CN112469157A - Xenon lamp-to-LED adapting circuit, LED adapting module and LED module - Google Patents

Abstract

The application discloses xenon lamp changes LED adapter circuit, LED adapter module and LED module relates to automotive electronics field, this application is through the voltage of sampling unit sampling rectification filtering unit output, utilize the hot start analog unit to produce the PWM ripples that duty cycle and sampling voltage positive correlation based on the voltage of sampling point and come the control reposition of redundant personnel unit, thereby share LED's power, can simulate the characteristics that HID high power starts like this, make at the start-up stage, LED can set for work under the electric current scope, and can not receive the destruction of too high power. The pulse width modulation unit is used for carrying out window comparison on signals respectively output by the negative resistance operation unit, the peak current limiting unit and the triangular wave generation unit to control the power driving unit, so that the current flowing through the constant current unit is constant.

Description

Xenon lamp-to-LED adapting circuit, LED adapting module and LED module

Technical Field

The application relates to the field of automotive electronics, in particular to a xenon lamp-to-LED adapting circuit, an LED adapting module and an LED module.

Background

Since the invention of the last 90 th century, the HID xenon lamp for vehicles has the characteristics of high brightness, long service life, complex circuit, high cost and the like, and is always the first choice of high-end automobile headlamps, and after the 20 th century, because of the maturity of the LED technology and the continuous reduction of the cost, the high-end vehicles begin to replace the original HID headlamps with the LEDs, and the replacement of the HID headlamps with the LEDs is a necessary trend.

Since the beginning of loading HID, over 1000 million vehicles are equipped with HID headlights every year, the quantity of the vehicles equipped with HID lamps in the whole world currently exceeds more than 3 hundred million, HID bulbs are consumables, the nominal service life is 2000 hours, early-stage D1 and D2 series HID bulbs contain harmful substances such as mercury, and later-stage D3, D4, D5 and D8 series HID bulbs adopt mercury-free technology, so that the product is more environment-friendly, but the problems of brightness reduction, service life shortening and the like are brought. Basically, there is a need to replace the light bulb when the vehicle is used for more than 3 years. The existing LED headlamp technology has great advantages over the original HID in terms of brightness, service life and cost, so that the LED lamp is a scheme which is beneficial to environmental protection, can improve product performance indexes and greatly reduce use cost, is beneficial to multiple aspects, and has wide market and good environmental benefit and economic benefit.

The HID bulb needs high-voltage starting, the waiting time for reaching rated brightness is long, and the like, so that the output characteristic of the HID electronic ballast is determined: the starting method comprises the steps of a, starting at high voltage of 23kv, b, starting power of about 2.5 times for cold starting in order to quickly reach rated brightness, starting completion time of about 60 seconds, c, hot starting power of about 1.3 times, starting completion time of about 10 seconds, d, alternating current square wave output, frequency of 200-400 hz, and e, wherein in order to ensure constant power, the HID bulb has negative resistance characteristic.

However, the LED emits light in a solid state, and has a light characteristic of being lighted and instantly reaching a rated brightness, and an electrical characteristic of requiring a constant current. Therefore, the working modes of the power supply circuit of the LED and the power supply circuit of the HID bulb are completely different, if a vehicle adopting the HID bulb needs to be provided with an LED lamp, the power supply circuit needs to be replaced, and the cost is high.

Disclosure of Invention

In view of this, the present application aims to: the xenon lamp-to-LED adapting circuit and the adapting module are provided to adapt to power circuits of an LED vehicle lamp and an HID bulb, and the replacement cost is reduced.

