISEN and secondary signal IAVG, and controls the average current of the energy-storage units 214 of flowing through, and this average current is equated with target current value.
Figure 3 shows that the circuit diagram of light source driving circuit 300 according to an embodiment of the invention.In Fig. 3, number identical parts with Fig. 2 and there is similar function.In the embodiment shown in fig. 3, light source driving circuit 300 comprises rectifier 204, power converter 206, filter 212 and controller 210.Rectifier 204 can be the bridge rectifier that comprises diode D1, D2, D3, D4.The voltage that rectifier 204 is adjusted from power supply 202.Power converter 206 receives the voltage after the adjustment of rectifiers 204 outputs and produces output power is load (as light-emitting diode chain 208) power supply.
In the embodiment shown in fig. 3, power converter 206 can be specifically buck converter.This buck converter comprises: electric capacity 308, switch 316, diode 314, this current monitor of current monitor 218(can be for example resistance), the inductance 302 intercoupling and inductance 304 and electric capacity 324.Diode 314 is between switch 316 and the ground of light source driving circuit 300.Electric capacity 324 is in parallel with light-emitting diode chain 208.In one embodiment, inductance 302 and inductance 304 electromagnetic coupled each other.Inductance 302 and inductance 304 are all connected to a common node 333.In the embodiment shown in fig. 3, common node 333 is between resistance 218 and inductance 302.Yet, it will be appreciated by persons skilled in the art that the present invention is not limited to this structure, common node 333 also can be between switch 316 and resistance 218.Common node 333 for controller 210 provide with reference to ground.In one embodiment, the reference ground of controller 210 is different with the ground of light source driving circuit 300.By switching on and off switch 316, the electric current of the inductance 302 of flowing through can be adjusted, thereby regulates the electric power of light-emitting diode chain 208.The situation of inductance 304 monitoring inductance 302, for example, whether monitoring stream is reduced to default current value through the electric current of inductance 302.
In embodiment illustrated in fig. 3, the port of controller 210 comprises ZCD, GND, DRV, VDD, CS, COMP and FB.Wherein, 304 couplings of port ZCD and inductance, for example, for receiving the monitor signal AUX of indication inductance 302 situations (, flow through the electric current of inductance 302 whether be reduced to default current value " 0 ").Monitor signal AUX also can indication light diode chain 208 whether in open-circuit condition.Port DRV and switch 316 are coupled and produce and drive signal (as pulse width modulating signal PWM1) to be switched on or switched off switch 316.Port VDD and inductance 304 are coupled and receive the electric power of self-inductance 304.Port CS and resistance 218 are coupled and receive the flow through first signal ISEN of transient current of inductance 302 of indication.Port COMP is coupled by electric capacity 318 and the reference ground of controller 210.Port FB be coupled by filter 212 and resistance 218 and receives the secondary signal IAVG of the average current of indicating the inductance 302 of flowing through.In the embodiment shown in fig. 3, port GND(is also the reference ground of controller 210) be connected to the common node 333 between resistance 218, inductance 302, inductance 304.
When switch 316 is connected, electric current switch 316, resistance 218, inductance 302, light-emitting diode chain 208 ground to light source driving circuit 300 of flowing through.When switch 316 disconnects, electric current flow through resistance 218, inductance 302, light-emitting diode chain 208 and diode 314.Inductance 304 and inductance 302 couplings and can monitor the situation of inductance 302, for example, whether monitoring stream is reduced to predetermined current value through the electric current of inductance 302.Controller 210 is the electric current through inductance 302 according to signal AUX, ISEN and IAVG monitoring stream, and by pulse width modulating signal PWM1 control switch 316, and the average current of the inductance 302 that makes to flow through equals predetermined current value.So after electric capacity 324 filtering, the electric current of the light-emitting diode chain 208 of flowing through also equals predetermined current value.
In one embodiment, controller 210 judges that according to monitor signal AUX whether light-emitting diode chain 208 is in open-circuit condition.If light-emitting diode chain 208 open circuits, the voltage on electric capacity 324 increases.When switch 316 is during in off-state, the voltage at inductance 302 two ends increases, and the voltage of monitor signal AUX also increases thereupon.Consequently, the electric current by port ZCD ramp metering device 210 increases.Therefore, controller 210 monitor signal AUX, when switch 316 during in off-state and the electric current of ramp metering device 210 surpass a threshold value, controller 210 judgement light-emitting diode chains 208 are in open-circuit condition.
Figure 4 shows that the structural representation of Fig. 3 middle controller 210.Figure 5 shows that the oscillogram of Fig. 4 middle controller 210.Fig. 4 is described in connection with Fig. 3 and Fig. 5.
In the embodiment shown in fig. 4, controller 210 comprises: error amplifier 402, comparator 404 and pulse width modulating signal generator 408.Error amplifier 402 produces error signal VEA according to the voltage difference between reference signal SET and secondary signal IAVG.Reference signal SET indicating target current value.Error amplifier 402 receives secondary signal IAVG by port FB, and secondary signal IAVG indicates the average current of the inductance 302 of flowing through.Error signal VEA can adjust to the average current of the inductance 302 of flowing through to equal target current value.Comparator 404 and error amplifier 402 couplings, compare error signal VEA and first signal ISEN.Comparator 404 receives first signal ISEN by port CS, and first signal ISEN indicates the transient current of the inductance 302 of flowing through.Pulse width modulating signal generator 408 receives monitor signal AUX by port ZCD, and monitor signal AUX indicates the electric current of the inductance 302 of flowing through whether to be reduced to predetermined current value (being for example reduced to 0).Pulse width modulating signal generator 408 and comparator 404 and port ZCD coupling, produce pulse width modulating signal PWM1 according to the output of comparator 404 and monitor signal AUX.Pulse width modulating signal PWM1 is by the conducting state of port DRV control switch 316.
