CN103841697B - The IC chip and its control circuit of electric ballast direct drive LED - Google Patents

Abstract

The invention relates to an electronic ballast directly driving an IC chip of an LED and a control circuit thereof. The present invention can solve the problems of large power loss, short service life and air pollution in various lighting technologies driven by existing electronic ballasts. The key points of the technical scheme are: the IC chip includes input pins and output pins, and also includes a rectifier circuit , a no-load protection circuit and a constant current source circuit, the input end of the rectification circuit is connected to the input pin, the output end of the rectification circuit is connected to the input end of the constant current source circuit through the no-load protection circuit, and the output of the constant current source circuit connected to the output pin. The control circuit includes the output power control circuit at the output end of the electronic ballast, the filter circuit for IC chip rectification and the constant current control circuit of the IC chip. Through the present invention, the output power and constant current output can be freely adjusted by the user, suitable for The LED circuit brings convenience for the direct replacement of various existing electronic ballasts driving fluorescent lamps, metal halide lamps and sodium lamps.

Description

Electronic ballast directly drives LED IC chip and its control circuit

technical field

The invention relates to an IC chip and its control circuit, in particular to an IC chip and its control circuit for an electronic ballast directly driving an LED.

Background technique

LED has the advantages of low power consumption and long service life, and has been widely used in lighting, display and other fields, such as LED lighting, LED display screen, LED lighting and so on. With the country's increasing emphasis on green light sources, the market and application prospects of LED products are very broad. Since the LED is driven by DC voltage, the mains voltage cannot be directly used, and the LED drive power supply that converts the mains voltage into a DC voltage must be used. The current LED drive power supply is basically a constant current drive power supply in the form of a switching power supply, but it generally has the disadvantage of high cost. As we all know, AC electronic ballasts for fluorescent lamps have a development history of more than 20 years. They are already very mature in technology, and the cost is also very reasonable. Under the same power condition, the cost of electronic ballasts is only one-third of the cost of switching power supplies for LED drivers. One, so using electronic ballasts to drive LEDs has many advantages.

Chinese Patent Publication No.: 102647838A, published on August 22, 2012, discloses a conversion module for electronic ballasts to drive LEDs. The conversion module is connected between the electronic ballast and the LED array, and is characterized in that The conversion module includes a high-frequency current-limiting circuit for adjusting the high-frequency and high-voltage AC current at the output end of the electronic ballast, a rectification and filtering circuit for rectification and filtering to become a stable DC, and an initial voltage stabilization circuit for adjusting and adapting to the LED driving voltage. It is cooperatingly connected with the constant current drive circuit used for adjusting the current control required by the LED, the high frequency current limiting circuit, the rectification filter circuit, the initial voltage stabilization circuit and the constant current drive circuit. This technical solution uses electronic ballasts to drive LEDs, but there is a lot of power loss in this technical solution, especially the resistance elements, inductors and triodes, which will consume more power and generate more heat. It also has a greater impact on the service life of circuit components.

Contents of the invention

The purpose of the present invention is to solve the power loss of various lighting technologies driven by existing electronic ballasts, especially the resistance elements in which more power will be consumed and heat will be more , short life and air pollution problems, provide an electronic ballast with less consumption, less heat generation, simple components, easy integration, and long service life to directly drive the IC chip of the LED and its control circuit.

The technical scheme adopted by the present invention to solve the technical problem is: an electronic ballast directly drives an IC chip of an LED, including an input pin and an output pin, and also includes a rectifier circuit, a no-load protection circuit and a constant current source circuit, The input end of the rectification circuit is connected to the input pin, the output end of the rectification circuit is connected to the input end of the constant current source circuit through the no-load protection circuit, and the output end of the constant current source circuit is connected to the output pin. The invention is set in this way, by rectifying and outputting the output current of the electronic ballast, a stable constant current can be output to the LED circuit to drive the LED circuit for lighting. The invention consumes less, generates less heat, and has simple components , easy to integrate, bidirectional thyristor Q1 works in a semi-conducting state, plays the role of no-load protection, and has a long service life. The invention can freely adjust the output power and constant current by the user through the IC chip and peripheral circuits The output size is suitable for various LED circuits, and it can drive fluorescent lamps of different shapes for various existing electronic ballasts, such as: straight lamp tubes, ring lamp tubes, H-shaped lamp tubes, and metal halide lamps, high, Direct replacement of low-pressure sodium lamps brings convenience.

