CN104936329A - Devices for driving light-emitting diodes using high voltage - Google Patents

Abstract

An apparatus for driving a plurality of light emitting diodes to which a high voltage is applied includes a plurality of light emitting diodes divided into a plurality of light emitting diode segments connected in series, and a switching voltage detector and a current limiter connected in series thereto. Each LED segment is connected in parallel with a switch, and a high input voltage supplies power to the entire LED device. The switching voltage detector generates a first mode change signal when the input voltage rises, and generates a second mode change signal when the input voltage falls. A controller receives the two mode change signals and generates a plurality of control signals to respectively control each switch so as to change the operation mode of the LED device.

Description

Devices for driving light-emitting diodes using high voltage

technical field

The present invention relates to light emitting diode (LED) based lighting devices, in particular a driving device for a LED based lighting device using high voltage.

Background technique

Light-emitting diode (LED) is a semiconductor-based light source, which was often used in low-power consumption meters and indicators of home appliances in the past. Due to the advancement of technology to improve brightness, the application of light-emitting diodes in various lighting devices has become more and more common. . For example, high-brightness light-emitting diodes have been widely used in traffic lights, vehicle lights, and brake lights. In recent years, lighting fixtures using strings of high-voltage LEDs have also been developed to replace traditional incandescent and fluorescent bulbs.

The current-to-voltage (IV) characteristic curve of a light-emitting diode is similar to a general ordinary diode. When the voltage applied to the light-emitting diode is less than the forward voltage of the diode, only a very small current flows through the light-emitting diode. When the voltage exceeds the forward voltage, the current through the LED increases significantly. In general, the luminous intensity of an LED-based lighting device is proportional to the current passing through most of the operating range, but not when operating at high currents. Generally, the driving device designed for LED-based lighting devices is mainly to provide a constant current so as to emit stable light and prolong the life of the LED.

In order to improve the brightness of LED-based lighting devices, a plurality of LED-based lighting units are usually connected in series to form a LED-based lighting unit, and a plurality of LED-based lighting units can be further connected in series to form a lighting unit. device. The working voltage required for each lighting device usually depends on the forward voltage of the light-emitting diodes in the lighting unit, how many light-emitting diodes are in each lighting unit, how each lighting unit is connected to each other, and the How a lighting unit receives voltage from a power source in a lighting fixture.

Therefore, in most applications, some type of power voltage conversion device is required to convert the generally more common high voltage power supply to a lower voltage for supplying one or more LED-based lighting units . Because of the need for such a voltage conversion device, the efficiency of the lighting equipment based on the light-emitting diode is reduced, the cost is increased, and it is difficult to reduce its volume.

In order to improve the efficiency and reduce the size of the LED-based lighting device, many technologies have been developed so that the LED-based lighting device can use AC power such as 120V or 240V without a voltage conversion device. Generally, the LEDs in LED-based lighting devices are divided into a plurality of LED segments. Each LED segment can be selectively turned on and off as the AC voltage increases or decreases under the control of an associated switch or current source. All switches or current sources in the lighting device are controlled by a controller.

In the previous technology, most of the high-voltage LED-based lighting devices used to detect the voltage value of the input AC power supply or the current value flowing through the lighting device to control the switch or current source to select To switch LED segments on and off. For example, US Patent Nos. 6,989,807 and 8,324,840, and US Patent Publication No. 2011/0089844 all have an integral controller capable of detecting the voltage value of an input voltage to control a switch or a current source connected to a light emitting diode. US Patent Publications No. 2012/0056559 and No. 2012/0217887 use an integral controller to control the current limiter or switch according to the detected local current.

Since more and more light-emitting diode-based lighting units have been applied to high-brightness lighting equipment using high voltage, how to use the existing AC power on the wall to flexibly and effectively increase the utilization rate of light-emitting diodes, Design methods and apparatus for driving and connecting multiple LED-based lighting units that reduce power consumption and provide stability and high brightness have formed an indispensable need.

Contents of the invention

The invention is made to provide a device capable of using high voltage and efficiently driving light-emitting diode strings. According to the device provided by the present invention, a plurality of light emitting diodes are divided into a plurality of LED segments connected in series, and connected in series with a switching voltage detector and a current limiter.

Each light-emitting diode segment is connected in parallel with a switch, and there is a switch controller in the device that outputs binary code or non-binary code to turn on or off each parallel switch, so that the lighting device based on light-emitting diodes, Its operation mode can be changed as the voltage value of the input voltage changes.

In the first preferred embodiment of the present invention, the switching voltage detector is connected to the last LED segment, and the current limiter is connected between the switching voltage detector and the ground. The switching voltage detector includes a dropout detector for detecting the change of the input voltage, and a mode change signal generator for generating a mode change signal when the input voltage changes.

In the first preferred embodiment, the differential pressure detector includes three N-type voltage-controlled current limiters, and each N-type voltage-controlled current limiter has three terminals. In a first embodiment of the differential pressure detector, one or more light emitting diodes are connected between the first terminals of the first and second voltage controlled current limiters. One or more light emitting diodes are also connected between the first terminals of the second and third voltage-controlled current limiters.

The second terminal of each N-type voltage-controlled current limiter is connected to a bias voltage, and the third terminal is connected to a common node through a current sensor. The mode change signal generator has two comparators connected to the three current sensors, and a control signal generator receives the outputs of the two comparators and generates two mode change signals according to the change of the input voltage.