In a first aspect, an embodiment of the present application provides:

a xenon lamp-to-LED adaptation circuit, comprising:

the rectifying and filtering unit is used for converting alternating current into direct current and comprises a positive output end and a negative output end;

the sampling unit comprises a first resistor and a second resistor which are connected in series between the positive output end and the negative output end of the rectifying and filtering unit, and the connection point of the first resistor and the second resistor is used as a sampling point;

the input end of the hot start simulation unit is connected with the sampling point, and the output end of the hot start simulation unit outputs a PWM (pulse-width modulation) wave, wherein the duty ratio of the PWM wave is positively correlated with the voltage of the sampling point;

the shunt unit comprises a first power tube and a third resistor which are connected in series with the anode output end and the cathode output end, and the output end of the hot start simulation unit is connected with the control end of the first power tube;

the input end of the negative resistance operation unit is connected with the sampling point, and the negative resistance operation unit is used for amplifying the voltage of the sampling point in proportion and outputting a first voltage;

a triangular wave generating unit for generating a triangular wave;

the constant current unit comprises a power inductor, an LED interface, a second power tube and a current sampling resistor which are connected in series between the anode output end and the cathode output end, and also comprises a fly-wheel diode connected between the LED interface and the anode output end;

the peak current limiting unit is used for amplifying the voltage between the current sampling resistor and the negative electrode output end in proportion and outputting a second voltage;

the pulse width modulation unit comprises a first input end, a second input end and a third input end, the first input end of the pulse width modulation unit is connected with the output end of the negative resistance operation unit, the second input end of the pulse width modulation unit is connected with the output end of the triangular wave generation unit, and the third input end of the pulse width modulation unit is connected with the output end of the peak current limiting unit; the pulse width modulation unit outputs a first level when the voltage of the triangular wave is between a first voltage and a second voltage, and the pulse width modulation unit outputs a second level when the voltage of the triangular wave is smaller than the first voltage or larger than the second voltage;

and the power driving unit is connected with the output end of the pulse width modulation unit and is used for driving the second power tube based on a signal output by the output end of the pulse width modulation unit.

In some embodiments, the circuit further comprises an input voltage detection unit, and the negative resistance operation unit and the hot start simulation unit are respectively connected with the sampling point through the input voltage detection unit;

the input end of the input voltage detection unit is connected with the sampling point and used for following the voltage of the sampling point, the input voltage detection unit comprises a first output end and a second output end, the output voltage of the first output end is positively correlated with the voltage of the sampling point, and the output voltage of the second output end is positively correlated with the voltage of the sampling point.

In some embodiments, the hot start simulation unit, the shunt unit, the negative resistance operation unit, the triangular wave generation unit, the peak current limitation unit, the pulse width modulation unit, and the power driving unit are all integrated in one package.

In some embodiments, the circuit further comprises an internal power supply integrated in the package, the internal power supply being configured to convert the voltage output by the rectifying and filtering unit into a voltage for use inside the package.

In some embodiments, a fourth resistor is disposed between the internal power supply and the positive output terminal, and one end of the fourth resistor connected to the internal power supply is grounded through a first capacitor.

In some embodiments, the rectifying and filtering unit includes a rectifying bridge and a second capacitor, the second capacitor is connected between two output ends of the rectifying bridge, and two ends of the second capacitor respectively form the positive output end and the negative output end of the rectifying and filtering unit.

In some embodiments, the circuit further includes a thermistor, and an overheat protection unit disposed in the package, the overheat protection unit being connected to an enable terminal of the pulse width modulation unit.

In some embodiments, the pulse width modulation unit is a window comparator.

In a second aspect, embodiments of the present application provide:

the LED adaptation module comprises a circuit board, wherein the circuit board is provided with the xenon lamp-to-LED adaptation circuit.

In a third aspect, embodiments of the present application provide:

an LED module comprising an LED and the adaptation module.

