CN108347809B - An LED driving circuit compatible with electronic ballast - Google Patents

Abstract

The present invention discloses an LED driving circuit compatible with an electronic ballast, the circuit comprising: a first filament circuit, for receiving a first voltage signal through an electronic ballast and converting it into a second voltage signal, outputting it to a first rectifier circuit; a second filament circuit, for receiving a first voltage signal through an electronic ballast and converting it into a third voltage signal, outputting it to an isolation circuit; an isolation circuit, for controlling a relay according to the third voltage signal to form a fourth voltage signal, outputting it to the first rectifier circuit; and a first rectifier circuit, for rectifying and filtering the second voltage signal and the third voltage signal to form pulsating direct current. The driving circuit provided in the embodiment of the present invention realizes electrical isolation between the first filament circuit and the second filament circuit through a relay, which can reduce the complexity of the circuit structure and has low cost.

Description

An LED driving circuit compatible with electronic ballast

Technical Field

The embodiments of the present invention relate to the technical field of light emitting diode (LED) lighting, and in particular to an LED driving circuit compatible with an electronic ballast.

Background Art

At present, the existing LED constant current source is directly connected to the electronic ballast. Since the signal output by the output end of the electronic ballast is a high-frequency AC signal, when the electronic ballast matches the fluorescent lamp to work normally, the high-frequency AC voltage output by the electronic ballast is as high as 380-600V/25-80KHz. The high-frequency AC voltage is directly connected to the LED module, which will cause the LED lamp tube to be broken down by the high voltage and the constant current source in the LED drive circuit to be burned out.

In order to solve the above problems, the LED light source driving control circuit commonly used at present includes: an input circuit and a switching circuit, wherein the input circuit includes two groups of filament circuits and a rectifier circuit, and the two groups of filament circuits receive the high-frequency AC signal output by the electronic rectifier, and output it to the switching circuit after rectification by the rectifier circuit, and obtain the voltage signal required by the LED through the switching circuit. However, in order to make the contact current protection of the two groups of filament circuits meet the IEC62776 safety regulations and certification standards, an isolation circuit must be installed between the two groups of filament circuits. However, the existing isolation circuit usually requires two relays to achieve electrical isolation between the two groups of filament circuits, so that the contact current protection meets the IEC62776 safety regulations and certification standards. It uses many components, the circuit structure is more complex, and the cost is higher.

Summary of the invention

The present invention provides an LED driving circuit compatible with an electronic ballast, which can reduce the complexity of the circuit structure and has a low cost.

The embodiment of the present invention provides an LED driving circuit compatible with an electronic ballast, comprising: an input circuit and an isolation circuit; wherein the input circuit comprises: a first filament circuit, a second filament circuit and a first rectifier circuit; the isolation circuit comprises: a relay;

The first filament circuit is used to receive the first voltage signal through the electronic ballast and convert it into a second voltage signal, and output it to the first rectifier circuit;

The second filament circuit is used to receive the first voltage signal through the electronic ballast and convert it into a third voltage signal, and output it to the isolation circuit;

The isolation circuit is used to control the relay to form a fourth voltage signal according to the third voltage signal, and output the fourth voltage signal to the first rectifier circuit;

The first rectifier circuit is used to rectify and filter the second voltage signal and the third voltage signal to form pulsating direct current.

The LED driving circuit compatible with electronic ballast provided in the embodiment of the present invention comprises a first filament circuit, which is used to receive a first voltage signal through the electronic ballast and convert it into a second voltage signal, which is output to the first rectifier circuit; a second filament circuit, which is used to receive a first voltage signal through the electronic ballast and convert it into a third voltage signal, which is output to the isolation circuit; an isolation circuit, which is used to control a relay according to the third voltage signal to form a fourth voltage signal, which is output to the first rectifier circuit; and a first rectifier circuit, which is used to rectify and filter the second voltage signal and the third voltage signal to form pulsating direct current. The driving circuit provided in the embodiment of the present invention realizes electrical isolation between the first filament circuit and the second filament circuit through a relay, which can reduce the complexity of the circuit structure and has low cost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a block diagram of a LED driving circuit compatible with an electronic ballast in Embodiment 1 of the present invention;

FIG2 is a block diagram of a LED driving circuit compatible with an electronic ballast in Embodiment 1 of the present invention;

FIG. 3 is a circuit diagram of an LED driving circuit compatible with an electronic ballast in a second embodiment of the present invention.