The pulse width modulating signal PWM1 that 408 generations of pulse width modulating signal generator have the first state (as logical one) is with turn on-switch 316.When switch 316 is connected, electric current switch 316, resistance 218, inductance 302, light-emitting diode chain 208 ground to light source driving circuit 300 of flowing through.The electric current of inductance 302 of flowing through increases gradually, and the voltage of first signal ISEN is increased gradually.In one embodiment, when switch 316 is connected, the voltage of monitor signal AUX is negative value.In controller 210 inside, comparator 404 compares error signal VEA and first signal ISEN.When the voltage of first signal ISEN surpasses the voltage of error signal VEA, comparator 404 is output as logical zero, otherwise comparator 404 is output as logical one.In other words, the output of comparator 404 comprises a series of pulse.In response to the trailing edge of comparator 404 outputs, the pulse width modulating signal PWM1 that 408 generations of pulse width modulating signal generator have the second state (as logical zero) is with cut-off switch 316.When switch 316 disconnects, the voltage of monitor signal AUX become on the occasion of.When switch 316 disconnects, electric current flow through resistance 218, inductance 302, light-emitting diode chain 208 and diode 314.The electric current of inductance 302 of flowing through reduces gradually, so the voltage of first signal ISEN reduces gradually.When the electric current of the inductance 302 of flowing through is reduced to predetermined current value (as being reduced to 0), the voltage of monitor signal AUX can produce a trailing edge.Under the effect of monitor signal AUX trailing edge, the pulse width modulating signal PWM1 that 408 generations of pulse width modulating signal generator have the first state (as logical one) is with turn on-switch 316.
In one embodiment, the duty ratio of pulse width modulating signal PWM1 is determined by error signal VEA.If the voltage of secondary signal IAVG is less than the voltage of reference signal SET, the voltage that error amplifier 402 increases error signal VEA is to increase the duty ratio of pulse width modulating signal PWM1, accordingly, the average current of inductance 302 of flowing through increases, until the voltage of secondary signal IAVG increases to the voltage of reference signal SET.If the voltage of secondary signal IAVG is greater than the voltage of reference signal SET, the voltage that error amplifier 402 reduces error signal VEA is to reduce the duty ratio of pulse width modulating signal PWM1, accordingly, the average current of inductance 302 of flowing through reduces, until the voltage of secondary signal IAVG is reduced to the voltage of reference signal SET.Like this, the flow through average current of inductance 302 can be adjusted to target current value and substantially equates.
Figure 6 shows that the another kind of structural representation of Fig. 3 middle controller 210.Figure 7 shows that the oscillogram of Fig. 6 middle controller 210.Fig. 6 is described in connection with Fig. 3 and Fig. 7.
In the embodiment shown in fig. 6, controller 210 comprises: error amplifier 602, comparator 604, sawtooth signal generator 606, reset signal generator 608 and pulse width modulating signal generator 610.Error amplifier 602 produces error signal VEA according to the voltage difference between reference signal SET and secondary signal IAVG.Reference signal SET indicating target current value.Error amplifier 602 receives secondary signal IAVG by port FB, and secondary signal IAVG indicates the average current of the inductance 302 of flowing through.Error signal VEA is for adjusting the average current of the inductance 302 of flowing through so that this average current equals target current value.Sawtooth signal generator 606 produces sawtooth signal SAW.Comparator 604 and error amplifier 602 and 606 couplings of sawtooth signal generator, and error signal VEA and sawtooth signal SAW are compared.Reset signal generator 608 produces reset signal RESET.Reset signal RESET acts on sawtooth signal generator 606 and pulse width modulating signal generator 610.In response to reset signal RESET, switch 316 is connected.Pulse width modulating signal generator 610 and comparator 604 and reset signal generator 608 couplings, and produce pulse width modulating signal PWM1 according to the output of comparator 604 and reset signal RESET.Pulse width modulating signal PWM1 is by the conducting state of port DRV control switch 316.
In one embodiment, reset signal RESET is the pulse signal with fixed frequency.In another embodiment, reset signal RESET makes the pulse signal that the time of switch 316 in off-state is constant.For example, in Fig. 7, it is that time of logical zero is constant T that reset signal RESET makes pulse width modulating signal PWM1
oFF.
In response to the pulse of reset signal RESET, the pulse width modulating signal PWM1 that 610 generations of pulse width modulating signal generator have the first state (as logical one) is with turn on-switch 316.When switch 316 is connected, electric current switch 316, resistance 218, inductance 302, light-emitting diode chain 208 ground to light source driving circuit 300 of flowing through.In response to the pulse of reset signal RESET, the voltage of the sawtooth signal SAW that sawtooth signal generator 606 produces starts to increase from initial value INI.When the voltage of sawtooth signal SAW increases to the voltage of error signal VEA, the pulse width modulating signal PWM1 that 610 generations of pulse width modulating signal generator have the second state (as logical zero) is with cut-off switch 316, and the voltage of sawtooth signal SAW is reset to initial value INI.Until the next pulse of reset signal RESET is when arrive, the voltage of sawtooth signal SAW just starts again to increase from initial value INI.
In one embodiment, the duty ratio of pulse width modulating signal PWM1 is determined by error signal VEA.If the voltage of secondary signal IAVG is less than the voltage of reference signal SET, the voltage that error amplifier 602 increases error signal VEA is to increase the duty ratio of pulse width modulating signal PWM1, accordingly, the average current of inductance 302 of flowing through increases, until the voltage of secondary signal IAVG increases to the voltage of reference signal SET.If the voltage of secondary signal IAVG is greater than the voltage of reference signal SET, the voltage that error amplifier 602 reduces error signal VEA is to reduce the duty ratio of pulse width modulating signal PWM1, accordingly, the average current of inductance 302 of flowing through reduces, until the voltage of secondary signal IAVG is reduced to the voltage of reference signal SET.Like this, the flow through average current of inductance 302 can be adjusted to target current value and substantially equates.
Figure 8 shows that the circuit diagram of light source driving circuit light source driving circuit 800 in accordance with another embodiment of the present invention.In Fig. 8, number identical parts with Fig. 2, Fig. 3 and there is similar function.
The port VDD of controller 210 is by switch 804 and rectifier 204 couplings, for receiving the voltage of rectifier 204 outputs.At switch 804 and controller 210, with reference to the Zener diode 802 between ground, keep the voltage substantially constant of port VDD.In embodiment illustrated in fig. 8, the port ZCD of controller 210 and inductance 302 electric coupling, receive the monitor signal AUX that indicates inductance 302 situations.Monitor signal AUX can indicate the electric current of the inductance 302 of flowing through whether to be reduced to predetermined current value (for example, whether being reduced to 0).Common node 333 for controller 210 provide with reference to ground.
