WO2013078600A1

WO2013078600A1 - Led driving circuit and led driving chip

Info

Publication number: WO2013078600A1
Application number: PCT/CN2011/083090
Authority: WO
Inventors: 叶军; 高铭坤; 王莉
Original assignee: Ye Jun; Gao Mingkun; Wang Li
Priority date: 2011-11-29
Filing date: 2011-11-29
Publication date: 2013-06-06
Also published as: CN103329626A; CN103329626B

Abstract

Provided is an LED driving circuit, comprising a rectifying circuit (100), an LED power supply circuit (300) and an LED driving chip (200). The LED driving chip (200) can generate a current reference curve with the frequency at least two times of the frequency of an alternating current output by the rectifying circuit, and can control the LED power supply circuit (300) to provide a current with the same frequency as the current reference curve for an LED lamp. Further provided is an LED driving chip (200), which can generate a current reference curve with the frequency at least two times of the frequency of an input alternating current, and can control a peripheral circuit to provide a current with the same frequency as the current reference curve for an LED lamp. The LED driving circuit and the LED driving chip of the solution can restrain a current ripple output at a low frequency, and solve the problem of low frequency blink in a process of supplying power to an LED. The present invention is simple in design, low in the production cost, and high in work reliability.

Description

LED driver circuit and LED driver chip

The present invention relates to the field of LED technology, and more particularly to an LED driving circuit and an LED driving chip. Background technique

Current AC to DC (LED) drive circuits are available in single and two stages. The two-stage circuit output current has no low frequency ripple, but the cost is high. Low-cost single-stage AC-to-DC LED drive circuits have low-frequency ripple at the AC frequency after larger output rectification. For example, the AC frequency of the input AC to DC LED driver circuit is 100 Hz. If there is AC power with a frequency below 120 Hz in the AC power supplied to the LED, the LED lamp will flicker noise. This low-frequency flicker can be clearly seen with a device such as a cell phone or a video camera. If DC output is used, the power frequency ripple can be reduced to provide a smooth output to the LED lamp, but the circuit must be connected in parallel with a large capacity electrolytic capacitor for filtering.

However, the method of using DC output to power the LED lamp has the following problems: First, the LED power supply is generally integrated with the LED lamp, and the working environment temperature is very high. The electrolytic capacitor in the switching power supply is the most easily damaged component of the LED light source, and the electrolytic capacitor has a sharp decrease in life with increasing temperature. Therefore, the LED power supply using electrolytic capacitor filtering and DC output has a short life and unstable operation. At the same time, electrolytic capacitors have the defects of large volume, easy damage, temperature resistance and poor impact current resistance due to their own reasons. Electrolytic capacitors are one of the most vulnerable components in power electronics. Second, high voltage electrolytic capacitors will greatly increase the cost. Finally, the large-capacity capacitor has a large filter energy storage, and may have a large inrush current at the start-up time. Low reliability.

Chinese invention patent 201010622997.6 proposes an AC/DC variation method for eliminating power frequency ripple. The variation method is split into two power channels after the AC/DC conversion total power channel: the main power channel and the auxiliary power channel. The main power channel is a main power conversion unit, and the auxiliary power channel is sequentially an energy storage conversion unit, a storage capacitor and a valley conversion unit; the two power channels finally meet at the total output. However, this method is constructed using independent devices and is not highly integrated. Second, this method is more complicated and its components are more expensive. Can not achieve the purpose of universal application.

In summary, the prior art has the defects of complicated design, high production cost, poor work reliability, and short service life. It is desirable to provide an LED driving circuit and an LED driving chip capable of suppressing low-frequency output current ripple without relying on electrolytic capacitor rectification. Summary of the invention

The present invention is directed to the above-described drawbacks of the prior art, and provides an LED driving circuit and an LED driving chip capable of suppressing low-frequency output current ripple, having a simple design, low production cost, and high operational reliability.

The technical solution adopted by the present invention to solve the technical problem thereof is as follows: Providing an LED driving chip, comprising: sampling control for sampling an input alternating current and a voltage peak thereof and outputting a current reference curve having a frequency at least twice the input alternating current frequency The module receives the main-stage inductor series resistance voltage value of the peripheral driving circuit, receives the current reference curve output by the sampling control module, compares and outputs the main-stage inductor series resistance voltage value of the peripheral driving circuit and the corresponding voltage value on the current reference curve Comparator of the comparison result; a logic control module that receives the comparison result of the comparator output and outputs a duty cycle drive signal. In the LED driving chip of the present invention, the sampling control module includes: sampling an input alternating current and a voltage peak thereof to respectively generate a synchronization signal and a correction factor And output the input voltage correction module;

a reference module that provides a voltage reference source;

A correction factor and a synchronized signal output by the input voltage correction module and a voltage reference source provided by the reference module are received to generate a current ripple control module having a frequency reference curve having a frequency at least twice the input AC frequency.