Preferably, the IC chip of the electronic ballast directly driving the LED further includes a protection circuit, the input terminal of the protection circuit is connected to the input pin, and the output terminal of the protection circuit is connected to the input terminal of the rectification circuit. The protection circuit protects the high-frequency and high-voltage circuit output by the electronic ballast, preventing the sudden distortion of high-frequency current from damaging some electronic components in the IC chip.

As a preference, the IC chip of the electronic ballast directly driving the LED is an eight-pin package chip, the rectifier circuit includes diode D1, diode D2, diode D3 and diode D4, and the no-load protection circuit includes diode D5, bidirectional thyristor Q1 and Resistor R3, the anode of diode D1 is connected to the cathode of diode D3, the anode of diode D3 is connected to the anode of diode D4, the cathode of diode D4 is connected to the anode of diode D2, the cathode of diode D2 is connected to the cathode of diode D1, the diode D5 The anode is connected to the cathode of the diode D2 and the cathode of the diode D1, the first anode of the bidirectional thyristor Q1 is connected to the cathode of the diode D2 and the cathode of the diode D1, and the second anode of the bidirectional thyristor Q1 is connected to the anode of the diode D3 and the anode of the diode D4 , the control electrode of the bidirectional thyristor Q1 is connected to the cathode of the diode D5 through the resistor R3, the anode of the diode D1 leads to the first and second pins, the cathode of the diode D4 leads to the third pin and the fourth pin, the bidirectional thyristor Q1 The second anode of the diode D5 leads to the fifth pin, the cathode of the diode D5 leads to the eighth pin, the cathode of the diode D5 is also connected to the constant current source circuit, and the constant current source circuit is connected to the sixth pin and the seventh pin. Diode D1, diode D2, diode D3 and diode D4 form a rectification circuit to rectify the current. Diode D5, resistor R3 and bidirectional thyristor Q1 form a no-load protection circuit. When the output terminal of the IC chip is no-load, the bidirectional thyristor Q1 works at half The conduction state plays the role of no-load protection, and the setting of diode D5 prevents directional current and ensures the direction of current.

Preferably, the constant current source circuit includes a transistor Q3, a field effect transistor Q2 and a resistor R4, the cathode of the diode D5 is connected to the collector of the transistor Q3 through the resistor R4, the emitter of the transistor Q3 is connected to the anode of the diode D3 and the diode D4 The anode of the transistor Q3 is connected to the substrate and source of the field effect transistor Q2, the gate of the field effect transistor Q2 is connected to the collector of the transistor Q3, and the drain of the field effect transistor Q2 is drawn as the seventh pin , the source of the field effect transistor Q2 is led out to the sixth pin, and the emitter of the triode Q3 is connected to the fifth pin. Use triode Q3 and field effect transistor Q2 to constitute constant current source among the present invention, wherein the present invention adopts field effect transistor Q2 instead of adopting triode, because, field effect transistor is a voltage control device, if adopt triode to replace field effect in the present invention Tube Q2 will have more loss and higher calorific value, which will affect the service life of the fast IC chip and the working consumption of the driven LED circuit.

Preferably, the protection circuit includes a resistor R1 and a resistor R2, one end of the resistor R1 is connected to the first pin, the other end of the resistor R1 is connected to the second pin, one end of the resistor R2 is connected to the third pin, and the resistor The other end of R2 is connected to the fourth pin. The protection circuit protects the high-frequency and high-voltage circuit output by the electronic ballast, preventing the instantaneous distortion of high-frequency current from damaging some electronic components in the IC chip. The design of the resistor R1 and the resistor R2 is simple and feasible, and can achieve the original intention of the design.

Preferably, the resistance value of the resistor R3 ranges from 200K ohms to 330K ohms, and the resistance value of the resistor R4 ranges from 1.5M ohms to 2M ohms. The resistance values of the resistors R3 and R4 are set in such a way that the gate voltage of the bidirectional thyristor Q1 and the voltage loaded on the resistors R4 and R3 can ensure the voltage value at the input terminal of the constant current source.