In sum, the invention provides a kind of power converter of controlling with the circuit to load supplying.In one embodiment, power converter is that load (for example, light-emitting diode chain) provides direct current.In another embodiment, power converter provides the charging current of direct current for battery.Compare with the traditional circuit in Fig. 1, the electric current that circuit of the present invention offers load or battery can obtain controlling more accurately.And circuit of the present invention goes for having the voltage source of high voltage.
Fig. 9 A is depicted as the block diagram of light source driving circuit 900 in accordance with another embodiment of the present invention.In Fig. 9 A, number identical parts with Fig. 2, Fig. 3 and there is similar function.In one embodiment, light source driving circuit 900 comprises: with filter 920, rectifier 204, power converter 906, load 208, sawtooth signal generator 902 and the controller 910 of power supply 202 couplings.Power supply 202 produces AC-input voltage V
aC(for example, V
aCthere is sine wave signal) with exchange input current I
aC.Exchange input current I
aCflow into filter 920.Electric current I
aC' from filter 920, flow out, and flow into rectifier 204.Rectifier 204 receives AC-input voltage V by filter 920
aC, and commutating voltage V is provided on power line 912
iNwith rectified current I
iN.Power line 912 is coupled between rectifier 204 and power converter 906.Power converter 906 is by commutating voltage V
iNconvert output voltage V to
oUT, for load 208 provides electric energy.Controller 910 and power converter 906 couplings, for controlling power converter 906, to regulate the electric current I that flows through load 208
oUT, and the power factor of proofreading and correct drive circuit 900.
In one embodiment, according to driving signal 962, generate sawtooth signals 960 with the sawtooth signal generator 902 of controller 910 couplings.For example, driving signal 962 can be pulse width modulating signal.In one embodiment, when driving signal 962 to be logic high, sawtooth signal 960 increases; When driving signal 962 to be logic low, sawtooth signal 960 is reduced to predeterminated voltage value (for example, being reduced to 0V).
Advantageously, controller 910 produces driving signal 962 according to sawtooth signal 960 and secondary signal IAVG.Drive signal 962 control switchs 316, the electric current I of the load 208 that makes to flow through
oUTremain on target current value, to improve the accuracy of Current Control.In addition, drive signal 962 control switchs 316, regulate rectified current I
iNaverage current I
iN_AVGwith commutating voltage V
iNsubstantially homophase, to proofread and correct the power factor of drive circuit 900.It will be appreciated by persons skilled in the art that " homophase substantially " described in the embodiment of the present invention refers to two waveforms same-phase in theory, yet in actual applications, due to the existence of electric capacity in circuit, cause two waveforms to have trickle differing.The operation principle of drive circuit 900 will further describe in Fig. 9 B.
Fig. 9 B is depicted as the oscillogram of the signal in the drive circuit 900 in Fig. 9 A according to one embodiment of present invention, and Fig. 9 B describes in connection with Fig. 9 A.Fig. 9 B has described AC-input voltage V
aC, commutating voltage V
iN, rectified current I
iN, rectified current average current I
iN_AVG, electric current I
aC' with exchange input current I
aCwaveform.
For convenience of description, the embodiment of the present invention is with AC-input voltage V
aCbe specially sinusoidal waveform and carry out exemplary illustration, but the embodiment of the present invention is not limited in sinusoidal waveform.Rectifier 204 rectification AC-input voltage V
aC.In Fig. 9 B illustrated embodiment, commutating voltage V
iNthere is the sinusoidal waveform after rectification, that is, and AC-input voltage V
aCforward waveform retain, its negative sense waveform converts corresponding forward waveform to.
In one embodiment, the driving signal 962 that controller 910 produces is controlled rectified current I
iN.In one embodiment, rectified current I
iNsince a preset value (as 0 ampere), increase.As rectified current I
iNreach and commutating voltage V
iNafter a proportional value, rectified current I
iNdrop to preset value.As shown in Figure 9 B, rectified current I
iNaverage current I
iN_AVGwaveform and commutating voltage V
iNwaveform homophase substantially.
Rectified current I
iNfrom rectifier 204, flow out and flow into power converter 906.Rectified current I
iNit is the electric current I that flows into rectifier 204
aC' electric current after rectification.As shown in Figure 9 B, as AC-input voltage V
aCfor on the occasion of time, electric current I
aC' forward waveform and rectified current I
iNforward waveform similar; When exchanging input current voltage V
aCduring for negative value, electric current I
aC' negative sense waveform and rectified current I
iNwaveform corresponding.
In one embodiment, by employing, be coupled in the filter 920 between power supply 202 and rectifier 204, exchange input current I
aCwith electric current I
aC' mean value equate or proportional.Therefore, as shown in Figure 9 B, exchange input current I
aCwaveform and AC-input voltage V
aCwaveform homophase substantially.In theory, exchange input current I
aCwith AC-input voltage V
aChomophase.Yet, in actual applications, owing to having electric capacity in filter 920 and power converter 906, exchange input current I
aCwith AC-input voltage V
aCbetween may there is trickle differing.In addition, exchange input current I
aCwith AC-input voltage V
aCwaveform is also roughly similar.Therefore, the power factor of drive circuit 900 has obtained correction, thereby has improved the power supply quality of drive circuit 900.
Figure 10 shows that the circuit diagram of light source driving circuit 1000 according to still a further embodiment.In Figure 10, number identical parts with Fig. 2, Fig. 3 and Fig. 9 A and there is similar function.Figure 10 is described in connection with Fig. 4, Fig. 5 and Fig. 9 A.
In the example of Figure 10, drive circuit 1000 comprises: the filter 920, rectifier 204, power converter 906, load 208, sawtooth signal generator 902 and the controller 910 that are coupled in power supply 202.In one embodiment, load 208 comprises: LED source 208(is as light-emitting diode chain).It will be appreciated by persons skilled in the art that the load 208 in the embodiment of the present invention is not limited in this, load 208 can also comprise the light source of other types or the load of other types (as battery pack).Filter 920 can be the inductive-capacitive filter that (being not limited to) comprises a pair of inductance and a pair of electric capacity.In one embodiment, controller 910 comprises a plurality of ports, for example, and ZCD port, GND port, DRV port, vdd terminal mouth, FB port, COMP port and CS port.