The LED driving chip of the present invention further includes: a first pin connected to the input voltage correcting module, a second pin connected to the comparator, and a third pin connected to the logic control module.

The LED driving chip of the present invention further includes: a valley detecting module that monitors the peripheral driving circuit auxiliary inductance series resistance voltage and transmits the monitoring result to the logic control module, and a fourth pin connected to the valley detecting module.

Preferably, the chip further includes a protection module that provides overvoltage, overtemperature, and overcurrent protection for the logic control module.

An LED driving circuit is provided, including a rectifying circuit and an LED power supply circuit, wherein the LED power supply circuit includes a main-stage inductor connected to an output end of the rectifying circuit, a mutual inductance formed with the main-level inductor, and a sub-power supply for the LED lamp An inductor, a auxiliary inductor that forms a mutual inductance with the secondary inductor, a power tube, and a first resistor, wherein the power tube drain is connected to the main inductor, and the first resistor is connected to the power tube source The LED driving circuit further includes an LED driving chip, and the LED driving chip includes:

a sampling control module for sampling an alternating current outputted by the rectifier circuit and a voltage peak thereof and outputting a current reference curve having a frequency at least twice the input alternating current frequency;

Receiving the first resistance voltage value, receiving a current reference curve output by the sampling control module, comparing the first resistance voltage value with a corresponding voltage value on the current reference curve, and outputting a comparison result; A logic control module coupled to the power tube gate, receiving a comparison result of the comparator output, and outputting a duty cycle drive signal to control the power tube to be turned on and off.

In the LED driving circuit of the present invention, the LED power supply circuit further includes a capacitor connected in parallel with the secondary inductor, and a first diode connected to the secondary inductor and a cathode connected to the capacitor; the rectifier circuit Also included is a fourth resistor and a fifth resistor connected between the output of the rectifier circuit and the ground, the fourth resistor and the fifth resistor being connected in series.

In the LED driving circuit of the present invention, the sampling control module includes:

An input voltage correction module that samples a peak value of an alternating current voltage output from the rectifier circuit to generate a correction factor and outputs a signal synchronized with the alternating current output from the rectifier circuit and outputs the signal;

a reference module that provides a voltage reference source;

Receiving a correction factor and a synchronized signal output by the input voltage correction module and a voltage reference source provided by the reference module to generate a current ripple control module having a frequency reference curve at least twice the input AC frequency;

The LED driving chip further includes: a first pin, a second pin, and a third pin; wherein, the input voltage correcting module is connected to the node of the fourth resistor and the fifth resistor through the first pin, The comparator is connected to the node of the first resistor and the source of the power tube through the second pin, and the logic control module is connected to the gate of the power tube through the third pin.

In the LED driving circuit of the present invention, the LED driving chip further includes: a valley detecting module that monitors a third resistance voltage valley and outputs the monitoring result to the logic control module, a fourth pin, and/or is the logic control module Providing a protection module for overvoltage, overtemperature, and overcurrent protection; wherein the valley detecting module is connected to the nodes of the second resistor and the third resistor through the fourth pin.

The LED driving chip of the invention has the following beneficial effects: The sampling control module samples the input alternating current and its voltage peak and outputs a current having a frequency at least twice the input alternating current frequency. The reference curve, the comparison result of the comparator output received by the logic control module and outputting the duty cycle driving signal to drive the external circuit to provide the alternating current of the LED lamp with the frequency of the current reference curve, thereby fundamentally solving the low frequency flicker problem and suppressing The low-frequency output current ripple, and the need to provide electrolytic capacitors in the external circuit, the overall circuit design is simple, the generation cost is low, the work reliability is high, and the service life is long.

In addition, the LED driving chip comprises an input voltage correction module, a current ripple control module and a reference module, and the input voltage correction module samples the alternating current outputted by the rectifier circuit and the voltage peak thereof to generate a synchronization signal and a correction factor respectively, and output, current ripple The control module receives the correction factor and the synchronization signal generated by the input voltage correction module, and generates a current reference curve synchronized with the alternating current output from the rectifier circuit according to the voltage reference source provided by the reference module, so that different voltage effective values are input. , the output current value is the same.