A control circuit for electronic ballasts to directly drive LEDs, used to drive LED circuits, including IC chips for direct driving LEDs by any electronic ballast as described in claims 3 to 6 and electronic ballasts with two inputs and four outputs The electronic ballast directly drives the LED control circuit also includes an inductor L, a resistor RT and a capacitor C, and the first output terminal of the electronic ballast is connected with the first pin of the IC chip that the electronic ballast directly drives the LED. Electrically connected, the second output terminal of the electronic ballast is electrically connected to the second pin of the IC chip that the electronic ballast directly drives the LED, and the third output terminal of the electronic ballast is connected to the IC chip that the electronic ballast directly drives the LED The third pin is electrically connected, the fourth output terminal of the electronic ballast is electrically connected to the fourth pin of the IC chip that the electronic ballast directly drives the LED, and the first end of the resistor RT is connected to the IC that the electronic ballast directly drives the LED The sixth pin of the chip is electrically connected, the second end of the resistor RT is electrically connected to the fifth pin of the IC chip that the electronic ballast directly drives the LED, and the anode of the capacitor C is connected to the eighth pin of the IC chip that the electronic ballast directly drives the LED. Pin electrical connection, the cathode of the capacitor C is electrically connected to the fifth pin of the IC chip that the electronic ballast directly drives the LED, one end of the inductor L is electrically connected to the second pin of the IC chip that the electronic ballast directly drives the LED, the inductor L The other end of the LED circuit is electrically connected to the third pin of the IC chip that the electronic ballast directly drives the LED, the first end of the LED circuit is electrically connected to the eighth pin of the IC chip that the electronic ballast directly drives the LED, and the second end of the LED circuit The terminal is electrically connected with the seventh pin of the IC chip that the electronic ballast directly drives the LED. The input of the existing dual-input four-output ballast is an AC input, the first output terminal and the fourth output terminal of the four output terminals are connected to the ballast inductor, and the second output terminal and the third output terminal are connected to the power compensation capacitor connection, the IC chip in the present invention plays rectification, no-load protection and constant current effect, and the peripheral control circuit includes the output power control circuit of the output terminal of the electronic ballast, the filter circuit after the rectification of the IC chip and the constant current source of the IC chip There are three kinds of circuits for constant current control circuit. The inductance L is used as the output power control circuit at the output end of the electronic ballast to adjust the output current frequency, and the frequency of the original electronic ballast output current is changed through the inductance L, so as to adjust the electronic ballast. The role of the output power of the output terminal of the device, the resistance RT as the constant current source of the IC chip constant current control circuit plays the role of adjusting the output constant current, the capacitor C is used as the filter circuit after the rectification of the IC chip for filtering, through the above components The mutual cooperation achieves the function of stably driving the LED circuit.

Preferably, the inductance L is a variable inductance, and the resistor RT is a variable resistor. With this setting, the user can adjust the output current by adjusting the inductor L and the resistor RT, which is suitable for various LED circuits.

The substantive effects of the present invention are: the present invention consumes less, generates less heat, has simple components and is easy to integrate, and the bidirectional thyristor Q1 works in a semi-conducting state, plays the role of no-load protection, and has a long service life. The invention can be adjusted freely by users and can be suitable for various LED circuits.

Description of drawings

Fig. 1 is the block diagram of the circuit structure of IC chip among the present invention;

Fig. 2 is a block diagram of the circuit structure of the present invention.

In the figure: 1. Protection circuit, 2. Rectification circuit, 3. No-load protection circuit, 4. Constant current source circuit, 5. IC chip.

detailed description

The technical solutions of the present invention will be further specifically described below through specific embodiments and in conjunction with the accompanying drawings.

Example 1:

An electronic ballast directly drives an IC chip for LEDs (see Figure 1), which is an eight-pin package chip, including four input pins and four output pins, and also includes a protection circuit 1, a rectification circuit 2, and no-load protection For the circuit 3 and the constant current source circuit 4, the input end of the protection circuit is connected to the input pin, and the output end of the protection circuit is connected to the input end of the rectification circuit. The input end of the rectification circuit 2 is connected to the input pin through the protection circuit 1, the output end of the rectification circuit 2 is connected to the input end of the constant current source circuit 4 through the no-load protection circuit 3, and the output end of the constant current source circuit 4 is connected to the output pin connection.

The protection circuit 1 includes a resistor R1 and a resistor R2. One end of the resistor R1 is connected to the first pin, the other end of the resistor R1 is connected to the second pin, one end of the resistor R2 is connected to the third pin, and the other end of the resistor R2 is connected to the third pin. The fourth pin is connected.