In the second type of fabrication of the differential pressure detector, the first terminal of each N-type voltage-controlled current limiter is connected to one terminal of a respective current sensor, and each two adjacent current sensors One or more LEDs are connected between the other ends of the device. The second terminal of each N-type voltage-controlled current limiter is connected to a bias voltage, and the third terminal is connected to a common node.

There are three differential amplifiers respectively connected to the two ends of the three current sensors, the mode change signal generator has two comparators connected to the outputs of the three differential amplifiers, and a control signal generator receives the output of the two comparators output, and generates two mode change signals based on changes in the input voltage.

In a second preferred embodiment of the present invention, the switching voltage detector is connected to the leading LED segment, and the current limiter is connected between the input voltage and the switching voltage detector. The switching voltage detector includes a dropout detector for detecting the change of the input voltage, and a mode change signal generator for generating a mode change signal when the input voltage changes.

In the second preferred embodiment, the differential pressure detector includes three P-type voltage-controlled current limiters, and each P-type voltage-controlled current limiter has three terminals. In the first embodiment of the differential pressure detector, one or more light emitting diodes are connected between the first terminals of the first and second voltage controlled current limiters. One or more light-emitting diodes are also connected between the first terminals of the second and third voltage-controlled current limiters.

Each P-type voltage-controlled current limiter has a voltage source connected between its second terminal and the input voltage, and its third terminal is connected to a common node through a current sensor. The mode change signal generator has two comparators connected to the three current sensors, and a control signal generator receives the outputs of the two comparators and generates two mode change signals according to the change of the input voltage.

In the second type of fabrication example of the dropout voltage detector, the third terminal of each P-type voltage-controlled current limiter is directly connected to a common node, and the second terminal is connected to the input voltage via a voltage source, the first The terminals are connected to one end of each current sensor, and one or more LEDs are connected between the other ends of each two adjacent current sensors.

Similar to the second-type production example of the differential pressure detector in the first preferred embodiment, the second-type production example of the differential pressure detector in the second preferred embodiment also has three differential amplifiers respectively connected to three across the current sensor. The mode change signal generator has two comparators connected to the outputs of the three differential amplifiers, and a control signal generator receives the outputs of the two comparators and generates two mode change signals according to the change of the input voltage.

Description of drawings

1 is a block diagram showing an apparatus for driving LED strings with a high voltage according to a first preferred embodiment of the present invention;

FIG. 2 shows the voltage value V _IN of the input voltage of the light-emitting diode-based lighting device of the present invention, using rectified AC power, operating in M different lighting modes;

FIG. 3 shows an example of a switch controller including a ripple counter to generate binary code;

FIG. 4 shows another example of a switch controller including a ripple counter for generating binary code and a memory for converting the binary code into non-binary code;

FIG. 5(A) is a block diagram showing a first type fabrication example of the switching voltage detector in the first preferred embodiment of the present invention;

FIG. 5(B) is a block diagram showing a second type of manufacturing example of the switching voltage detector in the first preferred embodiment of the present invention;

Fig. 6 shows the characteristics of the current to voltage (I-V) of the voltage-controlled current limiter used to switch the three terminals of the N-type voltage detector in the first preferred embodiment;

Fig. 7 shows the signal waveforms of several signals in the mode change signal generator in the first preferred embodiment;

8 is a block diagram showing a device for driving LED strings with high voltage according to a second preferred embodiment of the present invention;

FIG. 9(A) is a block diagram showing a first-type manufacturing example of a switching voltage detector according to a second preferred embodiment of the present invention;

FIG. 9(B) is a block diagram showing a second fabrication example of the switching voltage detector of the second preferred embodiment of the present invention;

Fig. 10 shows the characteristics of the current to voltage (I-V) of the voltage-controlled current limiter used to switch the three terminals of the P-type in the differential pressure detector in the voltage detector in the second preferred embodiment;

FIG. 11 shows signal waveforms of several signals in the mode change signal generator in the second preferred embodiment.

Wherein, the reference signs are explained as follows:

100, 800 LED segments

110, 810 switch

120, 820 switch controller

130, 830 switching voltage detector

140, 840 current limiter

141, 841 resistance

301 Ripple Counter

302 switch driver

401 storage element

501, 501', 901, 901' differential pressure detector

502, 902 mode change signal generator

511, 512, 513, 911, 912, 913 current sensors

521, 523, 921, 923 Bias Voltage Switcher

531, 533, 931, 933 winding switch

541, 542, 941, 942 comparators

551, 552, 553, 951, 952, 953 current sensors

561, 562, 563, 961, 962, 963 differential amplifier

Detailed ways

This specification provides accompanying drawings, so that the present invention can be further understood, and the accompanying drawings also constitute a part of this specification. The drawings illustrate the embodiments of the invention and, together with the description, serve to explain the principles of the invention.

1 is a block diagram showing a device for driving light-emitting diode strings with a high voltage according to a first preferred embodiment of the present invention. The device of this embodiment includes a plurality of light-emitting diodes connected in series and divided into multiple LED segments 100, each LED segment 100 has a positive terminal and a negative terminal, respectively connected to the negative terminal of the preceding LED segment and the positive terminal of the following LED segment.

As shown in FIG. 1 , each LED segment 100 has a switch 110 connected in parallel thereto, and a switch controller 120 supplies a plurality of switching control signals to control the switches 110 . The negative end of a light-emitting diode segment at the end is connected to a switching voltage detector 130, and a current limiter 140 is connected between the switching voltage detector 130 and the ground. The current limiter 140 can also be connected by a resistor 141 to replace.