The embodiment of the application utilizes the hot start simulation unit through the voltage of sampling unit sampling rectification filter unit output, and the voltage based on the sampling point produces the PWM ripples that duty cycle and sampling voltage positive correlation and controls the reposition of redundant personnel unit to share LED's power, can simulate the characteristics that HID high power starts like this, make in the start-up stage, LED can set for work under the electric current scope, and can not receive the destruction of too high power. And then, the pulse width modulation unit performs window comparison on signals respectively output by the negative resistance operation unit, the peak current limiting unit and the triangular wave generation unit to control the power driving unit, so that the current flowing through the constant current unit (namely, the current flowing through the LED) is constant, therefore, the LED can be adapted to the HID ballast, a power circuit does not need to be replaced when the LED automobile lamp is replaced, and the replacement cost is lower.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic diagram of a circuit provided in accordance with an embodiment of the present application;

fig. 2 is a schematic diagram of an operating principle of a pulse width modulation unit according to an embodiment of the present application.

Detailed Description

In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below through embodiments with reference to the accompanying drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, a xenon lamp-to-LED adapting circuit includes:

the rectifying and filtering unit is used for converting alternating current into direct current and comprises a positive output end and a negative output end.

It is understood that the general rectifying and filtering unit includes a rectifying bridge and a filtering device, for example, in this embodiment, the rectifying bridge is formed by diodes D1-D4, and the filtering device is formed by a second capacitor C2. It is understood that VCC is a positive output terminal and VSS is a negative output terminal in the figure.

And the sampling unit comprises a first resistor R1 and a second resistor R2 which are connected between the positive output end and the negative output end of the rectifying and filtering unit in series, and the connection point of the first resistor R1 and the second resistor R2 serves as a sampling point.

The input end of the hot start simulation unit is connected with the sampling point, and the output end of the hot start simulation unit outputs a PWM wave, wherein the duty ratio of the PWM wave is in positive correlation with the voltage of the sampling point. That is, the hot start signal simulator is essentially a PWM generator, which can be implemented by a general triangular wave generator and a comparator, a positive phase input terminal of the comparator is a voltage of the sampling point (or a voltage positively correlated to the voltage of the sampling point), a negative phase input terminal of the comparator is an output signal of the triangular wave generator, when the voltage of the sampling point is higher than the voltage of the triangular wave, the hot start simulation unit outputs a high level, and conversely outputs a low level, and thus, a PWM signal whose duty ratio is positively correlated to the voltage of the sampling point can be output. When the output voltage of the HID ballast becomes low (the power is reduced after the warm start), the voltage of a sampling point is less than or equal to the minimum voltage of a triangular wave, and the warm start analog unit only outputs a low level, which is equivalent to the disconnection of the shunt unit.

And the shunt unit comprises a first power tube Q1 and a third resistor R3 which are connected in series with the positive output end and the negative output end, and the output end of the hot start analog unit is connected with the control end of the first power tube.

It can be understood that the shunt unit consumes power through the third resistor R3, and in view of the parallel connection relationship with the constant current unit, the shunt unit can conduct shunt by turning on the first power transistor Q1, so as to achieve power consumption. Therefore, the high-voltage starting characteristic of the HID ballast can be adapted, the working current of the LED is kept constant, and the LED is prevented from being damaged or the service life of the LED is prevented from being reduced. It should be understood that the device parameters can be adjusted to properly shunt current according to the model of the HID ballast to be adapted.

And the input end of the negative resistance operation unit is connected with the sampling point, and the negative resistance operation unit is used for carrying out proportional amplification on the voltage of the sampling point and outputting a first voltage V1. It will be appreciated that the negative resistance unit acts as a proportional amplifier, wherein it may equally follow up amplification of a ratio greater than 1, or amplification of a ratio less than 1 (i.e. signal attenuation) when scaling up.

And the triangular wave generating unit is used for generating a triangular wave. The triangular wave generating unit comprises a 100KHz oscillator and a triangular wave generator, wherein the triangular wave generator generates a triangular wave signal based on an oscillation signal of the oscillator. It will be appreciated that the unit may also provide triangular waves to the hot start simulation unit.

The constant current unit comprises a power inductor L1, an LED interface (used for connecting an LED), a second power tube Q2 and a current sampling resistor R5 which are connected in series between the anode output end and the cathode output end, and a freewheeling diode D5 connected between the LED interface and the anode output end.