The rectifier circuit 2 includes a diode D1, a diode D2, a diode D3, and a diode D4. The no-load protection circuit includes a diode D5, a bidirectional thyristor Q1, and a resistor R3. The anode of the diode D1 is connected to the cathode of the diode D3, and the anode of the diode D3 is connected to the diode D4. The anode is connected, the cathode of the diode D4 is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the cathode of the diode D1, the anode of the diode D5 is connected to the cathode of the diode D2 and the cathode of the diode D1, and the first anode of the bidirectional thyristor Q1 is connected to the diode The cathode of D2 is connected to the cathode of diode D1, the second anode of bidirectional thyristor Q1 is connected to the anode of diode D3 and the anode of diode D4, the control electrode of bidirectional thyristor Q1 is connected to the cathode of diode D5 through resistor R3, and the anode of diode D1 leads out are the first and second pins, the cathode of the diode D4 leads to the third pin and the fourth pin, the second anode of the bidirectional thyristor Q1 leads to the fifth pin, and the cathode of the diode D5 leads to the eighth pin, The cathode of the diode D5 is also connected to the constant current source circuit, and the constant current source circuit is connected to the sixth pin and the seventh pin.

The constant current source circuit 4 includes a transistor Q3, a field effect transistor Q2 and a resistor R4, the cathode of the diode D5 is connected to the collector of the transistor Q3 through the resistor R4, the emitter of the transistor Q3 is connected to the anode of the diode D3 and the anode of the diode D4 connection, the base of the transistor Q3 is connected to the substrate and the source of the field effect transistor Q2, the gate of the field effect transistor Q2 is connected to the collector of the transistor Q3, and the drain of the field effect transistor Q2 is drawn as the seventh pin, the field The source of the effect transistor Q2 is led out to the sixth pin, and the emitter of the triode Q3 is connected to the fifth pin.

In this embodiment, the resistance value of the resistor R3 is 200K ohms, and the resistance value of the resistor R4 is 1.5M ohms.

The electronic ballast disclosed in this embodiment directly drives the IC chip of the LED. The application of this IC chip can perform distortion protection, rectification, voltage regulation, and power adjustment on high-frequency and high-voltage circuits to achieve constant current output. This embodiment is small and exquisite, especially Applicable and integrated in LED lamp circuit. The protection circuit of this embodiment protects the high-frequency and high-voltage circuit output by the electronic ballast, preventing the distortion of high-frequency current output from damaging some electronic components in the IC chip. The design of the resistor R1 and the resistor R2 is simple and feasible, and can achieve the original intention of the design. Diode D1, diode D2, diode D3 and diode D4 form a rectification circuit to rectify the current. In the present invention, triode Q3 and field effect transistor Q2 are used to form a constant current source, and the present embodiment uses field effect transistor Q2 instead of triode , because the field effect tube is a voltage control device, if a triode is used instead of the field effect tube Q2 in the present invention, there will be more loss and higher calorific value, which will affect the service life of the really fast IC chip and the driven LED circuit time work consumption. By rectifying and constant-current outputting the output current of the electronic ballast, a stable constant-current current can be output to the LED circuit to drive the LED circuit for lighting. Diode D5, resistor R3 and bidirectional thyristor Q1 form a no-load protection circuit. When the output terminal of the IC chip is no-load, the bidirectional thyristor Q1 works in a semi-conducting state, which plays the role of no-load protection. The setting of diode D5 prevents the directional current , to ensure the current direction.