An input high voltage V _IN is connected to the leading LED segment and switch controller 120 to provide voltage to the entire device to drive all LEDs. The switch voltage detector 130 detects a voltage that varies with the input voltage V _IN to generate two mode change signals UP_P and DN_P to control the switch controller 120 . When the input voltage V _IN rises, the mode change signal UP_P generates a series of mode change pulses to change the state of the switch controller 120 . Similarly, when the input voltage V _IN drops, the mode change signal DN_P generates a series of mode change pulses to change the state of the switch controller 120 .

FIG. 2 shows the voltage values of the input voltage V _IN under M different operation modes for controlling the LED-based lighting device with two mode change signals UP_P and DN_P in the present invention. The input voltage is a rectified AC voltage, and different numbers of LED segments are connected in series in each operation mode. The two mode change signals UP_P and DN_P trigger the switch controller 120 to change state, so that the LED-based lighting device operates in different operation modes.

As shown in FIG. 2 , when the input voltage value V _IN increases from V _i to V _i +1 between times T _i and T _i+1 , the LED-based lighting device operates in mode-i. When the rectified input voltage reaches the maximum value V _IN(MAX) , the voltage starts to decrease. The LED-based lighting device operates in mode-M when the input voltage value is between V _M and V _IN(MAX) , and then operates again when the input voltage value falls between V _i and V _{i+ 1} in mode-i. The difference between the voltage values V _i and V _i+1 is the mode discrimination voltage ΔV.

FIG. 3 shows an example of the switch controller 120 in the first preferred embodiment of the present invention. In this example, the switch controller 120 includes a ripple counter 301 that generates binary codes. The output of the ripple counter 301 is connected to a plurality of switch drivers 302 to drive the plurality of switches 110 shown in FIG. 1 . Therefore, the LED-based lighting device of FIG. 1 can change the operation mode according to the binary code generated by the ripple counter 301 .

FIG. 4 shows another example of the switch controller 120 in the first preferred embodiment of the present invention. As shown in FIG. 4, in this example, a memory element 401 is connected to the output of the ripple counter 301, and the binary code generated by the ripple counter 301 is first converted into a non-binary code, and then connected to a plurality of switch drivers 302 . Therefore, the light-emitting diode-based lighting device of FIG. 1 can use non-binary codes to change the operation mode according to the coded correspondence stored in the storage element 401 .

As shown in FIG. 5(A), the first type of manufacturing example of the switching voltage detector 130 manufactured according to the first preferred embodiment of the present invention includes a voltage difference detector 501 and a mode change signal generator 502 . The differential voltage detector 501 includes three N-type voltage-controlled current limiters M ₁ , M ₂ , and M ₃ , each N-type voltage-controlled current limiter has three terminals. Between the first ends of M1 and _M2 , _one or more LEDs are connected in series. These LEDs can also be replaced by diodes having similar current versus voltage characteristics. Similarly, one or more light-emitting diodes are connected in series between the first ends _{of M2} and M3.

According to the present invention, the N-type voltage-controlled current limiter with three terminals can be manufactured by various semiconductor components. Although Figure 5(A) shows N-channel metal-oxide-semiconductor (NMOS) field-effect transistors, NPN bipolar junction transistors (BJTs) and N-type insulated gate bipolar transistors (IGBTs) are also available. To make an N-type voltage-controlled current limiter.

FIG. 6 shows the current versus voltage (IV) characteristics of an N-type voltage-controlled current limiter with three terminals in the present invention. When the voltage V _bc between the second terminal and the third terminal (terminals b and c) of the current limiter is less than or equal to the threshold voltage V _th of the N-type current limiter, the current limiter is closed, and the current The current I _a through the current limiter is zero.

When the voltage V _bc between the second terminal and the third terminal (terminal b and c) of the current limiter is greater than the threshold voltage V _th of the current limiter, and the first terminal and the third terminal (terminal When the voltage V _ac between a and c) is less than the saturation voltage V _sat of the N-type current limiter, the current limiter acts like a resistor. In other words, the current _Ia flowing through the current limiter is linearly proportional to the voltage _Vac .

It can be seen from Figure 6 that when the voltage V _bc is greater than the threshold voltage V _th of the current limiter, and the voltage V _ac is also greater than the saturation voltage V _sat of the current limiter, the voltage of the N-type three-terminal The controlled current limiter then forms a fixed current source, and the current I _a is a function of the voltage V _bc , that is to say I _a =f(V _bc ). It should be noted that the saturation voltage V _sat of the current limiter is also proportional to the voltage V _bc .

As shown in Figure 5(A), the second terminals of the three N-type voltage-controlled current limiters are respectively connected to three bias voltages V ₁ , V ₂ and V ₃ , when M ₁ , M ₂ and When M ₃ has the same characteristics, the preferred bias voltage should meet the condition of V ₁ <V ₂ <V ₃ . The third terminals of M ₁ , M ₂ and M ₃ are connected to a common node via three respective current sensors 511 , 512 and 513 . It should be noted that the bias voltages V ₁ and V ₃ of M ₁ and M ₃ are controlled by bias voltage switches 521 and 523 , respectively.

In the differential voltage detector 501 , the current sensor is used to determine whether the operation mode of the LED-based lighting device needs to be changed according to the voltage value of the input voltage V _IN . When only _M2 has current passing through, there is no need to switch control, and the operation mode remains unchanged.