And the peak current limiting unit is used for amplifying the voltage between the current sampling resistor R5 and the negative output terminal VSS in proportion and outputting a second voltage V2.

The pulse width modulation unit comprises a first input end, a second input end and a third input end, the first input end of the pulse width modulation unit is connected with the output end of the negative resistance operation unit, the second input end of the pulse width modulation unit is connected with the output end of the triangular wave generation unit, and the third input end of the pulse width modulation unit is connected with the output end of the peak current limiting unit. The pulse width modulation unit outputs a first level when the voltage of the triangular wave is between a first voltage and a second voltage, and the pulse width modulation unit outputs a second level when the voltage of the triangular wave is smaller than the first voltage or larger than the second voltage.

It is understood that, in the present embodiment, the pulse width modulation unit may be a window comparator, or a processor with a simple numerical comparison function, and outputs a PWM wave based on the above three signals. Referring to fig. 1 and 2, fig. 2 shows the relationship of input signals of the pulse width modulation unit. Wherein the first voltage V1 is less than the second voltage V2, and V0 represents the output signal of the pulse width modulation unit.

And the power driving unit is connected with the output end of the pulse width modulation unit and is used for driving the second power tube Q2 based on a signal output by the output end of the pulse width modulation unit. In general, the output signal of the power driving unit follows the signal output by the pulse width modulation unit, and the amplitude of the signal is adjusted to drive the subsequent circuit.

To sum up, this application embodiment utilizes hot start analog unit through the voltage of sampling unit sampling rectification filtering unit output, produces the PWM ripples that duty cycle and sampling voltage are positive correlation based on the voltage of sampling point and controls the reposition of redundant personnel unit to share LED's power, can simulate the characteristics that HID high power starts like this, make in the start-up stage, LED can set for work under the electric current scope, and can not receive the destruction of too high power. And then, the pulse width modulation unit performs window comparison on signals respectively output by the negative resistance operation unit, the peak current limiting unit and the triangular wave generation unit to control the power driving unit, so that the current flowing through the constant current unit (namely, the current flowing through the LED) is constant, therefore, the LED can be adapted to the HID ballast, a power circuit does not need to be replaced when the LED automobile lamp is replaced, and the replacement cost is lower.

In some embodiments, the circuit further includes an input voltage detection unit, and the negative resistance operation unit and the warm start simulation unit are respectively connected to the sampling points through the input voltage detection unit.

The input end of the input voltage detection unit is connected with the sampling point and used for following the voltage of the sampling point, the input voltage detection unit comprises a first output end and a second output end, the output voltage of the first output end is positively correlated with the voltage of the sampling point, and the output voltage of the second output end is positively correlated with the voltage of the sampling point.

It can be understood that, since the proportion of the voltages input by the negative resistance operation unit and the hot start analog unit to the sampling point may be different, the voltage adaptation can be realized by arranging one input voltage detection unit. For example, the voltage detection unit may be composed of two different proportional amplifiers. The amplification ratios of the output signals to the proportional amplifiers of the negative resistance operation unit and the hot start analog unit are different, and the circuits can be flexibly configured in such a way.

In some embodiments, the hot start simulation unit, the shunt unit, the negative resistance operation unit, the triangular wave generation unit, the peak current limitation unit, the pulse width modulation unit, and the power driving unit are all integrated in one package. In this embodiment, some units may be integrated into one package to form a chip or a module, which is convenient for downstream manufacturers to assemble.

In some embodiments, the circuit further comprises an internal power supply integrated in the package, the internal power supply being configured to convert the voltage output by the rectifying and filtering unit into a voltage for use inside the package. It is understood that in this embodiment, the units in the package may use different dc voltages, for example, the comparator typically uses 5V or 3.3V, while the power driving unit may use 12V or higher, so that a plurality of voltage stabilizing chips may be used to output different dc voltages. As shown in fig. 1, in the present embodiment, a reference voltage of 5V is set.