DETAILED DESCRIPTION

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

Embodiment 1

Figure 1 is a structural block diagram of an LED driving circuit compatible with an electronic ballast provided in Example 1 of the present invention. This embodiment can be applied to driving LED lamp tubes. As shown in Figure 1, the LED driving circuit compatible with an electronic ballast mainly includes: an input circuit 10 and an isolation circuit 20; wherein, the input circuit includes: a first filament circuit 101, a second filament circuit 102 and a first rectifier circuit 103; the isolation circuit 20 includes: a relay.

The electronic ballast 30 is connected to a mains power supply, and the mains power supply is converted into a first voltage signal and a second voltage signal after passing through the electronic ballast 30 , wherein the first voltage signal and the second voltage signal are high-frequency voltage signals.

The first filament circuit 101 is used to receive the first voltage signal through the electronic ballast 30 and convert it into a second voltage signal, and output it to the first rectifier circuit 103. The first filament circuit 101 performs impedance matching between the first voltage signal and the LED load. The second filament circuit 102 is used to receive the first voltage signal through the electronic ballast 30 and convert it into a third voltage signal, and output it to the isolation circuit 20; the second filament circuit 102 performs impedance matching between the second voltage signal and the LED load. The isolation circuit 20 is used to control the relay 201 according to the third voltage signal to form a fourth voltage signal, and output it to the first rectifier circuit 103. The first rectifier circuit 103 is used to rectify and filter the second voltage signal and the fourth voltage signal to form a pulsating direct current.

Figure 2 is a structural block diagram of the LED driving circuit compatible with the electronic ballast in Example 1 of the present invention. As shown in Figure 2, the input circuit 10 also includes: a second rectifier circuit 104; wherein, the first input end of the second rectifier circuit 104 is connected to the output end of the first filament circuit 101, and the second input end of the second rectifier circuit 104 is connected to the output end of the second filament circuit 102, and is used to rectify and filter the second voltage signal and the third voltage signal to form a fifth voltage signal, and output it to the isolation circuit 20.

Furthermore, the input circuit 10 also includes: a voltage stabilizing circuit 105, which is used to keep the fifth voltage signal output by the second rectifier circuit 104 constant; wherein the input end of the voltage stabilizing circuit 105 is connected to the output end of the second rectifier circuit 104; and the output end of the voltage stabilizing circuit 105 is connected to the isolation circuit 20.

Furthermore, the input circuit 1 further includes: a first fuse 106 and a second fuse 107, and the output end of the first filament circuit 101 is connected to the first input end of the first rectifier circuit 103 through the first fuse 106. The output end of the second filament circuit 102 is connected to the first input end of the second rectifier circuit 105 through the second fuse 107. The first fuse 106 and the second fuse 107 are used for over-temperature protection to prevent the temperature inside the lamp holder from exceeding 125 degrees Celsius when the lamp tube is over-current. When the temperature exceeds 125 degrees Celsius, the first fuse 106 or the second fuse 107 is melted, thereby cutting off the input of the power supply, thereby protecting the electronic ballast and the LED lamp tube.

Furthermore, as shown in Figure 2, the LED driving circuit compatible with the electronic ballast also includes: a switching circuit 40 and an output circuit 50; the input end of the switching circuit 40 is connected to the output end of the first rectifier circuit 103, and the output end of the switching circuit 40 is connected to the input end of the output circuit 50; it is used to convert pulsating direct current into a seventh voltage signal with constant current; the output circuit 50 is connected to the load of the LED lamp, and is used to filter the seventh voltage signal and output an eighth voltage signal to drive the load of the LED lamp.