In one embodiment, power converter 906 comprises: the input capacitance 1008 that is coupled in power line 912.Input capacitance 1008 can reduce the ripple of commutating voltage VIN, with the waveform of level and smooth commutating voltage VIN.In one embodiment, electric capacity 1008 has relatively little capacitance (for example, being less than 0.5 microfarad), to help to eliminate or reduce commutating voltage V
iNthe distortion of waveform.In addition, in one embodiment, because electric capacity 1008 is less, the electric current of the electric capacity 1008 of flowing through can be ignored.Therefore, when switch 316 is connected, the electric current I of the switch 316 of flowing through
214with the rectified current I flowing out from rectifier 204
iNabout equally.
△I
214=(V
IN-V
OUT)*T
ON/L
302, (1)
Wherein, T
oNthe time that represents switch 316 conductings, △ I
214represent electric current I
214variable quantity, L
302the inductance value that represents inductance 302.In one embodiment, controller 910 is controlled and is driven signal 962, makes T
oNremain a steady state value.So, if output voltage V
oUTsubstantially constant, at T
oNin the time interval, electric current I
214variable quantity △ I
214with commutating voltage V
iNproportional.In one embodiment, work as electric current I
214while being reduced to preset value (as 0 ampere), switch 316 closures.Accordingly, electric current I
214peak value and commutating voltage V
iNproportional.
When switch 316 disconnects, electric current I
214from ground, flow out, and flow through diode 314 and inductance 302, flow to LED source 208.Accordingly, electric current I
214according to formula (2), reduce:
△I
214=(-V
OUT)*T
OFF/L
302。(2)
Wherein, T
oFFthe turn-off time that represents switch 316.
In one embodiment, when switch 316 conducting, electric current I
iNwith electric current I
214substantially equate, when switching tube 316 disconnects, electric current I
iNequal 0 ampere.
The situation of inductance 304 inductive sensors 302, for example, whether the electric current of the inductance 302 of flowing through drops to predetermined current value, for example, zero ampere.In conjunction with embodiment illustrated in fig. 5, in one embodiment, when switch 316 is closed, monitor signal AUX is logic low, and when switch 316 disconnects, monitor signal AUX is logic high.Electric current I when the inductance 302 of flowing through
214be reduced to predetermined current value, the voltage of monitor signal AUX produces a trailing edge.The ZCD port of controller 910 is coupled in inductance 304, is used for receiving monitor signal AUX.
In one embodiment, power converter 906 comprises: output filter 1024.Output filter 1024 can be the electric capacity (for example, being greater than 400 microfarads) with relatively large capacitance.So, the electric current I of the LED source of flowing through 208
oUTrepresent electric current I
214mean value.
In one embodiment, controller 910 is integrated in an integrated circuit (IC) chip.The peripheral circuit assembly that resistance 1016 and resistance 1012, diode 1018 and electric capacity 1014 are this integrated circuit (IC) chip.Alternatively, sawtooth signal generator 902 and controller 910 also can be integrated in an integrated circuit (IC) chip, thereby can omit port CS, have reduced further size and the cost of drive circuit 1000.It will be appreciated by persons skilled in the art that power converter 906 can also have other structures, is not limited in the embodiment shown in Figure 10.
Figure 11 shows that the structural representation of Fig. 9 A middle controller 910 according to an embodiment of the invention.In Figure 11, number identical parts with Fig. 4 and Fig. 9 A and there is similar function.Figure 11 is described in connection with Fig. 4, Fig. 5, Fig. 9 A and Figure 10.
In one embodiment, controller 910 has similar structure to the controller 210 in embodiment illustrated in fig. 4, and difference is, port CS reception sawtooth signal 960 rather than first signal ISEN.Controller 910 produces and drives signal 962 according to sawtooth signal 960, secondary signal IAVG and monitor signal AUX.Controller 910 comprises: error amplifier 402, comparator 404 and pulse-width signal generator 408.Difference between the reference signal SET of 402 couples of secondary signal IAVG of error amplifier and expression target current value is amplified, and produces error signal VEA.Comparator 404 is sawtooth signal 960 and error signal VEA relatively, to produce comparison signal S.Pulse width modulating signal generator 408 produces driving signal 962 according to comparison signal S and monitor signal AUX.
In one embodiment, when monitor signal AUX represent the to flow through electric current I of inductance 302
214while dropping to preset value (as 0 ampere), drive signal 962 to switch to the first level (as logic high), with Closing Switch 316.When sawtooth signal 960 reaches error signal VEA, drive signal 962 to switch to second electrical level (as logic low), with cut-off switch 316.Advantageously, because port CS receives sawtooth signal 960 rather than first signal ISEN, the electric current I of the inductance 302 of flowing through
214peak value can not be limited to error signal VEA.Therefore, as described in formula (1), the electric current I of the inductance 302 of flowing through
214according to commutating voltage V
iNchange.For example, electric current I
214peak value be adjusted to and commutating voltage V
iNproportional rather than proportional with error signal VEA.
Figure 12 shows that the signal waveforms that light source driving circuit (as drive circuit 900 or 1000) generates or receives according to an embodiment of the invention.Figure 12 is described in connection with Fig. 4, Fig. 9 A, Fig. 9 B and Figure 10.Figure 12 has described commutating voltage V
iN, rectified current I
iN, rectified current I
iNaverage current I
iN_AVG, the LED source of flowing through 208 electric current I
oUT, the inductance 302 that represents to flow through electric current I
214first signal ISEN, error signal VEA, sawtooth signal 960 and drive signal 962.
As shown in figure 12, commutating voltage V
iNit is the sine wave signal after rectification.At t1 constantly, drive signal 962 to become logic high.Therefore, switch 316 closures, the electric current I of the inductance 302 that represents to flow through
214first signal ISEN increase.Meanwhile, sawtooth signal 960 is according to driving signal 962 to increase.
At t2 constantly, sawtooth signal 960 is increased to error signal VEA.Accordingly, controller 910 regulates and drives signal 962 is logic low, and sawtooth signal 960 drops to 0 volt.Drive signal 962 cut-off switch 316, therefore, first signal ISEN declines.In other words, sawtooth signal 960 and error signal VEA have determined to drive the time T of signal 962 logic highs
oN.
At t3 constantly, electric current I
214be reduced to predetermined current value (as 0 ampere), thus, controller 910 regulates and drives signal 962 is logic high, with Closing Switch 316.