The LED driving circuit of the invention has the following beneficial effects: the LED driving chip in the LED driving circuit generates a current reference curve having a frequency at least twice the output alternating current frequency of the rectifier circuit, and controls the LED power supply circuit to provide a current reference curve for the LED lamp The alternating frequency with the same frequency fundamentally solves the low-frequency flicker problem and suppresses the low-frequency output current ripple. Therefore, the LED driving circuit of the present invention does not need to provide an electrolytic capacitor, which makes the circuit design simple, the generation cost is low, the working reliability is high, and the use is high. long life.

In addition, the LED driving chip in the circuit comprises an input voltage correction module, a current ripple control module and a reference module, and the input voltage correction module samples the alternating current outputted by the rectifier circuit and the voltage peak thereof to generate a synchronization signal and a correction factor, respectively, and output, The current ripple control module receives the correction factor and the synchronization signal generated by the input voltage correction module, and generates a current reference curve synchronized with the alternating current output from the rectifier circuit according to the voltage reference source provided by the reference module, so that the input is different. The voltage rms value and the output current value are the same, so that the circuit drives the output current of the LED lamp The same is true for AC input with different voltage rms values. DRAWINGS

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

1 is a circuit diagram of a preferred embodiment of an LED driving circuit of the present invention;

2 is a corresponding diagram of an input AC voltage waveform, a current reference curve voltage waveform, a synchronization signal, and an AC current waveform of an LED driver circuit output load of the LED driving chip of the present invention;

3 is a schematic diagram of a correction curve when an alternating current frequency of the LED driving circuit of the present invention is 50 Hz and an effective voltage value is 220V;

Fig. 4 is a diagram showing the correspondence between the input AC voltage waveform, the current reference curve voltage waveform, the synchronization signal, and the AC current waveform of the LED drive circuit output load of the LED driving chip of the present invention when k = 2.

detailed description

The invention will be further explained below in conjunction with the drawings and embodiments.

In the first embodiment of the LED driving chip of the present invention, referring to FIG. 1, the LED driving chip 200 includes:

a sampling control module 210 that samples an input alternating current voltage peak and outputs a current reference curve having a frequency at least twice the input alternating current frequency;

Receiving the main-stage inductor series resistance voltage value of the peripheral driving circuit, receiving the current reference curve output by the sampling control module 210, comparing the main-stage inductor series resistance voltage value of the peripheral driving circuit with the corresponding voltage value on the current reference curve, and outputting the comparison result Comparator 220;

A logic control module that receives the comparison result output by the comparator 220 and outputs a duty cycle drive signal

240. In this embodiment, the input alternating current refers to an alternating current input from the peripheral driving circuit to the chip. The electric power, for example, is an alternating current output from a rectifying circuit in a peripheral driving circuit.

In this embodiment, the logic control module 240 outputs a duty cycle driving signal correspondingly according to the received comparison result of the comparator output and the preset time to drive the external circuit to provide the LED lamp with an alternating current frequency consistent with the current reference curve frequency. The fundamental low-frequency flicker problem is solved, the low-frequency output current ripple is suppressed, and the electrolytic circuit is not required in the external circuit, and the overall circuit design is simple, the generation cost is low, the work reliability is high, and the service life is long.

In a second embodiment of the LED driver chip of the present invention, referring to FIG. 1, the sampling control module 210 further includes:

An input voltage correction module 211 that samples the input alternating current and its voltage peaks to generate a synchronization signal and a correction factor, respectively;

Providing a reference module 212 of the voltage reference source;

The correction factor and the synchronized signal output by the input voltage correction module 211 and the voltage reference source provided by the reference module 212 are received to generate a current ripple control module 213 having a frequency reference curve at least twice the input AC frequency.

Referring to FIG. 2, a curve 400 is an AC voltage curve outputted by a rectifier circuit of a peripheral driving circuit, a curve 500 is a current reference curve generated by the current ripple control module 213, and a curve 600 is a synchronization signal output by the input voltage correction module 211, and a curve 800 is an alternating current current curve provided by the chip-controlled peripheral circuit for the LED. As can be seen from FIG. 2, the frequency of the current reference curve 500 is k times (k=2, 3, 4, . . . ) of the alternating current frequency outputted by the rectifier circuit of the peripheral driving circuit, that is, the current ripple control module 213 generates a frequency of at least The current reference curve 500, which is twice the input AC frequency, is selected by a preset to the current ripple control module 213. As can be seen from Fig. 2, the frequency of the alternating current current curve supplied to the LED for the peripheral circuit controlled by the chip coincides with the frequency of the current reference curve 500.