A control circuit for an electronic ballast to directly drive an LED (see Figure 2), used to drive an LED circuit, including an IC chip 5 for an electronic ballast to directly drive an LED as described in Embodiment 1 and dual-input and four-output The electronic ballast, the control circuit of the electronic ballast directly driving the LED also includes an inductor L, a resistor RT and a capacitor C, the first output terminal of the electronic ballast and the IC chip of the electronic ballast directly driving the LED 5. The first pin is electrically connected, that is, the resistor R1 in the IC chip 5 is connected to the anode of the diode D1; the second output terminal of the electronic ballast is connected to the second pin of the IC chip 5 that the electronic ballast directly drives the LED. connected, that is, directly connected to the anode of the diode D1 in the IC chip 5; the third output terminal of the electronic ballast is electrically connected to the third pin of the IC chip 5 that the electronic ballast directly drives the LED, that is, directly connected to the IC chip 5 The cathode of the diode D4 in the circuit is connected; the fourth output terminal of the electronic ballast is electrically connected with the fourth pin of the IC chip 5 that the electronic ballast directly drives the LED, that is, through the resistor R2 in the IC chip 5 and the cathode of the diode D4 connection; the first end of the resistor RT is electrically connected to the sixth pin of the IC chip 5 directly driving the LED by the electronic ballast, that is, connected to the base of the triode Q3 in the IC chip 5; the second end of the resistor RT is connected to the electronic ballast The fifth pin of the IC chip 5 that directly drives the LED is electrically connected to the emitter of the triode Q3 in the IC chip 5; the anode of the capacitor C is electrically connected to the eighth pin of the IC chip 5 that the electronic ballast directly drives the LED. , that is, be connected with the cathode of diode D5 in IC chip 5; the cathode of capacitor C is electrically connected with the fifth pin of IC chip 5 that electronic ballast directly drives LED, that is, be connected with the emitter of triode Q3 in IC chip 5; One end of L is electrically connected to the second pin of the IC chip 5 that the electronic ballast directly drives the LED, that is, it is connected to the anode of the diode D1 in the IC chip 5; the other end of the inductor L is connected to the IC chip that the electronic ballast directly drives the LED 5 The third pin is electrically connected, that is, it is connected with the anode of the diode D2 in the IC chip 5; The cathode of the diode D5 in the middle is connected; the second end of the LED circuit is electrically connected with the seventh pin of the IC chip that the electronic ballast directly drives the LED, that is, connected with the drain of the field effect transistor Q2 in the IC chip 5 .

The input of the existing dual-input four-output ballast is an AC input, the first output terminal and the fourth output terminal of the four output terminals are connected to the ballast inductor, and the second output terminal and the third output terminal are connected to the power compensation capacitor connection, the IC chip in this embodiment plays the role of rectification, no-load protection and constant current, and the peripheral control circuit includes the output power control circuit at the output end of the electronic ballast, the filter circuit after the rectification of the IC chip and the constant current source of the IC chip The constant current size control circuit has three circuits, the inductance L is used as the output power control circuit of the output terminal of the electronic ballast to adjust the output current frequency, and the frequency of the original electronic ballast output output current is changed through the inductance L, so as to achieve the adjustment of the electronic ballast. The role of the output power at the output end of the ballast, the resistor RT as the constant current source of the IC chip, the constant current control circuit plays the role of adjusting the output constant current, and the capacitor C is used as the filter circuit after the rectification of the IC chip for filtering. The mutual cooperation of the above components achieves the function of stably driving the LED circuit.

Example 2:

This embodiment is basically the same as Embodiment 1, except that the resistor R3 in this embodiment has a resistance value of 330K ohms, and the resistor R4 has a resistance value of 2M ohms. The inductor L in this embodiment is a variable inductor, and the resistor RT is a variable resistor.

In this embodiment, the user can adjust the output current by adjusting the inductance L and the resistance RT, so that various LED circuits can output matching driving currents.

This embodiment can solve the problems of large power loss, short life and air pollution of various lighting technologies driven by existing electronic ballasts. This embodiment consumes less, generates less heat, has simple components, is easy to integrate, and is bidirectional Thyristor Q1 works in a semi-conducting state, plays the role of no-load protection, and has a long service life. In this embodiment, the user can freely adjust the output power and constant current output through the IC chip and peripheral circuits. It is suitable for various LED circuits and drives fluorescent lamps of different shapes for various existing electronic ballasts, such as: straight lamp tubes, ring lamp tubes, H-shaped lamp tubes, direct replacement of metal halide lamps, high and low pressure sodium lamps Bring convenience.

The embodiment described above is only a preferred solution of the present invention, and does not limit the present invention in any form. There are other variations and modifications on the premise of not exceeding the technical solution described in the claims.

Claims (5)

