CN100574550C - Multi-lamp drive system - Google Patents

Abstract

A multi-lamp driving system is used to drive a lamp module including multiple lamps. The multi-lamp driving system includes a converter for converting the input voltage into a DC voltage, a driving circuit for converting the DC voltage into an AC voltage, a pulse width modulation controller electrically connected between the lamp module and the converter, It is used to control the output voltage of the converter according to the signal fed back from the lamp module; a bus controller electrically connected between the lamp module and the drive circuit is used to adjust the operating frequency according to the signal fed back from the lamp module, and to control the voltage of the drive circuit. voltage output. The multi-lamp driving system provided by the present invention only uses one pulse width modulation controller, the system structure is simple, and the cost is effectively reduced.

Description

Multi-lamp drive system

【Technical field】

The invention relates to a multi-load driving system, in particular to a multi-lamp driving system applied to a liquid crystal display (liquid crystal display, LCD) backlight module.

【Background technique】

Discharge lamps are commonly used in the backlight of LCD panels, and have terminal voltage characteristics that vary according to the current state and the frequency of the AC signal applied to the lamp. The discharge lamp has a negative impedance characteristic, and its equivalent impedance will decrease as the input power increases. The circuit that supplies power/power to the lamp must have a controllable AC supply source, and a feedback circuit that can accurately detect the current in the lamp in order to maintain the stability of the circuit and have the function of load regulation.

A system for driving multiple discharge lamps in the prior art usually uses two pulse width modulation controllers, one for regulating the magnitude of the current flowing through the discharge lamps, and one for stabilizing the DC voltage input to the driving circuit.

Please refer to FIG. 1 , which is a lamp driving system adopted in the prior art. The lamp driving system includes a converter 1 , a bridge driving circuit 2 , a lamp module 3 , a pulse width modulation controller 4 and a bridge controller 5 . Wherein, the pulse width modulation controller 4 is used to control the converter through pulse width modulation according to the voltage converted by the converter, so as to stabilize the output DC voltage. The bridge controller 5 is also a pulse width modulation controller, which is used to adjust the strength of the current flowing through the lamp module according to the current flowing through the lamp module. This lamp drive system uses two pulse modulation controllers, one to stabilize the DC voltage converted by the converter and the other to regulate the current flowing through the individual lamps in the lamp module. However, the cost of the pulse modulation controller is relatively high, especially when driving multiple sets of lamp tubes, the structure of the driving system is complicated, and the use of multiple pulse modulation controllers leads to high cost of the entire lamp tube driving system.

Therefore, there is a need for a driving system for multiple lamps applied to a backlight module of a liquid crystal display (LCD), which has a simple structure and is cheap.

【Content of invention】

The technical problem to be solved by the present invention is to provide a multi-lamp driving system, which only uses one pulse width modulation controller.

In order to solve the above technical problems, the present invention provides a multi-lamp driving system, which is used to drive a lamp group module including a plurality of lamps. The multi-lamp driving system includes a converter for converting the input voltage into a DC voltage, a driving circuit for converting the DC voltage into an AC voltage, a pulse width modulation controller electrically connected between the lamp module and the converter, It is used to control the output voltage of the converter according to the signal fed back from the lamp module; a bus controller electrically connected between the lamp module and the drive circuit is used to adjust the working frequency and control the drive circuit according to the signal fed back from the lamp module.

Since the system of the present invention only uses one pulse width modulation controller, especially in the case of driving multiple groups of lamp tubes, the utilization rate of the pulse width modulation controller is minimized, so the system structure is simple and the cost is effectively reduced.

【Description of drawings】

FIG. 1 is a structure diagram of a conventional multi-lamp driving system.

Fig. 2 is a structure diagram of the first embodiment of the multi-lamp driving system of the present invention.

Fig. 3 is a structure diagram of the second embodiment of the multi-lamp driving system of the present invention.

Fig. 4 is a structure diagram of the third embodiment of the multi-lamp driving system of the present invention.

FIG. 5 is a structure diagram of a fourth embodiment of the multi-lamp driving system of the present invention.

【Detailed ways】

Referring to FIG. 2 , it is a structure diagram of the first embodiment of the multi-lamp driving system of the present invention.

In the present invention, the multi-lamp driving system includes an AC/DC converter 11, a driving circuit 12, a lamp module 13, a pulse width modulation controller 14, and a bus controller (BUS Inverter Controller) 15. Wherein, the light tube module 13 includes a plurality of light tubes.

The AC/DC converter 11 is used to receive AC voltage and convert it to DC voltage.

The drive circuit 12 is electrically connected to the AC/DC converter 11 for converting the received DC voltage into an AC voltage. The drive circuit 12 converts the received DC voltage into an AC voltage by utilizing the principle that a switch passes voltage when it is turned on, but does not pass the voltage when it is turned off. When the switch is turned on, the switch receives a DC voltage and outputs a high-potential signal, and when the switch is closed, the DC voltage cannot pass through the switch and outputs a low-potential signal. Therefore, the DC voltage is passed through a cycle A switch with a characteristic of turning on and off generates periodic pulses, and this periodic pulse is the AC voltage output by the driving circuit 12 .