In this embodiment, the correction factor includes a first correction factor a and a second correction factor β, wherein the A correction factor a is determined by correcting the curve. The correction curve is shown in Fig. 3. It is completed by computer algorithm software. The peak range, frequency and output current value of the input voltage are input into the computer, and the correction curve can be calculated. The abscissa is the input peak voltage and the ordinate is the correction factor a. As shown in Fig. 3, the correction factor ranges from 0 < a < l. Each input peak voltage corresponds to a correction factor a. The second correction factor β is related to the k value, β = ί (k). When k=2, the current ripple control module 213 obtains a voltage reference value Vref, Vref=a*V according to the first correction factor a and the voltage value V of the voltage reference source provided by the reference module 212. When 1^3, the current ripple control module 213 obtains the voltage reference value Vref according to the first correction factor a, the second correction factor β, and the voltage value V of the voltage reference source provided by the reference module 212, Vref=a*β* V. The voltage expression of the current reference curve 500 generated by the current ripple control module 213 is: V (t) = Vref * F (k " t). The peripheral drive circuit controlled by the chip has an effective value of 85V at the input AC voltage. Within ~265V, a constant current is output to power the LEDs.

It should be noted that how to determine the specific voltage expressions of the first correction factor a, the second correction factor β, and the current reference curve 500 is prior art, and those skilled in the art can combine the voltage and current values according to the description in the present invention. The relevant knowledge of the correction obtains a voltage expression of the first correction factor a, the second correction factor β, and the corresponding current reference curve 500. Therefore, this is not explained in detail here.

In the embodiment, the LED driving chip 200 further includes: a first pin 260 connected to the input voltage correcting module 211, a second pin 270 connected to the comparator 220, and a third pin connected to the logic control module 240. 280.

In this embodiment, the rest of the situation is the same as the first embodiment of the LED driving chip of the present invention, and details are not described herein again. In other embodiments of the LED driver chip of the present invention, the LED driver chip 200 may also include other pins to connect the chip 200 to peripheral circuitry.

In the present embodiment, the rest of the case is the same as the first embodiment of the LED driving chip of the present invention. I will not repeat them here.

In a third embodiment of the LED driving chip of the present invention, referring to FIG. 1, the LED driving chip 200 further includes: a valley detecting module 230 that monitors the peripheral driving circuit auxiliary inductance series resistance voltage and transmits the monitoring result to the logic control module 240. And a fourth pin 290 connected to the valley detecting module 230.

In the present embodiment, the rest of the situation is the same as the second embodiment of the LED driving chip of the present invention, and details are not described herein again.

In a preferred embodiment of the invention, LED driver chip 200 includes a protection module 250 that provides overvoltage, overtemperature, and overcurrent protection for logic control module 240. The rest of the cases are the same as any of the first to third embodiments of the present invention, and will not be described again.

In the first embodiment of the LED driving circuit of the present invention, referring to FIG. 1, the LED driving circuit includes a rectifying circuit 100 and an LED power supply circuit 300. The LED power supply circuit 300 includes a main-stage inductor 301 connected to the output end of the rectifying circuit 100, and The main inductor 301 forms a secondary inductor 304 that is mutually inductive and supplies power to the LED lamp, an auxiliary inductor 305 that forms a mutual inductance with the secondary inductor 304, a power transistor 302, and a first resistor 303, wherein the power transistor 302 has a drain and a main inductor 301. Connected, the first resistor 303 is connected between the source of the power tube 302 and the ground; the LED driving circuit further includes an LED driving chip 200, and the LED driving chip comprises:

a sampling control module 210 that samples the alternating current output from the rectifier circuit 100 and its voltage peak and outputs a current reference curve having a frequency at least twice the input alternating current frequency;

Receiving a voltage value of the first resistor 303, receiving a current reference curve output by the sampling control module 210, comparing the voltage value of the first resistor 303 with a corresponding voltage value on the current reference curve, and outputting a comparison result of the comparator 220;

Connected to the gate of the power transistor 302, receives the comparison result output by the comparator 220, and outputs a duty cycle drive The motion signal is used to control the logic control module 240 that the power tube 302 is turned on and off.