1. An electronic ballast directly drives an IC chip of an LED, comprising input pins and output pins, characterized in that: it also includes a rectifier circuit, a no-load protection circuit and a constant current source circuit, the input terminal of the rectifier circuit and the input pin Pin connection, the output end of the rectifier circuit is connected to the input end of the constant current source circuit through the no-load protection circuit, and the output end of the constant current source circuit is connected to the output pin; the electronic ballast directly drives the LED The IC chip also includes a protection circuit, the input end of the protection circuit is connected to the input pin, and the output end of the protection circuit is connected to the input end of the rectification circuit; the IC chip of the electronic ballast directly driving the LED is eight-pin Package the chip, the rectifier circuit includes diode D1, diode D2, diode D3 and diode D4, the no-load protection circuit includes diode D5, bidirectional thyristor Q1 and resistor R3, the anode of diode D1 is connected to the cathode of diode D3, the anode of diode D3 is connected to the diode The anode of D4 is connected, the cathode of diode D4 is connected to the anode of diode D2, the cathode of diode D2 is connected to the cathode of diode D1, the anode of diode D5 is connected to the cathode of diode D2 and the cathode of diode D1, the first anode of bidirectional thyristor Q1 It is connected to the cathode of diode D2 and the cathode of diode D1, the second anode of bidirectional thyristor Q1 is connected to the anode of diode D3 and the anode of diode D4, the control electrode of bidirectional thyristor Q1 is connected to the cathode of diode D5 through resistor R3, and the second anode of diode D1 The anode is drawn out as the first and second pins, the cathode of the diode D4 is drawn out as the third pin and the fourth pin, the second anode of the bidirectional thyristor Q1 is drawn out as the fifth pin, and the cathode of the diode D5 is drawn out as the eighth pin pin, the cathode of diode D5 is also connected with the constant current source circuit, and the constant current source circuit is connected with the sixth pin and the seventh pin; the constant current source circuit includes triode Q3, field effect transistor Q2 and resistor R4, diode The cathode of D5 is connected to the collector of transistor Q3 through resistor R4, the emitter of transistor Q3 is connected to the anode of diode D3 and the anode of diode D4, the base of transistor Q3 is connected to the substrate and source of field effect transistor Q2, and the field The gate of the effect transistor Q2 is connected to the collector of the transistor Q3, the drain of the field effect transistor Q2 is connected to the seventh pin, the source of the field effect transistor Q2 is connected to the sixth pin, and the emitter of the transistor Q3 is connected to the fifth pin. pin connection. 2. The electronic ballast according to claim 1 directly drives the LED IC chip, characterized in that: the protection circuit includes a resistor R1 and a resistor R2, one end of the resistor R1 is connected to the first pin, and one end of the resistor R1 is connected to the first pin. The other end is connected to the second pin, one end of the resistor R2 is connected to the third pin, and the other end of the resistor R2 is connected to the fourth pin. 3. The electronic ballast according to claim 1 or 2, which directly drives the LED IC chip, is characterized in that: the resistance value of the resistor R3 ranges from 200K ohms to 330K ohms, and the resistance of the resistor R4 is Values range from 1.5M ohms to 2M ohms. 4. A control circuit for an electronic ballast to directly drive an LED, for driving an LED circuit, comprising any electronic ballast as claimed in claims 1 to 2 that directly drives an LED IC chip and a dual-input four-output The electronic ballast is characterized in that: the control circuit of the electronic ballast directly driving the LED also includes an inductor L, a resistor RT and a capacitor C, and the first output terminal of the electronic ballast directly drives the LED The first pin of the IC chip is electrically connected, the second output terminal of the electronic ballast is electrically connected to the second pin of the IC chip that the electronic ballast directly drives the LED, and the third output terminal of the electronic ballast is connected to the electronic ballast The third pin of the IC chip that directly drives the LED is electrically connected, the fourth output terminal of the electronic ballast is electrically connected to the fourth pin of the IC chip that the electronic ballast directly drives the LED, and the first end of the resistor RT is connected to the electronic ballast. The sixth pin of the IC chip directly driven by the ballast is electrically connected to the sixth pin of the IC chip, the second end of the resistor RT is electrically connected to the fifth pin of the IC chip directly driven by the electronic ballast, and the anode of the capacitor C is directly driven by the electronic ballast The eighth pin of the IC chip of the LED is electrically connected, the cathode of the capacitor C is electrically connected to the fifth pin of the IC chip directly driven by the electronic ballast, and one end of the inductor L is connected to the second pin of the IC chip directly driven by the electronic ballast The other end of the inductor L is electrically connected to the third pin of the IC chip that the electronic ballast directly drives the LED, and the first end of the LED circuit is electrically connected to the eighth pin of the IC chip that the electronic ballast directly drives the LED. The second end of the LED circuit is electrically connected to the seventh pin of the IC chip that the electronic ballast directly drives the LED. 5. The control circuit for electronic ballast directly driving LED according to claim 4, characterized in that: said inductance L is a variable inductance, and said resistor RT is a variable resistor.