When the current flowing through M3 is larger _than that flowing through _M2 , it means that the input voltage V _IN has increased to the point where more LEDs must be connected in series to withstand the higher voltage. Therefore, the mode change signal UP_P of the mode change signal generator 502 must generate a mode change pulse to change the operation mode of the LED-based lighting device. In addition, the mode change signal generator 502 also generates a wait signal to short _- circuit the bypass switch 533, so that no current flows through M3, and only _M2 has a current flow until the required LED segment after the operation mode is changed. have been concatenated.

On the contrary, when the current flowing through M ₁ is larger than that flowing through M ₂ , it means that the input voltage V _IN has been reduced to the point where fewer LEDs must be connected in series. Therefore, the mode change signal DN_P of the mode change signal generator 502 must generate a mode change pulse to change the operation mode of the LED-based lighting device.

The mode change signal generator 502 also generates a wait signal to short-circuit the bypass switch 531 so that no current flows through M ₁ and only M ₂ flows until the required LED segments have been switched off after the operating mode change. in series. It should be noted that the voltage V _com at the common node varies with the input voltage V _IN .

As mentioned above, the bias voltages _V1 and _{V3 of} M1 and _M3 are controlled by the bias voltage switches 521 and 523, respectively. It can be seen from FIG. 5(A) that after the operation mode is changed, the required LED sections have been connected in series, and when the change of the input voltage value must be detected again, the mode change signal generator 502 generates a detection signal, which will Bias voltages V ₁ and V ₃ are connected to M ₁ and M ₃ .

In the mode change signal generator 502, the first comparator 541 has two inputs connected to the current sensors 511 and 512, respectively. The second comparator 542 has two inputs connected to the current sensors 513 and 512 respectively. As shown in FIG. 5(A), the mode change signal generator 502 further includes a signal generator composed of two RS flip-flops, three delay circuits, and several logic gates.

The signal generator in the mode change signal generator 502 receives the outputs of the two comparators to generate a wait signal, a detection signal, and two mode change signals UP_P and DN_P. FIG. 7 shows signal waveforms of several signals in the mode change signal generator 502 . It can be seen from Fig. 5(A) that in the differential pressure detector 501, the _first terminal of M1 is connected to the last LED segment, and the common node V _com is connected to a current limiter in the whole device 140.

According to the first preferred embodiment of the present invention, FIG. 5(B) shows a second-type manufacturing example of the switching voltage detector 130, wherein the differential voltage detector 501' includes three N-type voltage _- controlled current limiters M1 , M ₂ and M ₃ , the first terminals of the three current sensors 551 , 552 and 553 are respectively connected to the first terminals of the three N-type voltage-controlled current limiters M ₁ , M ₂ and M ₃ . Between the second terminals of every two adjacent current sensors, one or more LEDs are connected in series.

Similar to the first type of production example, in the pressure difference detector of the second type of production example, the second terminals of the three N-type voltage-controlled current limiters are respectively connected to the three bias voltages V ₁ , V2 and _V3 , the third terminal of each N _- type voltage controlled current limiter, are directly connected to the common node. There are three differential amplifiers 561 , 562 and 563 respectively connected from the second terminals to the first terminals of the three current sensors 551 , 552 and 553 .

As shown in FIG. 5(B), the first comparator 541 receives the outputs of the differential amplifiers 561 and 562 , and the second comparator 542 receives the outputs of the differential amplifiers 563 and 562 . The mode change signal generator 502 of the second type production example shown in Fig. 5 (B) is the same as the first type production example of Fig. 5 (A), and the operating principle of the differential pressure detector 501' is also similar at the same time, so no longer Repeat instructions.

8 shows a block diagram of an apparatus for driving LED strings with a high voltage according to a second preferred embodiment of the present invention. The apparatus of this embodiment includes a plurality of LEDs connected in series and divided into a plurality of LEDs connected in series. LED segments 800, each LED segment 800 having a positive terminal and a negative terminal, each connected to the negative terminal of the preceding LED segment and the positive terminal of the following LED segment.

As shown in FIG. 8 , each LED segment 800 has a switch 810 connected in parallel thereto, and a switch controller 820 supplies a plurality of switching signals to control the switches 810 . In a second preferred embodiment, the negative terminal of the last LED segment is connected to ground.

An input high voltage V _IN provides voltage to drive all LEDs. A current limiter 840 is connected between the input voltage V _IN and the switching voltage detector 830 for detecting the voltage value of the input voltage V _IN , and generates two mode changing signals UP_P and DN_P to control the switching controller 820 . The current limiter 840 can also be replaced by a resistor 841 .

When the input voltage V _IN rises, the mode change signal UP_P generates a series of mode change pulses to change the state of the switch controller 820 . Similarly, when the input voltage V _IN drops, the mode change signal DN_P generates a series of mode change pulses to change the state of the switch controller 820 .

In the present invention, the switch controller 120 in the first preferred embodiment can also be used as the switch controller 820 in the second preferred embodiment. Similar to the first preferred embodiment, the switch controller 820 can generate binary codes with a ripple counter, or generate non-binary codes with a ripple counter and a code corresponding memory.

As shown in FIG. 9(A), the first type of switching voltage detector 830 manufactured according to the second preferred embodiment of the present invention includes a voltage difference detector 901 and a mode change signal generator 902 . The differential pressure detector 901 includes three P-type voltage-controlled current limiters M ₁ , M ₂ and M ₃ , and each P-type voltage-controlled current limiter has three terminals. Between the first ends of M1 and _M2 , _one or more LEDs are connected in series. Similarly, one or more light-emitting diodes are connected in series between the first ends _{of M2} and M3.