In the embodiment of the present invention, the driving circuit 12 is a half-bridge driving circuit, and in other embodiments of the present invention, the driving circuit 12 can also be a full-bridge driving circuit, or a push-pull driving circuit.

The lamp module 13 is electrically connected to the driving circuit 12, and is used for receiving the AC voltage output by the driving circuit 12 to light each lamp.

The pulse width modulation controller 14 is connected to the lamp module 13 and the AC/DC converter 11 , and is used to output a control signal to the AC/DC converter 11 according to the current feedback signal flowing through each lamp in the lamp module 13 . The AC/DC converter 11 changes the strength of its output DC voltage according to the control signal. The strength of the DC voltage output by the AC/DC converter 11 affects the brightness of each lamp in the lamp module 13 via the drive circuit 12 . Therefore, when the brightness of each lamp in the lamp module 13 needs to be corrected or changed, that is, when the current flowing through each lamp needs to be adjusted, the AC/DC converter 11, the driving circuit 12, the lamp module 13 and the pulse width The modulation controller 14 will form a loop to change the DC voltage output by the AC/DC converter 11 through the loop feedback current of each lamp in the lamp module 13 , thereby controlling the brightness of each lamp in the lamp module 13 .

The bus controller 15 is electrically connected to the lamp module 13 and the driving circuit 12 , and is used to adjust the operating frequency of the bus controller 15 according to the current flowing through each lamp of the lamp module 13 and increase the AC output voltage of the driving circuit 12 . When each lamp in the lamp module 13 has not been lit, the lamp module 13 forms a loop with the bus controller 15 and the drive circuit 12, and the loop senses that each lamp in the lamp module 13 has no current, and the bus controller 15 adjust the working frequency, control the driving circuit 12 to increase the output AC voltage, and light up each lamp in the lamp module 13 .

Referring to FIG. 3 , it is a structure diagram of the second embodiment of the multi-lamp driving system of the present invention. The difference between the multi-lamp driving system and the first embodiment of the present invention is only that the AC/DC converter 11 is used in the first embodiment, that is, the multi-lamp driving system uses AC voltage input to drive multiple lamps, while in the first embodiment In the second embodiment, a DC/DC converter 11' is used, that is, the multi-lamp driving system uses a DC voltage input to drive multiple lamps.

When the number of lamps to be driven is too large and the driving circuit 12 cannot bear the power required by many lamps, the present invention provides another preferred embodiment of driving multiple lamp modules.

Please refer to FIG. 4 , which is a structure diagram of driving multiple lamp modules in the present invention. The circuit includes a plurality of AC/DC converters 11, 21, ..., N1, a plurality of drive circuits 12, 22, ..., N2, a plurality of lamp modules 13, 23, ..., N3, a Multi-phase pulse width modulation controller 14', a bus controller 15.

Connection relation of AC/DC converter N1 (N=2, 3,...), drive circuit N2 (N=2, 3,...) and lamp module N3 (N=2, 3,...) The connection relationship between the AC/DC converter 11 , the driving circuit 12 and the lamp module 13 in FIG. 1 is consistent.

The multi-phase PWM controller 14' is electrically connected to the AC/DC converter N1 (N=1, 2, ...) and the lamp module N3 (N = 1, 2, ...). The bus controller 15 is electrically connected to the drive circuit N2 (N=1, 2, . . . ) and the lamp module N3 (N=1, 2, . . . ).

The multi-phase pulse width modulation controller 14' outputs control signals to the corresponding AC/DC converters N1 (N=1, 2, ...) at different times according to the preset timing, to control the AC/DC converters N1 (N=1, 2, . . . ) receives AC voltage input at different times.

First, the multi-phase PWM controller 14' controls the AC/DC converter 11 to receive the AC voltage, and the AC/DC converter 11 converts the AC voltage into a DC voltage. The driving circuit 12 converts the DC voltage into an AC voltage for driving each lamp of the lamp module 13 . The bus controller 15 senses the current of the lamp module 13 , if there is no current in the lamp module 13 , it adjusts its operating frequency to increase the AC voltage output by the drive circuit 12 , so as to light each lamp in the lamp module 13 .

If setting and lighting each lamp in the lamp module 13 is completed within the first time sequence of the multiphase pulse width modulation controller 14', then in the Nth (Nth) sequence of the multiphase pulse width modulation controller 14' =2, 3, . . . ), the multi-phase pulse width modulation controller 14' controls the AC/DC converter N1 (N=2, 3, . . . ) to receive the AC voltage, and the AC/DC converter N1 ( N=2, 3, . . . ) convert the AC voltage into a DC voltage. The driving circuit N2 converts the DC voltage into an AC voltage for driving each lamp of the lamp module N3 (N=2, 3, . . . ). If the bus controller 15 senses that there is no current flowing through the lamp module 23, it adjusts the operating frequency and increases the AC voltage output by the driving circuit N2 (N=2, 3, . . . ), thereby lighting the lamp module N3 ( Each lamp tube in N=2,3,...).