Furthermore, the isolation circuit 20 further includes: a first coupling capacitor 202 ; wherein a first end of the first coupling capacitor 202 is connected to a first input end of the first rectifier circuit 101 , and a second end of the first coupling capacitor 202 is connected to a first input end of the second rectifier circuit 104 .

The LED driving circuit compatible with electronic ballast provided in this embodiment comprises a first filament circuit, which is used to receive a first voltage signal through the electronic ballast and convert it into a second voltage signal, which is output to the first rectifier circuit; a second filament circuit, which is used to receive a first voltage signal through the electronic ballast and convert it into a third voltage signal, which is output to the isolation circuit; an isolation circuit, which is used to control a relay according to the third voltage signal to form a fourth voltage signal, which is output to the first rectifier circuit; and a first rectifier circuit, which is used to rectify and filter the second voltage signal and the third voltage signal to form pulsating direct current. The driving circuit provided in this embodiment realizes electrical isolation between the first filament circuit and the second filament circuit through a relay, which can reduce the complexity of the circuit structure and has low cost.

Embodiment 2

FIG3 is a circuit diagram of an LED driving circuit compatible with an electronic ballast in Embodiment 2 of the present invention. Based on the above embodiments, this embodiment further optimizes the LED driving circuit compatible with an electronic ballast. As shown in FIG3 , the input circuit includes a first filament circuit, a second filament circuit, a first rectifier circuit, a second rectifier circuit, and a voltage stabilizing circuit.

The electronic ballast 30 is connected to the mains power supply, that is, an industrial frequency voltage signal with a voltage of 220V and a frequency of 50HZ. The mains power supply is converted into a first voltage signal and a second voltage signal after passing through the electronic ballast 30, wherein the first voltage signal and the second voltage signal are high-frequency voltage signals.

The first filament circuit includes: a first simulated filament L1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, and a second capacitor C2; wherein the first end of the first simulated filament L1 is connected to the first output end of the electronic rectifier, and the second end of the first simulated filament L1 is connected to the second output end of the electronic rectifier; the first end of the first resistor R1 is respectively connected to the first end of the second resistor R2, the first end of the first capacitor C1, and the first end of the first simulated filament L1; the first end of the third resistor R3 is respectively connected to the first end of the fourth resistor R4, the first end of the second capacitor C2, and the second end of the first simulated filament L1; the second end of the first resistor R1 is respectively connected to the second end of the second resistor R2, the second end of the first capacitor C1, the second end of the third resistor R3, the second end of the fourth resistor R4, the second end of the second capacitor C2, and the first input end of the first rectifier circuit. The first filament circuit is used to receive the first voltage signal through the electronic ballast and convert it into a second voltage signal, which is output to the first rectifier circuit. Specifically, the first filament circuit is used to match the output voltage of the electronic rectifier with the impedance of the LED load, which can enhance the compatibility of the electronic ballast.

Furthermore, the output end of the first filament circuit is connected to the first input end of the first rectifier circuit through the first fuse F1.

The second filament circuit includes: a second simulated filament L2, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a tenth capacitor C10 and an eleventh capacitor C11; wherein, a first end of the second simulated filament L2 is connected to the third output end of the electronic rectifier, and a second end of the second simulated filament L2 is connected to the fourth output end of the electronic rectifier; a first end of the thirteenth resistor R13 is respectively connected to a first end of the fourteenth resistor R14, a first end of the tenth capacitor C10 and a first end of the second simulated filament L2; a first end of the fifteenth resistor R15 is respectively connected to a first end of the sixteenth resistor R16, a first end of the eleventh capacitor C11 and a second end of the second simulated filament L2; a second end of the thirteenth resistor R13 is respectively connected to a second end of the fourteenth resistor R14, a second end of the tenth capacitor C10, a second end of the fifteenth resistor R15, a second end of the sixteenth resistor R16, a second end of the eleventh capacitor C11 and a first input end of the second rectifier circuit. The second filament circuit is used to receive the first voltage signal through the electronic ballast and convert it into a third voltage signal, which is output to the second rectifier circuit. Specifically, the second filament circuit is used to match the output voltage of the electronic rectifier with the impedance of the LED load, which can enhance the compatibility of the electronic ballast.