Although Figure 9(A) shows a P-type voltage-controlled current limiter made of a P-channel metal-oxide-semiconductor (PMOS) field-effect transistor, a PNP-type bipolar junction transistor (BJT) and a P-type insulated gate Bipolar transistors (IGBTs) can also be used to make P-type voltage-controlled current limiters.

FIG. 10 shows the current versus voltage (IV) characteristics of a P-type three-terminal voltage-controlled current limiter in the present invention. When the voltage V _cb between the third terminal and the second terminal (terminal c and b) of the current limiter is less than or equal to the threshold voltage V _th of the P-type current limiter, the current limiter is closed, and the current The current I _a through the current limiter is zero.

When the voltage V _cb between the third terminal and the second terminal (terminal c and b) of the current limiter is greater than the threshold voltage V _th of the current limiter, and the third terminal and the first terminal (terminal When the voltage V _ca between c and a) is smaller than the saturation voltage V _sat of the P-type current limiter, the current limiter acts like a resistor. In other words, the current _Ia flowing through the current limiter is linearly proportional to the voltage _Vca .

It can be seen from Figure 10 that when the voltage V _cb is greater than the threshold voltage V _th of the current limiter, and the voltage V _ca is also greater than the saturation voltage V _sat of the current limiter, the P-type voltage with three terminals The controlled current limiter then forms a fixed current source, and the current I _a is a function of the voltage V _cb , that is to say I _a =f(V _cb ). It should be noted that the saturation voltage V _sat of the current limiter is also proportional to the voltage V _cb .

As shown in Fig. 9(A), three voltage sources V ₁ , V ₂ and V ₃ are respectively connected between the input voltage V _IN and the second terminals of the three P-type voltage-controlled current limiters. When M _1. When M ₂ and M ₃ have the same characteristics, a better voltage source should meet the condition of V ₁ <V ₂ <V ₃ . The third terminals of M ₁ , M ₂ and M ₃ are connected to a common node via three respective current sensors 911 , 912 and 913 .

It can be seen from FIG. 9(A) that voltage sources V ₁ and V ₃ are connected to M ₁ and M ₃ through bias voltage switches 921 and 923 respectively. Moreover, in this fabrication, the bias voltages applied to the three PMOSs are respectively the voltage differences between the input voltage V _IN and the voltage sources V ₁ , V ₂ and V ₃ .

Similar to the first preferred embodiment, in the second preferred embodiment, the P-type voltage-controlled current limiters M ₁ and M ₃ with three terminals also have winding switches 931 and 933 connected to the respective second terminals and common nodes.

In the mode change signal generator 902, the first comparator 941 has two inputs connected to the current sensors 912 and 911, respectively. The second comparator 942 has two inputs connected to the current sensors 912 and 913 respectively. As shown in Figure 9 (A), the mode change signal generator 902 includes a signal generator composed of two RS flip-flops, three delay circuits, and several logic gates to generate waiting signals, detect signal, and two mode change signals UP_P and DN_P.

Those who are familiar with the field of the present invention should have understood the working principle of the differential pressure detector 901 in the second preferred embodiment and the mode change signal generator 902 from the above description, and the differential pressure detection in the first preferred embodiment The generator 501 and the mode change signal generator 502 are very similar, so the description will not be repeated here. FIG. 11 shows signal waveforms of several signals in the mode change signal generator 902 .

According to the second preferred embodiment of the present invention, FIG. 9(B) shows a second-type manufacturing example of the switching voltage detector 830, wherein the differential voltage detector 901' includes three P-type voltage _- controlled current limiters M1 , M ₂ and M ₃ , the third terminals of each P-type voltage-controlled current limiter, are directly connected to the common node. Similar to the first type of manufacturing example, three voltage sources V ₁ , V ₂ and V ₃ are respectively connected between the input voltage V _IN and the second terminals of the three P-type voltage-controlled current limiters.

In the second type of production example, the first terminals of the three current inductors 951, 952 and 953 are respectively connected to the first terminals of the _three P-type voltage _- controlled current limiters M1, _M2 and M3 . Between the second terminals of every two adjacent current sensors, one or more LEDs are connected in series. There are three differential amplifiers 961, 962 and 963 respectively connected from the first terminal to the second terminal of the three current sensors 951, 952 and 953.

As shown in FIG. 9(B), the first comparator 941 receives the outputs of the differential amplifiers 961 and 962 , and the second comparator 942 receives the outputs of the differential amplifiers 963 and 962 . The mode change signal generator 902 of the second type production example shown in Fig. 9 (B) is the same as the first type production example of Fig. 9 (A), and the working principle of the differential pressure detector 901' is also similar, so no longer Repeat instructions.

Although the present invention is described above by only a few preferred implementation examples, those who are familiar with the technical field can clearly understand that there are still many undescribed modifications and modifications, all without departing from the present invention defined below within the scope of the patent application.

Claims (20)

1. drive a device for multiple light-emitting diode, it is characterized in that, comprising:

Multiple light-emitting diode, is distinguished into multiple light-emitting diodes pipeline sections of series connection, and wherein each light-emitting diodes pipeline section has an anode, a negative terminal and a derailing switch to be parallel between this anode and this negative terminal;

One input voltage, is connected to the anode of a light-emitting diodes pipeline section leading in above-mentioned multiple light-emitting diodes pipeline section;

One switches voltage detector, first end is had to be connected to the negative terminal of a light-emitting diodes pipeline section of caudal end in above-mentioned multiple light-emitting diodes pipeline section, and produce first mode variable signal when above-mentioned input voltage rises, and produce the second patterns of change signal when above-mentioned input voltage declines;

One demand limiter, its first end is connected to the second end of above-mentioned switched voltage detector, and its second end ground connection; And

One on-off controller, receives above-mentioned input voltage, above-mentioned first and second patterns of change signals, and produces multiple switch-over control signal, distinctly control above-mentioned multiple light-emitting diodes pipeline section.