In one embodiment, at commutating voltage V
iNone-period in, the electric current I of the LED source of flowing through 208
oUTwith electric current I
214mean value equate or proportional.In conjunction with the description of Figure 11, controller 910 regulates electric current I
oUTto the target current value being represented by reference signal SET.In addition, as shown in figure 12, represent electric current I
214first signal ISEN during t1 to t4 with during t5 to t6, there is identical waveform.So, electric current I
214mean value during t1 to t4 equates with the mean value during t5 to t6.Accordingly, electric current I
oUTremain on target current value.In one embodiment, T
oNby sawtooth signal 960 and error signal VEA, determined.In one embodiment, owing to driving in each cycle of signal 962, sawtooth signal 960 all equated from 0 volt of time that rises to error signal VEA, so T
oNconstant.According to formula (1), at T
oNin time, electric current I
214variable quantity △ I
214with commutating voltage V
iNproportional.So, as shown in figure 12, the peak value of first signal ISEN and input voltage V
iNproportional.
In one embodiment, when switch 316 is closed, electric current I
iNwaveform and electric current I
214waveform similarity, when switch 316 disconnects, electric current I
iNbe substantially equal to 0 ampere.At t1 to t6 in the time period, rectified current I
iNaverage current I
iN_AVGwith commutating voltage V
iNsubstantially homophase.Described in conjunction with Fig. 9 B, exchange input current I
aCwith AC-input voltage V
aCsubstantially homophase, thereby the power factor of having proofreaied and correct drive circuit 900, and then improved power supply quality.
Figure 13 shows that according to an embodiment of the invention for driving the method flow diagram 1300 of the drive circuit (for example,, for driving the drive circuit 900 or 1000 of LED source 208) of load.Figure 13 is described in connection with Fig. 9 A to Figure 12.The concrete steps that Figure 13 is contained are only as example.That is to say, the present invention is also applicable to carry out other rational steps or Figure 13 is carried out to improved step.
In step 1302, receive input voltage (for example, commutating voltage V
iN) and input current (for example, rectified current I
iN).
In step 1304, input voltage is converted into output voltage, for example, for load (, LED source) provides electric energy.
In step 1306, for example, for example, according to driving signal (, driving signal 962) to control the electric current of energy-storage units (, energy-storage units 214) of flowing through, to regulate the electric current of the load of flowing through.
In step 1308, first induced signal (for example, secondary signal IAVG) of the electric current of the load that receive to represent to flow through.In one embodiment, the first induced signal for example, is obtained by the second induced signal (, first signal ISEN) filtering of the energy-storage units electric current that represents to flow through.
In step 1310, according to driving signal to produce sawtooth signal.
In step 1312, by sawtooth signal and the first actuated signal control, drive signal, to regulate the electric current of the load of flowing through to target current value, and the average current by control inputs electric current and input voltage homophase substantially, to proofread and correct the power factor of drive circuit.In one embodiment, according to the difference of the first induced signal and reference signal, produce error signal, wherein, reference signal represent the to flow through target current value of LED source.Sawtooth signal and error signal are compared, and receive the monitor signal of indication energy-storage units situation.When the current reduction of energy-storage units is to preset value if monitor signal indication is flowed through, drive signal to be switched to the first state, according to the comparison value of sawtooth signal and error signal, drive signal to be switched to the second state.When driving signal in the first state, increase the electric current of the energy-storage units of flowing through, drive signal when the second state, the electric current of the energy-storage units that reduces to flow through.In one embodiment, if the electric current of the LED source of flowing through remains on target current value, the duration that sawtooth signal is increased to error signal from preset value is constant.
Figure 14 A is depicted as the block diagram of light source driving circuit 1400 in accordance with another embodiment of the present invention.In Figure 14 A, number identical parts with Fig. 2, Fig. 3 and Fig. 9 A and there is similar function.Figure 14 B is depicted as the signal waveforms that in Figure 14 A according to an embodiment of the invention, light source driving circuit 1400 generates or receives.Figure 14 A and Figure 14 B are described in connection with Fig. 9 A and Fig. 9 B.
In Figure 14 A illustrated embodiment, light source driving circuit 1400 comprises: with filter 920, rectifier 204, power converter 1406, light source 1408 and the controller 1410 of power supply 202 couplings.Power supply 202 produces AC-input voltage V
aC(for example, V
aCsine wave signal) with exchange input current I
aC.Exchange input current I
aCflow into filter 920.Electric current I
aC' from filter 920, flow out, and flow into rectifier 204.Rectifier 204 receives AC-input voltage V by filter 920
aC, and commutating voltage V is provided on power line 912
iN(that is, flow into the input voltage V of power converter 1406
iN) and rectified current I
iN(that is, flow into the input current I of power converter 1406
iN).Power line 912 is coupled between rectifier 204 and power converter 1406.
In one embodiment, power converter 1406 comprises: voltage filter 1420, transformer 1422 and switch 1424.Voltage filter 1420 receives input voltage V
iN, and filter input voltage V
iNto produce burning voltage V
rEG.For example, voltage filter 1420 has filtered input voltage V
iNhigh-frequency harmonic component.Therefore, as shown in Figure 14B, burning voltage V
rEGwaveform than input voltage V
iNwaveform more stable.Transformer 1422 is by burning voltage V
rEGbe converted to output voltage V
oUT, think that light source 1408 provides electric energy.Therefore, output voltage V
oUTwaveform can not be subject to input voltage V
iNthe impact that (for example sinusoidal wave) changes.Accordingly, owing to having reduced or eliminated the electric current I of the light source 1408 of flowing through
oUTripple, thereby reduced the luminous line frequency of light source 1408, disturb.
In one embodiment, when switch 1424 works in the first state, input current I
iNincrease; When switch 1424 works in the second state, input current I
iNreduce.Controller 1410 is controlled the duration of the second state, so that input current I
iNbe reduced to preset value (for example, earth potential).Controller 1410 is also controlled the duration of the first state, so that input current I
iNfrom preset value, increase to and input voltage V
iNproportional peak value.Accordingly, input current I
iNaverage current I
iN_AVGwith input voltage V
iNsubstantially homophase.Be similar to Fig. 9 B illustrated embodiment, exchange input current I
aCwith AC-input voltage V
aCsubstantially homophase.Ideally, AC-input voltage V
aCwith exchange input current I
aCit is homophase.Yet, in actual applications, due to the existence of electric capacity in filter 920 and power converter 1406, exchange input current I
aCwith AC-input voltage V
aCbetween may there is trickle differing.In addition, exchange input current I
aCwaveform and AC-input voltage V
aCwaveform also roughly similar.Therefore, proofreaied and correct the power factor of light source driving circuit 1400.