Furthermore, the output end of the second filament circuit is connected to the first input end of the second rectifier circuit through the second fuse F2. The first fuse F1 and the second fuse F2 are used for over-temperature protection to prevent the temperature inside the lamp holder from exceeding 125 degrees Celsius when the lamp tube is over-current. When the temperature exceeds 125 degrees Celsius, the first fuse F1 or the second fuse F2 melts, thereby cutting off the input of the power supply, thereby protecting the electronic ballast and the LED lamp tube.

The first rectifier circuit includes: a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, an eighth capacitor C8, a seventeenth resistor R17 and an eighteenth resistor R18; wherein, the cathode of the first diode D1 is connected to the cathode of the second diode D2; the anode of the first diode D1 is connected to the cathode of the fourth diode D4 and the output end of the first filament circuit, the anode of the second diode D2 is connected to the cathode of the third diode D3 and the output end of the isolation circuit, and the anode of the third diode D3 is connected to the anode of the fourth diode D4; the first end of the eighth capacitor C8 is connected to the cathode of the second diode D2, and the second end of the eighth capacitor C8 is connected to the anode of the third diode D3; the first end of the seventeenth resistor R17 is connected to the first end of the eighteenth resistor R18, the second end of the seventeenth resistor R17 is connected to the anode of the third diode D3, and the other end of the resistor R13 is connected to the cathode of the diode D2.

The second rectifier circuit includes: a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8 and a ninth capacitor C9; wherein, the cathode of the fifth diode D5 is connected to the cathode of the sixth diode D6; the anode of the fifth diode D5 is connected to the cathode of the eighth diode D8 and the output end of the second filament circuit, the anode of the sixth diode D6 is connected to the cathode of the seventh diode D7 and the output end of the isolation circuit, and the anode of the seventh diode D7 is connected to the anode of the eighth diode D8; the first end of the ninth capacitor C9 is connected to the cathode of the sixth diode D6, and the second end of the ninth capacitor C9 is connected to the anode of the seventh diode D7.

The voltage stabilizing circuit includes: a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a first voltage stabilizing diode ZD1, a first field effect transistor M1 and a third capacitor C3; wherein, the first end of the fifth resistor R5 is respectively connected to the first end of the seventh resistor R7 and the first output end of the second rectifier circuit, and the second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6; the drain of the first field effect transistor M1 is connected to the second end of the seventh resistor R7, the gate of the first field effect transistor M1 is respectively connected to the second end of the sixth resistor R6 and the cathode of the first voltage stabilizing diode ZD1, and the source of the first field effect transistor M1 is connected to the first end of the third capacitor C3; the anode of the first voltage stabilizing diode ZD4 and the second end of the third capacitor C3 are respectively grounded.

Furthermore, the LED circuit also includes an isolation circuit, which includes a relay KT and a first coupling capacitor CY1; a first end of the first coupling capacitor CY1 is connected to a first input end of the first rectifier circuit, and a second end of the first coupling capacitor CY1 is connected to a first input end of the second rectifier circuit.

The relay includes six terminals, namely a first terminal K1, a second terminal K2, a third terminal K3, a fourth terminal K4, a fifth terminal K5 and a sixth terminal K6; the first terminal K1 is connected to the first output end of the voltage stabilizing circuit, the second terminal K2 is connected to the second output end of the voltage stabilizing circuit; the third terminal K3 is connected to the output end of the second filament circuit; the fourth terminal K4 is connected to the second input end of the first rectifier circuit; and the fifth terminal is connected to the sixth terminal.