In this embodiment, the LED driving circuit generates a current reference curve having a frequency at least twice the output alternating current frequency of the rectifier circuit through the LED driving chip therein, and controls the LED power supply circuit to provide the LED lamp with an alternating current frequency consistent with the current reference curve frequency, The low-frequency flicker problem is fundamentally solved, and the low-frequency output current ripple is suppressed. Therefore, there is no need to provide an electrolytic capacitor in the LED driving circuit of the present invention, which makes the circuit design simple, the generation cost is low, the work reliability is high, and the service life is long.

In the second embodiment of the LED driving circuit of the present invention, referring to FIG. 1, the LED power supply circuit 300 further includes a capacitor 309 connected in parallel with the secondary inductor 304, and a first electrode connected to the secondary inductor 304 and a negative electrode connected to the capacitor 309. Diode 308;

The rectifier circuit 100 further includes a fourth resistor 102 and a fifth resistor 103 connected between the output of the rectifier circuit 100 and ground, and the fourth resistor 102 and the fifth resistor 103 are connected in series.

In this embodiment, the rest of the situation is the same as the first embodiment of the LED driving circuit of the present invention, and details are not described herein again.

In the third embodiment of the LED driving circuit of the present invention, referring to FIG. 1, the LED driving chip 200 further includes:

A comparison result output by the comparator 220 is received and a duty cycle drive signal is output to drive the logic control module 240 with the power transistor 302 turned off and on.

In this embodiment, the logic control module 240 compares the output of the received comparator 220 according to the comparison. To turn off the power tube 302, the power tube 302 is turned on according to a preset time.

The rest of the situation is the same as the second embodiment of the LED driving circuit of the present invention, and details are not described herein again.

In a fourth embodiment of the LED driving circuit of the present invention, referring to FIG. 1, the sampling control module 210 includes:

An input voltage correction module 211 that samples the alternating current output from the rectifier circuit 100 and its voltage peaks to generate a synchronization signal and a correction factor, respectively, and outputs the same;

Providing a reference module 212 of the voltage reference source;

Receiving the correction factor and the synchronized signal output by the input voltage correction module 211 and the voltage reference source provided by the reference module 212 to generate a current ripple control module 213 having a frequency reference curve at least twice the input AC frequency;

The LED driver chip 200 further includes a first pin 260, a second pin 270, and a third pin 280. The input voltage correction module 211 is connected to the fourth resistor 102 and the fifth resistor 103 through the first pin 260. The node, the comparator 220 is connected to the first resistor 303 and the node of the source of the power transistor 302 through the second pin 270, and the logic control module 240 is connected to the gate of the power transistor 302 through the third pin 280. In this embodiment, the LED The comparator 220 of the driving chip 200 receives the voltage value of the first resistor 303 through the second pin 270, that is, the current value of the main inductor 301. If the voltage value exceeds the corresponding voltage value on the current reference curve sent by the current ripple control module 213, the comparator 213 transmits the comparison result to the logic control module 240, and the logic control module 240 compares and compares the third voltage through the third pin 280. As a result, the corresponding duty cycle drive signal output turns off the power transistor 302, and then the logic control module 240 outputs a corresponding duty cycle drive signal to turn on the power transistor 302 according to a preset time. Thus, the peak current of the main inductor 301 is in one-to-one correspondence with the current reference curve.

The voltage expression for the current reference curve has been implemented in the second implementation of the LED driver chip of the present invention. Given in the example. The following is an example of the voltage value expression of the current reference curve when k=2. It should be noted that the description is only for illustrative purposes and is not intended to limit the present invention. When k is set to 2, the current reference curve is twice the alternating current frequency of the input chip 200. The input alternating current circuit 100 has an alternating current frequency of 50 Hz and a voltage effective value of 220 volts. The correction curve at this time is as shown in FIG. Then, the output AC frequency is 100 Hz after the rectifier bridge 101 in the rectifier circuit, and the output AC voltage waveform is as shown by 410 in FIG. 4, and the signal generated by the input voltage correction module 211 synchronized with the AC 410 is as shown in FIG. The current reference curve generated by the current ripple control module 213 is shown as 510 in FIG. 4, and the current waveform of the primary inductor 301 and the current waveform on the load LED lamp are respectively shown in 710 and 810 of FIG. It can be seen that the alternating current frequency of the input rectifying circuit 100 is 50 Hz, and the alternating current frequency outputted to the load LED lamp by the LED driving circuit is 200 Hz, which fundamentally solves the problem that the alternating current of the frequency below 120 Hz is generated in the alternating current output to the load LED lamp. The LED light flashes and there is no need to set an electrolytic capacitor in the circuit.