Advantageously, by switch 1424 is switched between the first state and the second state, proofreaied and correct the power factor of light source driving circuit 1400, and by output current I
oUTbe adjusted to target current value.Therefore, the power supply quality of light source driving circuit 1400 and the precision of Current Control are all improved.Owing to only having adopted single switch 1424, reduced size and the cost of light source driving circuit 1400.
Figure 15 shows that the circuit diagram of light source driving circuit 1500 in Figure 14 A according to an embodiment of the invention.In Figure 15, number identical parts with Fig. 2, Fig. 3, Fig. 9 A and Figure 14 A and there is similar function.Figure 15 is described in connection with Figure 14 A and Figure 14 B.In one embodiment, controller 1410 comprises a plurality of ports, for example: port VIN, port COMP, port GND, port DRV, port ZCD and port FB.
In one embodiment, voltage filter 1420 comprises: inductance 1512, diode D15(diode D15 can be considered as the second diode in the embodiment of the present invention), diode D16(diode D16 can be considered as the first diode in the embodiment of the present invention) and capacitor C 15.Transformer 1422 can be inverse-excitation type (flyback) converter, comprising: armature winding 1504, secondary winding 1506, auxiliary winding 1508 and magnetic core 1502.With switch 1424 alternations of diode D16 and armature winding 1504 couplings for example, for example, in the first state (, conducting state) and the second state (, off state), to control the input current I of the inductance 1512 of flowing through
iNoutput current I with the LED source 1408 of flowing through
oUT.
In one embodiment, controller 1410 produces and for example drives signal 1462(, pulse width modulating signal), with control switch 1424.More specifically, in one embodiment, for example, when driving signal 1462 to there is logic high (, during conducting state), switch 1424 conductings, diode D15 reverse bias, diode D16 forward bias.Burning voltage V
rEGgive transformer 1422 power supplies.Electric current I
pRIflow through armature winding 1504, switch 1424 and ground.Electric current I
pRIincrease with by electrical power storage in magnetic core 1502.In addition input current I,
iNinductance 1512, diode D16 and switch 1424 and input current I flow through
iNthereby increasing is inductance 1512 chargings, input current I
iNcan be drawn by formula (3):
△I
IN=V
IN*T
CH/L
1512, (3)
Wherein, T
cHthe charging interval that represents inductance 1512, △ I
iNrepresent input current I
iNvariable quantity, L
1512the inductance value that represents inductance 1512.In one embodiment, the charging interval T of inductance 1512
cHequal the ON time T of switch 1424
oN.
For example, when driving signal 1462 to have logic low (, during off state), switch 1424 disconnects, diode D15 forward bias, diode D16 reverse bias.Transformer 1422 electric discharge provides electric energy for Light-Emitting Diode light source 208.Therefore, the flow through electric current I of secondary winding 1506
sEreduce.In addition input current I,
iNinductance 1512, diode D15 and capacitor C 15 and input current I flow through
iNreduce, make inductance 1512 electric discharges, as the formula (4):
△I
IN=(V
IN-V
REG)*T
DISCH/L
1512. (4)
Wherein, T
dISCHthe discharge time that represents inductance 1512.Owing to working as input current I
iNbe reduced to zero ampere-hour, inductance 1512 stops electric discharge, therefore, and T discharge time of inductance 1512
dISCHcan with the turn-off time T of switch 1424
oFFdifferent.
In one embodiment, inductance 1512 and capacitor C 15 form inductive-capacitive filter.Inductive-capacitive filter filters input voltage V
iNhigh-frequency harmonic component.Therefore, reduced voltage V
rEGin waveform due to input voltage V
iNthe ripple that causes of variation.Transformer 1422 is by burning voltage V
rEGbe converted to output voltage V
oUT, therefore, output voltage V
oUTbe not subject to input voltage V yet
iNthe impact changing.
In one embodiment, auxiliary winding 1508 is by port ZCD and controller 1410 couplings.Auxiliary winding 1508 provides current monitoring signal 1466, current monitoring signal 1466 indicator current I
sEwhether drop to preset value (for example, zero ampere).The port FB of controller 1410 receives induced signal 1464, and induced signal 1464 is indicated the output current I of the LED source 208 of flowing through
oUT.In one embodiment, a plurality of signal controlling of controller 1410 based on comprising current monitoring signal 1466 and induced signal 1464 drive the duty ratio of signal 1462, with regulation output electric current I
oUTto target current value.The operation of controller 1410 will further describe in Figure 16.
In one embodiment, controller 1410 is also by driving signal 1462 to control ON time T
oNwith turn-off time T
oFF, with the power factor of calibration light source drive circuit 1500.More specifically, in one embodiment, controller 1410 is by time T
oFFbe set to and be greater than time threshold T
tH.According to formula (4), can be drawn by formula (5) discharge time of inductance 1512:
T
DISCH=△I
IN*L
1512/(V
IN-V
REG). (5)
As shown in Figure 14B, △ I
iNdriving signal 1462, in the different time cycles, can be different.In one embodiment, time threshold T
tHvalue can be set to be equal to or greater than maximum discharge time of the T of inductance 1512
dISCH_MAX.Therefore, the turn-off time T of switch 1424
oFFbe enough to allow input current I
iNbe decreased to zero ampere.In addition, controller 1410 is by ON time T
oNbe stabilized in a constant value.So, according to formula (3), input current I
iNfor example, from preset value (, zero ampere), increase to and input voltage V
iNproportional peak value.Therefore, as Figure 14 A and Figure 14 B described, the power factor of having proofreaied and correct light source driving circuit 1500, has improved the power supply quality of light source driving circuit 1500.
Figure 16 shows that the structural representation of Figure 14 A middle controller 1410 according to an embodiment of the invention.In Figure 16, number identical parts with Fig. 4 and Fig. 9 A and there is similar function.Figure 16 is described in connection with Fig. 4, Fig. 5, Figure 10 and Figure 11.