2. device as claimed in claim 1, it is characterized in that, above-mentioned demand limiter is a resistance.

3. device as claimed in claim 1, it is characterized in that, above-mentioned on-off controller comprises again:

One ripple counter, receives above-mentioned first and second patterns of change signals, and produces the output of multiple counter; And

Multiple switch driver, receives above-mentioned multiple counter and exports, and produce above-mentioned multiple switch-over control signal;

Wherein, above-mentioned multiple counter exports as binary code.

4. device as claimed in claim 1, it is characterized in that, above-mentioned on-off controller comprises again:

One ripple counter, receives above-mentioned first and second patterns of change signals, and produces first group of multiple output;

One memory element, receives above-mentioned first group of multiple output, and converts above-mentioned first group of multiple output to second group of multiple output; And

Multiple switch driver, receives above-mentioned second group of multiple output, and produces above-mentioned multiple switch-over control signal;

Wherein, above-mentioned first group of multiple output is binary code, and second group of multiple output is non-binary code.

5. device as claimed in claim 1, it is characterized in that, above-mentioned switched voltage detector comprises again a pressure detector and a patterns of change signal generator, and wherein pressure detector comprises:

First voltage-controlled demand limiter, wherein there is the first end points, the second end points is had to be connected to the first bias voltage via the first bias voltage derailing switch, there is the 3rd end points to be connected to a common node via the first current inductor, and be connected to the solderless wrapped connection derailing switch between this second end points and this common node;

Second voltage-controlled demand limiter, wherein has the first end points, has the second end points to be connected to the second bias voltage, has the 3rd end points to be connected to above-mentioned common node via the second current inductor;

The demand limiter that tertiary voltage controls, wherein there is the first end points, the second end points is had to be connected to the 3rd bias voltage via the 3rd bias voltage derailing switch, there is the 3rd end points to be connected to above-mentioned common node via the 3rd current inductor, and be connected to the solderless wrapped connection derailing switch between the second end points of the demand limiter that this tertiary voltage controls and above-mentioned common node;

One or more light-emitting diode, between the first end points being connected on above-mentioned first and second voltage-controlled demand limiters; And

One or more light-emitting diode, be connected on above-mentioned second and tertiary voltage control demand limiter the first end points between;

And above-mentioned mode signal generator comprises:

First comparator, has first input end to be connected to the 3rd end points of above-mentioned first voltage-controlled demand limiter, has the second input to be connected to the 3rd end points of above-mentioned second voltage-controlled demand limiter, and produces the first comparator output;

Second comparator, has first input end to be connected to the 3rd end points of the demand limiter that above-mentioned tertiary voltage controls, has the second input to be connected to the 3rd end points of above-mentioned second voltage-controlled demand limiter, and produces the second comparator output; And

One control signal generator, receives above-mentioned first and second comparators and exports, and produce above-mentioned first and second patterns of change signals;

Wherein, first end points of above-mentioned first voltage-controlled demand limiter, be connected to the negative terminal of the light-emitting diodes pipeline section of above-mentioned caudal end, above-mentioned common node is connected to the first end of above-mentioned demand limiter, and above-mentioned patterns of change signal generator, produce a waiting signal to control two solderless wrapped connection derailing switches in above-mentioned pressure detector, produce a detection signal to control two bias voltage derailing switches in above-mentioned pressure detector.

6. device as claimed in claim 5, it is characterized in that, above-mentioned on-off controller comprises again:

One ripple counter, receives above-mentioned first and second patterns of change signals, and produces the output of multiple counter; And

Multiple switch driver, receives above-mentioned multiple counter and exports, and produce above-mentioned multiple switch-over control signal;

Wherein, above-mentioned multiple counter exports as binary code.

7. device as claimed in claim 5, it is characterized in that, above-mentioned on-off controller comprises again:

One ripple counter, receives above-mentioned first and second patterns of change signals, and produces first group of multiple output;

One memory element, receives above-mentioned first group of multiple output, and converts above-mentioned first group of multiple output to second group of multiple output; And

Multiple switch driver, receives above-mentioned second group of multiple output, and produces above-mentioned multiple switch-over control signal;

Wherein, above-mentioned first group of multiple output is binary code, and second group of multiple output is non-binary code.

8. device as claimed in claim 5, is characterized in that, above-mentioned first, second, and third voltage-controlled demand limiter is a N-type metal oxide semiconductcor field effect transistor, bipolar npn junction transistor or N-type insulation lock bipolar transistor.