Furthermore, a relay usually manufactured in an electrical scheme usually has 8 terminals, and in the embodiment of the present invention, only six of the terminals are used, and the remaining two terminals are suspended.

Furthermore, the normally open relay used in this embodiment. In the embodiment of the present invention, when all four output ends of the electronic ballast have high-frequency voltage signals output, the voltage signals output by the first output end and the second output end are sent to the first input end of the second rectifier circuit after passing through the first filament matching circuit and the first coupling capacitor, and the voltage signals output by the third output end and the fourth output end are sent to the second input end of the second rectifier circuit after passing through the second filament matching circuit. Both input ends of the second rectifier circuit can input voltage signals, and the voltage signals are rectified and filtered by the second rectifier circuit and stabilized by the voltage stabilizing circuit, and then the control relay KT is closed. At this time, the third terminal K3 and the fifth terminal K5 are closed, and the fourth terminal K4 and the sixth terminal K6 are closed. The voltage signal output by the output end of the second filament circuit enters the second input end of the first rectifier circuit through the third terminal K3, the fifth terminal K5, the fourth terminal K4 and the sixth terminal K6. When the two filament circuits output voltage signals to the second rectifier circuit at the same time, the relay KT is closed and the circuit is turned on. When any one of the two filament circuits cannot output a voltage signal to the second rectifier circuit, the relay KT is in a normally open state and cannot be attracted, and the circuit will not be turned on, thereby achieving the isolation effect, so that the contact current protection meets the IEC62776 safety regulations and certification standards.

The LED driving circuit compatible with the electronic ballast also includes: a switching circuit and an output circuit.

The switch circuit includes: a second voltage zener diode ZD2, a third voltage zener diode ZD3, a fourth voltage zener diode ZD4, an eighth resistor R8, a ninth resistor R9, a fourth capacitor C4, a tenth resistor R10, an eleventh resistor R11 and a first thyristor Q1; wherein the cathode of the second voltage zener diode ZD2 is connected to the first input circuit, the anode of the second voltage zener diode ZD2 is connected to the cathode of the third voltage zener diode ZD3, the anode of the third voltage zener diode ZD3 is connected to the cathode of the fourth voltage zener diode ZD4; the control of the first thyristor Q1 The electrodes are respectively connected to the first end of the eighth resistor R8, the first end of the ninth resistor R9 and the first end of the fourth capacitor C4, the cathode of the first thyristor Q1 is connected to the second end of the ninth resistor R9 and the second end of the fourth capacitor C4; the anode of the first thyristor Q1 is connected to the first end of the eleventh resistor R11, the second end of the eleventh resistor R11 is connected to the first end of the tenth resistor R10, the second end of the tenth resistor R10 and the cathode of the first thyristor Q1 are grounded respectively; the second end of the eighth resistor R8 is connected to the anode of the third zener diode ZD3.

The output circuit includes: a twelfth resistor R12, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7 and a first electrolytic capacitor CE1, wherein the first end of the twelfth resistor R12 is respectively connected to the first end of the fifth capacitor C5, the first end of the sixth capacitor C6, the first end of the seventh capacitor C7 and the positive electrode of the first electrolytic capacitor CE1; the second end of the twelfth resistor R12 is respectively connected to the second end of the fifth capacitor C5, the second end of the sixth capacitor C6, the second end of the seventh capacitor C7 and the negative electrode of the first electrolytic capacitor CE1; the positive electrode of the first electrolytic capacitor CE1 is connected to the positive electrode of the LED lamp, and the negative electrode of the first electrolytic capacitor CE1 is connected to the negative electrode of the LED lamp.