In one embodiment, controller 1410 except comprising sawtooth signal generator 1602, have with Figure 11 in the similar structure of controller 910.Sawtooth signal generator 1602 produces sawtooth signal 1660.In one embodiment, the operation of sawtooth signal generator 1602 and the sawtooth signal generator 902 shown in Figure 10 are similar.When driving signal 1462 actuating switch 1424, sawtooth signal 1660 rises, and when driving signal 1462 stopcock 1424, sawtooth signal 1660 drops to zero ampere.
In one embodiment, when current monitoring signal 1466, indicate the electric current I of the secondary winding 1506 of flowing through
sEdrop to preset value (for example, zero ampere), driven signal 1462 to there is high level with actuating switch 1424.When sawtooth signal 1660 reaches error signal VEA, drive signal 1462 to there is low level with stopcock 1424.
Figure 17 shows that in accordance with another embodiment of the present invention the method flow diagram 1700 for driving light source 1408.Figure 17 is described in connection with Figure 14 A to Figure 16.The concrete steps that Figure 17 is contained are only as example.That is to say, the present invention is also applicable to carry out other rational steps or Figure 17 is carried out to improved step.
In step 1702, receive input current (for example, input current I
iN) and input voltage (for example, input voltage V
iN).
In step 1704, for example filter input voltage, so that burning voltage (, burning voltage V to be provided
rEG).
In step 1706, burning voltage is converted to output voltage (for example, output voltage V
oUT), think LED source power supply.
In step 1708, produce to drive signal (for example, driving signal 1462) so that switch (for example, switch 1424) alternation for example, for example, in the first state (, conducting state) and the second state (, off state).In the first state, input current increases; In the second state, input current reduces.
In step 1710, control the duration of the first state, make input current from preset value, increase to peak value proportional to input voltage in the first state, control the duration of the second state, make input current in the second state, be reduced to preset value (for example, zero ampere).
In step 1712, control the ratio between the duration of the first state and the duration of the second state, with what regulate the LED source of flowing through, output current to target current value.
Embodiments of the invention provide the drive circuit of driving load (for example, LED source).This drive circuit comprises voltage filter, transformer and controller.Voltage filter receives and filters input voltage, so that burning voltage to be provided.Transformer is converted to output voltage by burning voltage, is LED source power supply.Controller produce to drive signal so that switch alternation in the first state and the second state.Controller is controlled the duration of the first state, makes input current from preset value, increase to peak value proportional to input voltage in the first state, controls the duration of the second state, makes input current be decreased to preset value in the second state.Controller is controlled the ratio between the duration of the first state and the duration of the second state, with what regulate the LED source of flowing through, outputs current to target current value.Advantageously, owing to having reduced or eliminated the ripple of the output current of the LED source of flowing through producing because of the variation of input voltage, thereby the line frequency that has further reduced light source luminescent disturbs.In addition, proofreaied and correct the power factor of drive circuit to improve the power supply quality of drive circuit, and improved the Current Control precision of drive circuit.
Above embodiment and accompanying drawing are only conventional embodiment of the present invention.Obviously, under the prerequisite that does not depart from the present invention's spirit that claims define and invention scope, can have and variously augment, revise and replace.It should be appreciated by those skilled in the art that the present invention can change to some extent in form, structure, layout, ratio, material, element, assembly and other side according to concrete environment and job requirement in actual applications under the prerequisite that does not deviate from invention criterion.Therefore, embodiment disclosed here is only illustrative rather than definitive thereof, and scope of the present invention is defined by claims and legal equivalents thereof, and is not limited to description before this.
Claims (20)
1. for a drive circuit for LED source power supply, it is characterized in that, described drive circuit comprises:
Voltage filter, for receiving input voltage and filtering described input voltage, so that burning voltage to be provided;
Be coupled in the transformer of described voltage filter, for described burning voltage is converted to output voltage, think described LED source power supply; And
Be coupled in the switch of described voltage filter and described transformer;
Be coupled in the controller of described switch, for generation of driving signal so that described switch alternation in the first state and the second state, when described switch is during in described the first state, the input current of described voltage filter of flowing through increases, when described switch is during in described the second state, described input current reduces
Wherein, described controller is controlled the duration of described the first state, so that described input current increases to and the proportional peak value of described input voltage from preset value in described the first state, control the duration of described the second state, so that described input current is decreased to described preset value in described the second state
Described controller is also controlled the ratio between the duration of described the first state and the duration of described the second state, with what regulate the described LED source of flowing through, outputs current to target current value.
2. drive circuit according to claim 1, is characterized in that, described voltage filter comprises:
Inductance, described inductance is coupled by the first diode and described switch, by the second diode and capacitive coupling,
Wherein, when described switch is during in described the first state, described input current flow through described inductance, described the first diode and described switch; When described switch is during in described the second state, described input current flow through described inductance, described the second diode and described electric capacity.
3. drive circuit according to claim 2, is characterized in that, described inductance and described electric capacity form inductive-capacitive filter, for filtering a plurality of harmonic components of described input voltage, to produce described burning voltage.
4. drive circuit according to claim 1, is characterized in that, described transformer comprises:
Armature winding, for receiving described burning voltage; And
Secondary winding, for providing described output voltage to described LED source,
Wherein, when described switch is during in described the first state, the electric current of flow through described armature winding and described switch increases; When described switch is during in described the second state, the electric current of the described secondary winding of flowing through reduces.
5. drive circuit according to claim 1, is characterized in that, the duration of described the first state is enough to make described input current to increase to described peak value proportional to described input voltage from described preset value.
6. drive circuit according to claim 1, is characterized in that, the duration of described the second state is enough to make described input current to be reduced to described preset value.
7. drive circuit according to claim 1, is characterized in that, described controller comprises:
Sawtooth signal generator, for producing sawtooth signal according to described driving signal;
Error amplifier, for producing error signal according to induced signal and reference signal, described induced signal is indicated the described output current of the described LED source of flowing through, and described reference signal is indicated the described target current value of described output current; And
Be coupled in the comparator of described error amplifier, for described sawtooth signal and described error signal are compared, to control described driving signal.
8. drive circuit according to claim 7, is characterized in that, when described switch is during in described the first state, described sawtooth signal increases; When described sawtooth signal increases to described error signal, described switching over is to described the second state.