In some embodiments, a fourth resistor R4 is disposed between the internal power supply and the positive output terminal, and one end of the fourth resistor R4 connected to the internal power supply is grounded through a first capacitor. The fourth resistor R4 is a current limiting resistor to prevent voltage surges from damaging the cells in the package.

In some embodiments, the rectifying and filtering unit includes a rectifying bridge and a second capacitor C2, the second capacitor C2 is connected between two output ends of the rectifying bridge, and two ends of the second capacitor respectively constitute the positive output end VCC and the negative output end VSS of the rectifying and filtering unit.

In some embodiments, the circuit further comprises a thermistor R6, and an overheat protection unit disposed in the package, the overheat protection unit being connected to an enable terminal of the pulse width modulation unit. The thermistor R6 is used to sense the temperature inside the package.

It can be understood that the overheating protection unit determines whether overheating occurs by detecting a resistance change of the thermistor R6, wherein the overheating protection unit includes a resistor having one end connected to VCC and the other end connected to ground through R6, when the temperature rises, the resistance of the thermistor R6 changes, then the overheating protection unit compares the reference voltage with the voltage across the thermistor through the comparator, and can change the output level of the comparator when the temperature detected by the thermistor exceeds the threshold value, thereby turning off the output of the pulse width modulation unit and the circuit in the package.

In some embodiments, the pulse width modulation unit is a window comparator. It should be understood that the window comparator includes three input terminals, one of which is a signal input terminal and the other two of which are output terminals of the reference voltage, in this embodiment, the input signal is a triangular wave, and the window comparator outputs a high level when the voltage of the triangular wave is between the two reference voltages, and outputs a low level when the voltage of the triangular wave is outside the two reference voltages (i.e., less than the smaller reference voltage or greater than the larger reference voltage).

The following description is made in conjunction with specific HID models:

a starting stage: when the xenon lamp is started, alternating current voltage output by the HID ballast is rectified and filtered into direct current through a rectifier bridge and a second capacitor C2, the integrated circuit simultaneously carries out two paths of output actions, one path is driven by pulse width modulation and power, the LED lamp is lightened by a second power tube Q2(MOS tube), the other path simulates a first power tube Q1 by controlling hot start according to the change of input voltage and a hot start simulation unit, the first power tube Q1 and a third resistor R3 detect the input voltage, the hot start simulation unit jointly completes a hot start control loop for about 10 seconds, the circuit is gradually reduced to 35w of normal work by hot start power 45w, and the start ending circuit enters a constant power mode.

And (3) a normal working stage: after the starting is finished, the circuit enters a normal working mode, due to the characteristics of the xenon lamp, the working voltage of D1 with mercury and the working voltage of D2 series are AC85V, the working voltage of D3 without mercury, D4, D5 and D8 series are AC43V, in order to have higher adaptability, the working voltage range in the packaging of the scheme is designed to be 8V-100V, and power is supplied through a fourth resistor R4.

The oscillator, the triangular wave generator, the pulse width modulation unit, the power driving unit, the second power tube Q2, the current sampling resistor R5 and the error amplifier form an LED constant current loop, the resistance value of the current sampling resistor R5 is changed, and the current of the LED can be adjusted. The peak current limiting circuit can limit the maximum peak value of a single pulse, reduce output impact on the HID ballast and better simulate the circuit into a resistive load.

A negative resistance operation unit: the xenon bulb has a negative resistance characteristic, so that the voltage at two ends of the voltage is reduced when the current flowing through the bulb is increased, the whole LED headlamp loop is simulated to have the negative resistance characteristic by the integrated circuit, and when the output current is increased, the output voltage must be reduced from the output end of the LED ballast, so that the constant power output by the HID ballast is ensured. Therefore, the negative resistance operation unit is used for adjusting the pulse width modulation unit according to the change of the input voltage, reducing the input current when the input voltage is increased, increasing the input current when the input voltage is reduced, enabling the whole current to present the negative resistance characteristic, and ensuring the constant power output by the hid ballast.