When the brightness of each lamp in the lamp module N3 needs to be corrected or changed, the multi-phase pulse width modulation controller 14' sequentially controls the DC voltage output by the AC/DC converter N1 according to the sequence, thereby adjusting the brightness of each lamp in the lamp module N3 tube brightness.

Assuming that adjusting the brightness of the lamp module 13 is completed within the first time sequence of the multi-phase pulse width modulation controller 14', then in the Nth (N=1, 2, .. .) Within a period of time, the AC/DC converter N1 (N=1, 2, ...), the drive circuit N2 (N = 1, 2, ...), the lamp module N3 (N = 1, 2, . . . ) and the multi-phase pulse width modulation controller 14' will form a loop to control the AC/ The DC voltage output by the DC converter N1 (N=1, 2, . . . ) achieves the purpose of controlling the brightness of each lamp in the lamp module N3 (N=1, 2, . . . ).

Referring to FIG. 5 , it is a structure diagram of a fourth embodiment of the multi-lamp driving system of the present invention. The circuit architecture of the multi-lamp drive system is basically the same as that of the third embodiment of the present invention, the difference is only that the third embodiment uses an AC/DC converter N1' (N=1, 2, ...), that is, the multi-lamp The lamp driving system can use AC voltage input to drive multiple lamps, and in the second embodiment, a DC/DC converter N1' (N=1, 2, . . . ) is used, that is, the multi-lamp driving system also Multiple lamps can be driven by DC voltage input.

Claims (12)

1. multi-lamp-tube driving system, be used to drive a fluorescent tube module that comprises a plurality of fluorescent tubes, this multi-lamp-tube driving system comprises that one is converted to the transducer of direct voltage with input voltage, and one is converted to the drive circuit of alternating voltage with direct voltage, it is characterized in that this system also comprises:

One is electrically connected on the Pwm controller between fluorescent tube module and the transducer, is used for the output voltage according to the signal controlling transducer of fluorescent tube module feedback;

One is electrically connected on the bus control unit between fluorescent tube module and the drive circuit, is used for adjusting operating frequency, control Driver Circuit according to the signal of fluorescent tube module feedback.

2. multi-lamp-tube driving system as claimed in claim 1 is characterized in that transducer is an AC/DC converter, and the alternating voltage that is used for receiving is converted to direct voltage.

3. multi-lamp-tube driving system as claimed in claim 1 is characterized in that transducer is a DC-DC converter, and the direct voltage that is used for receiving is converted to direct voltage.

4. multi-lamp-tube driving system as claimed in claim 1 is characterized in that if the signal of fluorescent tube module feedback is not have electric current flowing through lamps tube module, then bus control unit control Driver Circuit output AC voltage.

5. multi-lamp-tube driving system as claimed in claim 1 is characterized in that drive circuit is semibridge system, full-bridge type or push-pull type.

6. multi-lamp-tube driving system, be used to drive a plurality of fluorescent tube modules that comprise a plurality of fluorescent tubes, this multi-lamp-tube driving system comprises and a plurality of input voltage is converted to the transducer of direct voltage, a plurality of direct voltage is converted to the alternating voltage drive circuit, it is characterized in that this system also comprises:

One is electrically connected on the leggy Pwm controller between a plurality of fluorescent tube modules and a plurality of transducer, according to the output voltage of the signal controlling transducer of a plurality of fluorescent tube modules feedback;

One is electrically connected on the bus control unit between a plurality of fluorescent tube modules and a plurality of drive circuit, is used for adjusting operating frequency, control Driver Circuit according to the signal of fluorescent tube module feedback.

7. multi-lamp-tube driving system as claimed in claim 6 is characterized in that transducer is an AC/DC converter, and the alternating voltage that is used for receiving is converted to direct voltage.

8. multi-lamp-tube driving system as claimed in claim 6 is characterized in that transducer is a DC-DC converter, and the direct voltage that is used for receiving is converted to direct voltage.

9. multi-lamp-tube driving system as claimed in claim 6, it is characterized in that the leggy Pwm controller outputs control signals to corresponding converter according to its sequential in the different time, control different transducers and receive the alternating voltage input in the different time.

10. multi-lamp-tube driving system as claimed in claim 6 is characterized in that the leggy Pwm controller controls the direct voltage of different switching device output successively according to its sequential, thereby regulates the brightness of each corresponding fluorescent tube in the fluorescent tube module.

11. multi-lamp-tube driving system as claimed in claim 6 is characterized in that then bus control unit is by adjusting the output AC voltage that operating frequency improves drive circuit if the signal of fluorescent tube module feedback is not have electric current flowing through lamps tube module.

12. multi-lamp-tube driving system as claimed in claim 6 is characterized in that drive circuit is semibridge system, full-bridge type or push-pull type.

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