9. device as claimed in claim 1, it is characterized in that, above-mentioned switched voltage detector comprises again a pressure detector and a patterns of change signal generator, and wherein pressure detector comprises:

First voltage-controlled demand limiter, the first end points is wherein had to be connected to the first end of the first current inductor, the second end points is had to be connected to the first bias voltage via the first bias voltage derailing switch, there is the 3rd end points to be connected to a common node, and be connected to the solderless wrapped connection derailing switch between this second end points and this common node;

Second voltage-controlled demand limiter, wherein has the first end points to be connected to the first end of the second current inductor, has the second end points to be connected to the second bias voltage, has the 3rd end points to be connected to above-mentioned common node;

The demand limiter that tertiary voltage controls, the first end points is wherein had to be connected to the first end of the 3rd current inductor, the second end points is had to be connected to the 3rd bias voltage via the 3rd bias voltage derailing switch, there is the 3rd end points to be connected to above-mentioned common node, and be connected to the solderless wrapped connection derailing switch between the second end points of the demand limiter that this tertiary voltage controls and above-mentioned common node;

First differential amplifier, has two inputs to be distinctly connected to the second end and the first end of above-mentioned first current inductor;

Second differential amplifier, has two inputs to be distinctly connected to the second end and the first end of above-mentioned second current inductor;

3rd differential amplifier, has two inputs to be distinctly connected to the second end and the first end of above-mentioned 3rd current inductor;

One or more light-emitting diode, between the second end being connected on above-mentioned first and second current inductors; And

One or more light-emitting diode, be connected on above-mentioned second and the 3rd current inductor the second end between;

And above-mentioned mode signal generator comprises:

First comparator, has first input end to be connected to the output of above-mentioned first differential amplifier, has the second input to be connected to the output of above-mentioned second differential amplifier, and produces the first comparator output;

Second comparator, has first input end to be connected to the output of above-mentioned 3rd differential amplifier, has the second input to be connected to the output of above-mentioned second differential amplifier, and produces the second comparator output; And

One control signal generator, receives above-mentioned first and second comparators and exports, and produce above-mentioned first and second patterns of change signals;

Wherein, second end of above-mentioned first current inductor, be connected to the negative terminal of the light-emitting diodes pipeline section of above-mentioned caudal end, above-mentioned common node is connected to the first end of above-mentioned demand limiter, and above-mentioned patterns of change signal generator, produce a waiting signal to control two solderless wrapped connection derailing switches in above-mentioned pressure detector, produce a detection signal to control two bias voltage derailing switches in above-mentioned pressure detector.

10. device as claimed in claim 9, is characterized in that, above-mentioned first, second, and third voltage-controlled demand limiter is a N-type metal oxide semiconductcor field effect transistor, bipolar npn junction transistor or N-type insulation lock bipolar transistor.

The device of 11. 1 kinds of multiple light-emitting diodes of driving, is characterized in that, comprising:

One input voltage;

Multiple light-emitting diode, is distinguished into multiple light-emitting diodes pipeline sections of series connection, and wherein each light-emitting diodes pipeline section has an anode, a negative terminal and a derailing switch to be parallel between this anode and this negative terminal;

One demand limiter, has first end to be connected to above-mentioned input voltage, and has the second end;

One switches voltage detector, first end is had to be connected to the second end of above-mentioned demand limiter, the second end is had to be connected to the anode of a light-emitting diodes pipeline section leading in above-mentioned multiple light-emitting diodes pipeline section, and produce first mode variable signal when above-mentioned input voltage rises, and produce the second patterns of change signal when above-mentioned input voltage declines; And

One on-off controller, receives above-mentioned input voltage, above-mentioned first and second patterns of change signals, and produces multiple switch-over control signal, distinctly controls above-mentioned multiple light-emitting diodes pipeline section.

12. devices as claimed in claim 11, it is characterized in that, above-mentioned demand limiter is a resistance.

13. devices as claimed in claim 11, it is characterized in that, above-mentioned on-off controller comprises again:

One ripple counter, receives above-mentioned first and second patterns of change signals, and produces the output of multiple counter; And

Multiple switch driver, receives above-mentioned multiple counter and exports, and produce above-mentioned multiple switch-over control signal;

Wherein, above-mentioned multiple counter exports as binary code.

14. devices as claimed in claim 11, it is characterized in that, above-mentioned on-off controller comprises again:

One ripple counter, receives above-mentioned first and second patterns of change signals, and produces first group of multiple output;

One memory element, receives above-mentioned first group of multiple output, and converts above-mentioned first group of multiple output to second group of multiple output; And

Multiple switch driver, receives above-mentioned second group of multiple output, and produces above-mentioned multiple switch-over control signal;

Wherein, above-mentioned first group of multiple output is binary code, and second group of multiple output is non-binary code.

15. devices as claimed in claim 11, is characterized in that, above-mentioned switched voltage detector comprises again a pressure detector and a patterns of change signal generator, and wherein pressure detector comprises:

First voltage-controlled demand limiter, wherein there is the first end points, the second end points is had to be connected to the first voltage source via the first bias voltage derailing switch, the 3rd end points is had to be connected to a common node via the first current inductor, and the solderless wrapped connection derailing switch be connected between this second end points and this common node, this first voltage source is connected between above-mentioned input voltage and this first bias voltage derailing switch;

Second voltage-controlled demand limiter, wherein there is the first end points, the second end points is had to be connected to the second voltage source, have the 3rd end points to be connected to above-mentioned common node via the second current inductor, this second voltage source is connected between the second end points of above-mentioned input voltage and this second voltage-controlled demand limiter;

The demand limiter that tertiary voltage controls, wherein there is the first end points, the second end points is had to be connected to tertiary voltage source via the 3rd bias voltage derailing switch, the 3rd end points is had to be connected to above-mentioned common node via the 3rd current inductor, and the solderless wrapped connection derailing switch be connected between the second end points of the demand limiter that this tertiary voltage controls and above-mentioned common node, this tertiary voltage source is connected between above-mentioned input voltage and the 3rd bias voltage derailing switch;