The working principle of the hot start simulation unit is as follows: when the HID ballast is just started, whether the bulb is in a cold start state or a hot start state is judged according to the voltage and the current at two ends of the bulb, when the control circuit is just electrified, the hot start analog unit outputs a high level, the first power tube Q1 is conducted, the third resistor R3 is merged into a load loop, the power of the third resistor R3 is about 10w, the power of an LED load loop is about 35w, the total power is about 45w, the circuit voltage value is set to be 95v/D1, D2, 55v/D3 and D4, therefore, the HID ballast outputs a power curve according to the characteristic of hot start, the output voltage of the HID ballast is gradually reduced, the 35w power of the LED is kept unchanged, the output of the hot start analog unit is converted from the high level to PWM, the power of the third resistor R3 is also gradually reduced, and when the output voltage of the ballast is reduced to about 85v, the hot start analog unit outputs a low level, the first power tube Q1 is turned off, the warm start is finished, only the LED output part works, and the power of the whole circuit is 35 w.

The working principle of the negative resistance operation unit is as follows: when the input voltage becomes low, the input voltage detection unit controls the PWM circuit, the output duty ratio of the PWM is improved, the input current is increased, the constant power characteristic of the circuit is ensured, the lower the voltage is, the larger the current I is, the current I is equal to U/R, and the lower the equivalent resistance R is, so the equivalent resistance of the circuit is in the negative resistance characteristic, namely the larger the current is, the smaller the resistance is, the circuit takes the input voltage as a feedback parameter, the constant power characteristic of the whole circuit is ensured, and the equivalent resistance of the whole circuit is in the negative resistance characteristic.

The working principle of the peak current limiting unit is as follows: in a pulse conduction period, the start point of pulse conduction is controlled by the negative resistance operation unit, the second power tube Q2 is conducted through power driving output, the current is linearly increased due to the power inductor L1, the voltage on the current sampling resistor R5 is also linearly increased in slope, when the current is increased to a preset value, the pulse is closed, and the maximum current peak value can be adjusted by adjusting the current sampling resistor R5.

Control logic of the pulse width modulation unit: the oscillation circuit and the triangular wave generator generate a triangular wave of 100kHz, the pulse width modulation unit compares the triangular wave with a first voltage V1 output by the negative resistance operation unit and a voltage V2 output by the peak current limiting unit, when the triangular wave voltage rises to be higher than the first voltage V1 output by the negative resistance operation unit, the PWM outputs a high level, the power driving circuit drives the second power tube Q2 to be switched on, when the triangular wave voltage continues to rise to a peak current control output voltage V2, the PWM outputs a low level, the power driving circuit drives the second power tube Q2 to be switched off, a pulse width modulation period is completed, the negative resistance operation unit output voltage V1 determines a pulse starting time, and the peak current control voltage V2 determines a pulse switching-off time.

A temperature control circuit: by utilizing the temperature characteristic of the semiconductor inside the package, when the temperature inside the package reaches a set value, the output of the PWM is turned off, the whole circuit is protected from being damaged due to overheating, and the temperature starting point can be adjusted by the thermistor R6.

The embodiment discloses an LED adaptation module, which comprises a circuit board, wherein the circuit board is provided with a xenon lamp-to-LED adaptation circuit.

It will be appreciated that the present application protects a module for mounting components on a circuit board, which module may be enclosed in a housing.