The output voltage of the current reference curve 510 in one cycle is expressed as Vit) = η{2ωΐ) ² ^Vref

^ιη(2ωΐ) *Vref (t„t ₄ ; where Vref= a *V, F (k on) =sin (2 on) or sin (2 on) ² . Select the function sin in (tt ₃ ] 2 ω ΐ) ² *Vref is because the alternating current output from the rectifier circuit 100 is within this interval

The voltage value of 410 is large. In order to better protect the chip 200 and the components in the peripheral driving circuit controlled by the chip 200, the voltage expression of the current reference curve 510 in the interval (tt ₃ ) is selected as sin (2 ω ΐ). ² *Vref, allowing the voltage to change faster.

The preferred method of the current reference curve voltage expression is equally well available when k selects other values. In this embodiment, the other cases are the same as the third embodiment of the LED driving circuit of the present invention, and details are not described herein again. In other embodiments of the LED driving circuit of the present invention, the LED driving chip 200 can also Other pins are included to connect the chip 200 to peripheral circuitry.

In a fifth embodiment of the LED driving circuit of the present invention, referring to FIG. 1, the LED driving chip 200 further includes: a valley detecting module 230 that monitors a voltage drop of the third resistor 307 and outputs the monitoring result to the logic control module 240. The four-pin 290; wherein the valley detecting module 230 is connected to the node of the second resistor 306 and the third resistor 307 through the fourth pin 290.

In the present embodiment, the comparator 220 of the LED driving chip 200 receives the voltage value of the first resistor 303 through the second pin 270, that is, the current value of the main inductor 301. If the voltage value exceeds the corresponding voltage value on the current reference curve sent by the current ripple control module 213, the comparator 213 transmits the comparison result to the logic control module 240, and the logic control module 240 compares and compares the third voltage through the third pin 280. As a result, the corresponding duty cycle drive signal output turns off the power transistor 302.

After power transistor 302 is turned off, first diode 308 is forward conducting, secondary inductor 304 begins to supply current to capacitor 309 and the load (LED lamp), and the energy of the primary stage begins to be released to the secondary. After the energy of the secondary inductor 304 is released, the first diode 308 stops conducting. Main inductor 301 and power tube

The capacitor at the drain of 302 creates a resonance on the drain, and the auxiliary inductor 305 resonates at the same frequency. At the same time, the valley detecting module 230 of the LED driving chip 200 receives the voltage value of the second resistor 306 through the second pin 270, that is, the current value of the auxiliary inductor 305. When the voltage at the drain end of the power tube 302 reaches the bottom, the current of the auxiliary inductor 305 also reaches the lowest point at the same time. The valley detecting module 230 of the LED driving chip 200 monitors the voltage bottom value of the drain end of the power tube 302, and transmits the monitoring result to the bottom. The logic control module 240, the logic control module 240 outputs a duty cycle driving signal correspondingly through the fourth pin 290 to drive the power tube

302 opens. Thus, the current waveform of the main inductor 301 is as shown by 700 in FIG. The current waveform on the load LED is shown as 800 in Figure 2. It can be seen that the frequency of the current waveform of the output LED lamp coincides with the frequency of the current reference curve 500 generated by the current ripple control module 213.

In a preferred example of the LED driving circuit of the present invention, as shown in FIG. 1, the LED driving chip 200 Also included is a protection module 250 that provides overvoltage, overtemperature, and overcurrent protection for the logic control module 240. In the present preferred embodiment, the rest of the case is the same as the fifth embodiment of the LED driving circuit of the present invention, and details are not described herein again.

The LED driving circuit and the LED driving chip according to the present invention can be appropriately modified in a specific implementation process to suit the specific requirements of a specific situation. Therefore, it is to be understood that the specific embodiments of the present invention are intended to be illustrative only and not to limit the scope of the invention.