One or more light-emitting diode, between the first end points being connected on the above-mentioned second and first voltage-controlled demand limiter; And

One or more light-emitting diode, be connected on the above-mentioned 3rd and second voltage-controlled demand limiter the first end points between;

And above-mentioned mode signal generator comprises:

First comparator, has first input end to be connected to the 3rd end points of above-mentioned second voltage-controlled demand limiter, has the second input to be connected to the 3rd end points of above-mentioned first voltage-controlled demand limiter, and produces the first comparator output;

Second comparator, has first input end to be connected to the 3rd end points of above-mentioned second voltage-controlled demand limiter, has the second input to be connected to the 3rd end points of the demand limiter that above-mentioned tertiary voltage controls, and produces the second comparator output; And

One control signal generator, receives above-mentioned first and second comparators and exports, and produce above-mentioned first and second patterns of change signals;

Wherein, first end points of above-mentioned first voltage-controlled demand limiter, be connected to the anode of leading above-mentioned light-emitting diodes pipeline section, above-mentioned common node is connected to the second end of above-mentioned demand limiter, and above-mentioned patterns of change signal generator, produce a waiting signal to control two solderless wrapped connection derailing switches in above-mentioned pressure detector, produce a detection signal to control two bias voltage derailing switches in above-mentioned pressure detector.

16. devices as claimed in claim 15, it is characterized in that, above-mentioned on-off controller comprises again:

One ripple counter, receives above-mentioned first and second patterns of change signals, and produces the output of multiple counter; And

Multiple switch driver, receives above-mentioned multiple counter and exports, and produce above-mentioned multiple switch-over control signal;

Wherein, above-mentioned multiple counter exports as binary code.

17. devices as claimed in claim 15, it is characterized in that, above-mentioned on-off controller comprises again:

One ripple counter, receives above-mentioned first and second patterns of change signals, and produces first group of multiple output;

One memory element, receives above-mentioned first group of multiple output, and converts above-mentioned first group of multiple output to second group of multiple output; And

Multiple switch driver, receives above-mentioned second group of multiple output, and produces above-mentioned multiple switch-over control signal;

Wherein, above-mentioned first group of multiple output is binary code, and second group of multiple output is non-binary code.

18. devices as claimed in claim 15, is characterized in that, above-mentioned first, second, and third voltage-controlled demand limiter is a P-type mos field-effect transistor, positive-negative-positive bipolar junction transistor or P type insulation lock bipolar transistor.

19. devices as claimed in claim 11, is characterized in that, above-mentioned switched voltage detector comprises again a pressure detector and a patterns of change signal generator, and wherein pressure detector comprises:

First voltage-controlled demand limiter, the first end points is wherein had to be connected to the first end of the first current inductor, the second end points is had to be connected to the first voltage source via the first bias voltage derailing switch, the 3rd end points is had to be connected to a common node, and the solderless wrapped connection derailing switch be connected between this second end points and this common node, this first voltage source is connected between above-mentioned input voltage and this first bias voltage derailing switch;

Second voltage-controlled demand limiter, the first end points is wherein had to be connected to the first end of the second current inductor, the second end points is had to be connected to the second voltage source, have the 3rd end points to be connected to above-mentioned common node, this second voltage source is connected between the second end points of above-mentioned input voltage and this second voltage-controlled demand limiter;

The demand limiter that tertiary voltage controls, the first end points is wherein had to be connected to the first end of the 3rd current inductor, the second end points is had to be connected to tertiary voltage source via the 3rd bias voltage derailing switch, the 3rd end points is had to be connected to above-mentioned common node, and the solderless wrapped connection derailing switch be connected between the second end points of the demand limiter that this tertiary voltage controls and above-mentioned common node, this tertiary voltage source is connected between above-mentioned input voltage and the 3rd bias voltage derailing switch;

First differential amplifier, has two inputs to be distinctly connected to first end and second end of above-mentioned first current inductor;

Second differential amplifier, has two inputs to be distinctly connected to first end and second end of above-mentioned second current inductor;

3rd differential amplifier, has two inputs to be distinctly connected to first end and second end of above-mentioned 3rd current inductor;

One or more light-emitting diode, between the second end being connected on above-mentioned first and second current inductors; And

One or more light-emitting diode, be connected on above-mentioned second and the 3rd current inductor the second end between;

And above-mentioned mode signal generator comprises:

First comparator, has first input end to be connected to the output of above-mentioned first differential amplifier, has the second input to be connected to the output of above-mentioned second differential amplifier, and produces the first comparator output;

Second comparator, has first input end to be connected to the output of above-mentioned 3rd differential amplifier, has the second input to be connected to the output of above-mentioned second differential amplifier, and produces the second comparator output; And

One control signal generator, receives above-mentioned first and second comparators and exports, and produce above-mentioned first and second patterns of change signals;

Wherein, second end of above-mentioned first current inductor, be connected to the anode of leading above-mentioned light-emitting diodes pipeline section, above-mentioned common node is connected to the second end of above-mentioned demand limiter, and above-mentioned patterns of change signal generator, produce a waiting signal to control two solderless wrapped connection derailing switches in above-mentioned pressure detector, produce a detection signal to control two bias voltage derailing switches in above-mentioned pressure detector.

20. devices as claimed in claim 19, is characterized in that, above-mentioned first, second, and third voltage-controlled demand limiter is a P-type mos field-effect transistor, positive-negative-positive bipolar junction transistor or P type insulation lock bipolar transistor.