The embodiment discloses an LED module, which comprises an LED and the adapting module. The LED referred to in this embodiment is generally a vehicle light, such as a headlamp.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present application and the technical principles employed. It will be understood by those skilled in the art that the present application is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the application. Therefore, although the present application has been described in more detail with reference to the above embodiments, the present application is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims (10)

1. A xenon lamp-to-LED adaptation circuit, comprising:

the rectifying and filtering unit is used for converting alternating current into direct current and comprises a positive output end and a negative output end;

the sampling unit comprises a first resistor and a second resistor which are connected in series between the positive output end and the negative output end of the rectifying and filtering unit, and the connection point of the first resistor and the second resistor is used as a sampling point;

the input end of the hot start simulation unit is connected with the sampling point, and the output end of the hot start simulation unit outputs a PWM (pulse-width modulation) wave, wherein the duty ratio of the PWM wave is positively correlated with the voltage of the sampling point;

the shunt unit comprises a first power tube and a third resistor which are connected in series with the anode output end and the cathode output end, and the output end of the hot start simulation unit is connected with the control end of the first power tube;

the input end of the negative resistance operation unit is connected with the sampling point, and the negative resistance operation unit is used for amplifying the voltage of the sampling point in proportion and outputting a first voltage;

a triangular wave generating unit for generating a triangular wave;

the constant current unit comprises a power inductor, an LED interface, a second power tube and a current sampling resistor which are connected in series between the anode output end and the cathode output end, and also comprises a fly-wheel diode connected between the LED interface and the anode output end;

the peak current limiting unit is used for amplifying the voltage between the current sampling resistor and the negative electrode output end in proportion and outputting a second voltage;

the pulse width modulation unit comprises a first input end, a second input end and a third input end, the first input end of the pulse width modulation unit is connected with the output end of the negative resistance operation unit, the second input end of the pulse width modulation unit is connected with the output end of the triangular wave generation unit, and the third input end of the pulse width modulation unit is connected with the output end of the peak current limiting unit; the pulse width modulation unit outputs a first level when the voltage of the triangular wave is between a first voltage and a second voltage, and the pulse width modulation unit outputs a second level when the voltage of the triangular wave is smaller than the first voltage or larger than the second voltage;

and the power driving unit is connected with the output end of the pulse width modulation unit and is used for driving the second power tube based on a signal output by the output end of the pulse width modulation unit.

2. The xenon lamp-to-LED adapting circuit according to claim 1, further comprising an input voltage detection unit, wherein the negative resistance operation unit and the hot start simulation unit are respectively connected with the sampling point through the input voltage detection unit;

the input end of the input voltage detection unit is connected with the sampling point and used for following the voltage of the sampling point, the input voltage detection unit comprises a first output end and a second output end, the output voltage of the first output end is positively correlated with the voltage of the sampling point, and the output voltage of the second output end is positively correlated with the voltage of the sampling point.

3. The xenon lamp-to-LED adapting circuit according to claim 1, wherein the hot start analog unit, the shunt unit, the negative resistance operation unit, the triangular wave generation unit, the peak current limiting unit, the pulse width modulation unit and the power driving unit are all integrated in one package.

4. The xenon-to-LED adapter circuit according to claim 3, further comprising an internal power supply integrated within the package, the internal power supply for converting the voltage output by the rectifying-filtering unit to a used voltage inside the package.

5. The xenon lamp-to-LED adapting circuit according to claim 4, wherein a fourth resistor is arranged between the internal power supply and the positive output end, and one end of the fourth resistor connected with the internal power supply is grounded through a first capacitor.

6. The xenon lamp-to-LED adapting circuit according to claim 1, wherein the rectifying and filtering unit comprises a rectifying bridge and a second capacitor, the second capacitor is connected between two output ends of the rectifying bridge, and two ends of the second capacitor respectively form the positive output end and the negative output end of the rectifying and filtering unit.

7. The xenon lamp-to-LED adapting circuit according to claim 3, further comprising a thermistor and an over-temperature protection unit disposed in the package, the over-temperature protection unit being connected to an enable terminal of the pulse width modulation unit.

8. The xenon-to-LED adapting circuit according to claim 1, wherein the pulse width modulation unit is a window comparator.

9. An LED adaptation module, characterized by comprising a circuit board, wherein the circuit board is provided with a xenon lamp-to-LED adaptation circuit according to any one of claims 1 to 8.

10. An LED module comprising an LED and the adaptation module of claim 9.

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