Claims

Rights request

An LED driving chip, comprising:

a sampling control module (210) that samples the input alternating current and its voltage peaks and outputs a current reference curve having a frequency at least twice the input alternating current frequency;

Receiving a main-stage inductor series resistance voltage value of the peripheral driving circuit, receiving a current reference curve output by the sampling control module (210), comparing a main-circuit inductor series resistance voltage value of the peripheral driving circuit with a corresponding voltage value on the current reference curve a comparator that outputs a comparison result (220);

A logic control module (240) that receives the comparison result output by the comparator (220) and outputs a duty cycle drive signal.

2. The LED driver chip according to claim 1, wherein the sampling control module (210) comprises:

An input voltage correction module (211) that samples the input alternating current and its voltage peaks to generate a synchronization signal and a correction factor, respectively, and outputs;

a reference module providing a voltage reference source (212);

Receiving a correction factor and a synchronized signal output by the input voltage correction module (211) and a voltage reference source provided by the reference module (212) to generate a current ripple control of a current reference curve having a frequency at least twice the input AC frequency Module (213).

3. The LED driving chip according to claim 2, wherein the chip further comprises: a first pin (260) connected to the input voltage correction module (211), and the comparator (220) a second pin (270) connected and a third pin (280) connected to the logic control module (240).

The LED driving chip of claim 1 , wherein the chip further comprises: monitoring a peripheral driving circuit auxiliary inductance series resistance voltage and transmitting the monitoring result to the logic control module A valley detecting module (230) of (240) and a fourth pin (290) connected to the valley detecting module (230).

5. The LED driver chip of claim 1, wherein the chip further comprises a protection module (250) that provides overvoltage, overtemperature, and overcurrent protection for the logic control module (240).

6. An LED driving circuit comprising a rectifier circuit (100) and an LED power supply circuit (300), the LED power supply circuit (300) comprising a main inductor (301) connected to an output end of the rectifier circuit (100), a secondary inductor (304) that forms a mutual inductance with the primary inductor (301) and supplies power to the LED lamp, an auxiliary inductor (305) that forms a mutual inductance with the secondary inductor (304), a power transistor (302), and a first a resistor (303), wherein the drain of the power tube (302) is connected to the main inductor (301), and the first resistor (303) is connected between the source of the power tube (302) and the ground The LED driving circuit further includes an LED driving chip (200), and the LED driving chip (200) includes:

a sampling control module (210) that samples the alternating current output from the rectifier circuit (100) and its voltage peak value and outputs a current reference curve having a frequency at least twice the input alternating current frequency;

Receiving the first resistor (303) voltage value, receiving a current reference curve output by the sampling control module (210), comparing the first resistor (303) voltage value with a corresponding voltage value on the current reference curve a comparator that outputs a comparison result (220);

a logic control module (240) coupled to the power tube (302) gate, receiving a comparison result of the comparator (220) output, and outputting a duty cycle drive signal to control the power tube (302) to be turned on and off .

The LED driving circuit according to claim 6, wherein the LED power supply circuit (300) further comprises a capacitor (309) connected in parallel with the secondary inductor (304), and a positive electrode and the secondary inductor. (304) a first diode (308) connected to the capacitor and connected to the capacitor (309);

The rectifier circuit (100) further includes a fourth resistor (102) and a fifth resistor (103) connected between the output end of the rectifier circuit (100) and the ground, the fourth resistor (102) and the fifth resistor (103) string Union.

8. The LED driving circuit according to claim 6, wherein the sampling control module (210) comprises:

An input voltage correction module (211) that samples the alternating current output from the rectifier circuit (100) and its voltage peak to generate a synchronization signal and a correction factor, respectively;

a reference module providing a voltage reference source (212);

9. The LED driving circuit according to claim 8, wherein the LED driving chip (200) further comprises: a first pin (260), a second pin (270), and a third pin (280) The input voltage correction module (211) is connected to the nodes of the fourth resistor (102) and the fifth resistor (103) through the first pin (260), and the comparator (220) passes through The second pin (270) is connected to the node of the first resistor (303) and the source of the power tube (302), and the logic control module (240) is connected to the power tube through the third pin (280) ( 302) The gate.

10. The LED driving circuit according to claim 9, wherein the LED driving chip (200) further comprises: monitoring a voltage drop of the third resistor (307) and outputting the monitoring result to the logic control module (240) a valley detection module (230), a fourth pin (290), and/or a protection module (250) that provides overvoltage, overtemperature, and overcurrent protection for the logic control module (240); wherein the valley detection The module (230) is connected to the node of the second resistor (306) and the third resistor (307) through the fourth pin (290).