9. drive circuit according to claim 8, is characterized in that, if the described output current of the described LED source of flowing through remains on described target current value, the time that described sawtooth signal increases to described error signal from preset value is constant.
10. drive circuit according to claim 1, is characterized in that, described drive circuit also comprises:
Rectifier, exchanges input current and AC-input voltage for receiving, and described input current is provided,
Wherein, described controller is proofreaied and correct the power factor of described drive circuit, makes described interchange input current and described AC-input voltage homophase substantially.
11. 1 kinds of power converters for LED source power supply, described power converter comprises:
Switch, for according to pulse signal alternation at the first state and the second state;
Voltage filter with described switch coupling, described voltage filter comprises: inductance and electric capacity, described voltage filter filters input voltage so that burning voltage to be provided, wherein, when described switch is during in described the first state, input current flow through described inductance and described switch, described input current increases to and the proportional peak value of described input voltage from preset value; When described switch is during in described the second state, described input current flow through described inductance and described electric capacity, described input current is reduced to described preset value; And
Transformer, described transformer comprises: the armature winding and the secondary winding that are coupled in described switch, described transformer is converted to output voltage by described burning voltage, think described LED source power supply, wherein, when described switch is during in described the first state, described transformer is powered by described burning voltage, and the electric current of flow through described armature winding and described switch increases; When described switch is during in described the second state, thereby be described LED source, the electric discharge of described transformer powers, the electric current of the described secondary winding of flowing through reduces,
Wherein, by controlling the duty ratio of described pulse signal, with what regulate the described LED source of flowing through, output current to target current value.
12. power converters according to claim 11, is characterized in that, described transformer also comprises:
Auxiliary winding, for generation of current monitoring signal, whether the flow through described electric current of described secondary winding of described current monitoring signal designation is reduced to preset value,
Wherein, described switch is switched to described the first state according to described current monitoring signal from described the second state.
13. power converters according to claim 11, is characterized in that, the duration of described the second state is greater than the time of described input current from described peak reduction to described preset value.
14. power converters according to claim 11, is characterized in that, the duration of described the first state is stabilized in steady state value.
15. 1 kinds for LED source provides the method for electric energy, it is characterized in that, described method comprises:
Receive input voltage and input current;
Filter described input voltage, so that burning voltage to be provided;
Described burning voltage is converted to output voltage, thinks described LED source power supply;
Produce to drive signal, so that switch alternation is in the first state and the second state, wherein, in described the first state, described input current increases, and in described the second state, described input current reduces;
Control the duration of described the first state, described input current is increased to and the proportional peak value of described input voltage from preset value in described the first state; Control the duration of described the second state, make described input current be reduced to described preset value in described the second state; And
Control the ratio between the duration of described the first state and the duration of described the second state, with what regulate the described LED source of flowing through, output current to target current value.
16. methods according to claim 15, is characterized in that, the described step that described burning voltage is converted to described output voltage also comprises:
The armature winding of transformer receives described burning voltage;
The secondary winding of described transformer provides described output voltage for described LED source;
In described the first state, the electric current of flow through described armature winding and described switch increases; And
In described the second state, the electric current of the described secondary winding of flowing through reduces.
17. methods according to claim 15, is characterized in that, the duration of described the first state is enough to make described input current to increase to described peak value proportional to described input voltage from described preset value.
18. methods according to claim 15, is characterized in that, the duration of described the second state is enough to make described input current to be reduced to described preset value.
19. methods according to claim 15, is characterized in that, described generation drives the step of signal also to comprise:
According to described driving signal, produce sawtooth signal;
Based on induced signal and reference signal, produce error signal, described induced signal is indicated the described output current of the described LED source of flowing through, and described reference signal is indicated the described target current value of described output current;
More described sawtooth signal and described error signal, to control described driving signal; And
When described sawtooth signal increases to described error signal, described switch is switched to described the second state from described the first state.
20. methods according to claim 19, is characterized in that, if the described output current of the described LED source of flowing through remains on described target current value, the time that described sawtooth signal increases to described error signal from preset value is constant.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US13/530,935 US20120262079A1 (en) | 2010-03-04 | 2012-06-22 | Circuits and methods for driving light sources |
| US13/530,935 | 2012-06-22 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103517506A true CN103517506A (en) | 2014-01-15 |
| CN103517506B CN103517506B (en) | 2016-05-04 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210361522.5A Expired - Fee Related CN103517506B (en) | 2012-06-22 | 2012-09-25 | For the drive circuit of LED source power supply and method, power converter |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP2014007143A (en) |
| CN (1) | CN103517506B (en) |
| GB (1) | GB2503316B (en) |
| TW (1) | TWI505746B (en) |
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| CN105430795A (en) * | 2015-12-11 | 2016-03-23 | 成都翰道科技有限公司 | Energy saving control system of intelligent LED lamp based on compound double-order filter circuit |
| CN107301835A (en) * | 2016-04-13 | 2017-10-27 | 群创光电股份有限公司 | Light emitting diode display |
| CN116981123A (en) * | 2023-08-09 | 2023-10-31 | 桂林市啄木鸟医疗器械有限公司 | A device and method for emitting light |
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| JP6256171B2 (en) * | 2014-04-18 | 2018-01-10 | 三菱電機株式会社 | Lighting device and lighting apparatus |
| GB2544820B (en) * | 2015-11-30 | 2021-03-03 | Tridonic Gmbh & Co Kg | A low voltage power supply using an earth connection on a terminal block |
| KR101923158B1 (en) * | 2017-12-29 | 2019-02-27 | 주식회사 디에스이 | multiple stages dimming device of LED light using the wall-switch |
| JP7016018B2 (en) * | 2018-05-31 | 2022-02-04 | パナソニックＩｐマネジメント株式会社 | Lighting device and lighting equipment |
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Also Published As
| Publication number | Publication date |
|---|---|
| JP2014007143A (en) | 2014-01-16 |
| GB2503316A (en) | 2013-12-25 |
| GB2503316B (en) | 2015-10-14 |
| CN103517506B (en) | 2016-05-04 |
| TW201401922A (en) | 2014-01-01 |
| GB201306005D0 (en) | 2013-05-15 |
| TWI505746B (en) | 2015-10-21 |
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