In the LED driving circuit compatible with electronic ballast provided in the embodiment of the present invention, a relay is used to realize the first filament circuit and the second filament circuit. When all four output ends of the electronic ballast have high-frequency voltage signals output, the voltage signals output by the first output end and the second output end are sent to the first input end of the second rectifier circuit after passing through the first filament matching circuit and the first coupling capacitor, and the voltage signals output by the third output end and the fourth output end are sent to the second input end of the second rectifier circuit after passing through the second filament matching circuit. Both input ends of the second rectifier circuit can input voltage signals, and the voltage signals are rectified and filtered by the second rectifier circuit and stabilized by the voltage stabilizing circuit, and then the relay is controlled to be attracted. At this time, the third terminal and the fifth terminal are closed, and the fourth terminal and the sixth terminal are closed. The voltage signal output by the output end of the second filament circuit enters the second input end of the first rectifier circuit through the third terminal, the fifth terminal, the fourth terminal and the sixth terminal. When the two filament circuits output voltage signals to the second rectifier circuit at the same time, the relay is attracted and the circuit is turned on. When any of the two filament circuits cannot output a voltage signal to the second rectifier circuit, the relay is in a normally open state and cannot be attracted, and the circuit will not be turned on, thereby achieving the effect of isolation, so that the contact current protection meets the IEC62776 safety regulations and certification standards. The complexity of the circuit structure can be reduced and the cost is low.

Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims (9)

1. An electronic ballast compatible LED driver circuit, comprising: an input circuit and an isolation circuit; wherein the input circuit comprises: the first filament circuit, the second filament circuit and the first rectifying circuit; the isolation circuit includes: a relay;

the first filament circuit is used for receiving a first voltage signal through the electronic ballast and converting the first voltage signal into a second voltage signal, and outputting the second voltage signal to the first rectifying circuit;

The second filament circuit is used for receiving the first voltage signal through the electronic ballast, converting the first voltage signal into a third voltage signal and outputting the third voltage signal to the isolation circuit;

the isolation circuit is used for controlling the relay to form a fourth voltage signal according to the third voltage signal and outputting the fourth voltage signal to the first rectifying circuit;

The first rectifying circuit is used for rectifying and filtering the second voltage signal and the third voltage signal to form pulsating direct current;

the input circuit further includes: a second rectifying circuit; wherein,

The first input end of the second rectifying circuit is connected with the output end of the first filament circuit, the second input end of the second rectifying circuit is connected with the output end of the second filament circuit, and the second rectifying circuit is used for rectifying and filtering the second voltage signal and the third voltage signal to form a fifth voltage signal, and outputting the fifth voltage signal to the isolation circuit;

when the first filament circuit and the second filament circuit simultaneously output voltage signals to the second rectifying circuit, the relay is attracted, and the circuit is conducted;

When any one of the two filament circuits cannot output a voltage signal to the second rectifying circuit, the relay is in a normally open state and cannot be attracted, and the circuit cannot be conducted.

2. The electronic ballast-compatible LED driver circuit of claim 1, the LED driving circuit compatible with the electronic ballast is characterized by further comprising: a switching circuit and an output circuit;

the input end of the switching circuit is connected with the output end of the first rectifying circuit, and the output end of the switching circuit is connected with the input end of the output circuit; a seventh voltage signal for converting the pulsating direct current into a constant current;

the output circuit is connected with the load of the LED lamp and is used for filtering the seventh voltage signal and outputting an eighth voltage signal to drive the load of the LED lamp.

3. The electronic ballast compatible LED driver circuit of claim 1, wherein said first filament circuit comprises: the first analog filament, the first resistor, the second resistor, the third resistor, the fourth resistor, the first capacitor and the second capacitor; wherein,

The first end of the first simulation filament is connected with the first output end of the electronic ballast, and the second end of the first simulation filament is connected with the second output end of the electronic ballast;

The first end of the first resistor is respectively connected with the first end of the second resistor, the first end of the first capacitor and the first end of the first simulation filament;

The first end of the third resistor is respectively connected with the first end of the fourth resistor, the first end of the second capacitor and the second end of the first simulated filament;

the second end of the first resistor is respectively connected with the second end of the second resistor, the second end of the first capacitor, the second end of the third resistor, the second end of the fourth resistor, the second end of the second capacitor and the first input end of the first rectifying circuit.

4. The electronic ballast compatible LED driver circuit of claim 1, wherein said isolation circuit further comprises: a first coupling capacitor; wherein,

The first end of the first coupling capacitor is connected with the first input end of the first rectifying circuit, and the second end of the first coupling capacitor is connected with the first input end of the second rectifying circuit.

5. The electronic ballast compatible LED driver circuit of claim 1, wherein said input circuit further comprises: the voltage stabilizing circuit is used for keeping the fifth voltage signal output by the second rectifying circuit constant; the input end of the voltage stabilizing circuit is connected with the output end of the second rectifying circuit; and the output end of the voltage stabilizing circuit is connected with the isolating circuit.

6. The electronic ballast-compatible LED driver circuit of claim 5, wherein said voltage stabilizing circuit comprises: the fifth resistor, the sixth resistor, the seventh resistor, the first zener diode, the first field effect transistor and the third capacitor; wherein,

The first end of the fifth resistor is connected with the first end of the seventh resistor and the first output end of the second rectifying circuit respectively, and the second end of the fifth resistor is connected with the first end of the sixth resistor;

The drain electrode of the first field effect transistor is connected with the second end of the seventh resistor, the grid electrode of the first field effect transistor is respectively connected with the second end of the sixth resistor and the cathode of the first zener diode, and the source electrode of the first field effect transistor is connected with the first end of the third capacitor;

the anode of the first zener diode and the second end of the third capacitor are grounded respectively.

7. The electronic ballast compatible LED driver circuit of claim 1, wherein said relay comprises six terminals, a first terminal, a second terminal, a third terminal, a fourth terminal, a fifth terminal, and a sixth terminal, respectively;

the first terminal is connected with a first output end of the voltage stabilizing circuit, and the second terminal is connected with a second output end of the voltage stabilizing circuit; the third terminal is connected with the output end of the second filament circuit; the fourth terminal is connected with the second input end of the first rectifying circuit; the fifth terminal is connected to the sixth terminal.

8. The electronic ballast-compatible LED driver circuit of claim 2, wherein said switching circuit comprises: the second voltage stabilizing diode, the third voltage stabilizing diode, the fourth voltage stabilizing diode, the eighth resistor, the ninth resistor, the fourth capacitor, the tenth resistor, the eleventh resistor and the first thyristor; wherein,

The cathode of the second zener diode is connected with the first rectifying circuit, the anode of the second zener diode is connected with the cathode of the third zener diode, and the anode of the third zener diode is connected with the cathode of the fourth zener diode;

the control electrode of the first thyristor is respectively connected with the first end of the eighth resistor, the first end of the ninth resistor and the first end of the fourth capacitor, and the cathode of the first thyristor is connected with the second end of the ninth resistor and the second end of the fourth capacitor; the anode of the first thyristor is connected with the first end of the eleventh resistor, the second end of the eleventh resistor is connected with the first end of the tenth resistor, and the second end of the tenth resistor and the cathode of the first thyristor are respectively grounded; and the second end of the eighth resistor is connected with the anode of the third zener diode.

9. The electronic ballast-compatible LED driver circuit of claim 2, wherein said output circuit comprises: a twelfth resistor, a fifth capacitor, a sixth capacitor, a seventh capacitor and a first electrolytic capacitor, wherein,

The first end of the twelfth resistor is respectively connected with the first end of the fifth capacitor, the first end of the sixth capacitor, the first end of the seventh capacitor and the anode of the first electrolytic capacitor;

The second end of the twelfth resistor is respectively connected with the second end of the fifth capacitor, the second end of the sixth capacitor, the second end of the seventh capacitor and the negative electrode of the first electrolytic capacitor;

the anode of the first electrolytic capacitor is connected with the anode of the LED lamp, and the cathode of the first electrolytic capacitor is connected with the cathode of the LED lamp.