CN211509375U

CN211509375U - Drive circuit for driving LED device and LED circuit

Info

Publication number: CN211509375U
Application number: CN201922377379.9U
Authority: CN
Inventors: 刘肖峰; 刘路
Original assignee: Phoenix Contact Asia Pacific Nanjing Co Ltd
Current assignee: Phoenix Contact Asia Pacific Nanjing Co Ltd
Priority date: 2019-12-26
Filing date: 2019-12-26
Publication date: 2020-09-15
Anticipated expiration: 2029-12-26

Abstract

The utility model provides a drive circuit and LED circuit for driving LED device, drive circuit includes the input unit, the rectification filter unit, PWM control constant current unit and output voltage current adjustment unit, the input unit is used for receiving external power signal, the rectification filter unit is used for rectifying and filtering external power signal, PWM control constant current unit is used for carrying out steady voltage to the LED device, the stationary flow, output voltage current adjustment unit includes fifth resistance and zener diode, the LED device establishes ties with zener diode after connecting in parallel with the fifth resistance, and zener diode's positive terminal connects the positive terminal of LED device. The utility model discloses a drive circuit has realized super wide handing over, direct current input voltage scope around the design of LED constant current driver chip, has solved the problem that the service voltage scope is narrow, compatibility can be poor.

Description

Drive circuit for driving LED device and LED circuit

Technical Field

The utility model relates to an industrial control circuit technical field, concretely relates to a drive circuit and LED circuit for driving LED device.

Background

With the development of lighting technology, LED indicator lamps are more and more widely used. The traditional LED indicator lamp is divided into types and kinds according to different input voltages in a power grid, and is compatible with two power supply systems of alternating current and direct current through the design of a capacitor voltage reduction circuit, a rectifying circuit and an LED indicator lamp circuit. However, the design scheme has obvious problems, such as narrow voltage range of product use, poor compatibility, and multiple types of design schemes, which further leads to the increase of production management cost of enterprises. In addition, the traditional resistance voltage reduction circuit can cause the product to generate heat, and the long-term use can cause the aging of the device and influence the service life of the product.

Therefore, it is necessary to design a new driving circuit for driving an LED device and an LED circuit to solve the above problems.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a drive circuit and LED circuit for driving LED device, around the design of LED constant current drive chip, realized super wide handing over, direct current input voltage scope, solved the problem that the service voltage scope is narrow, compatibility can be poor.

To achieve the above object, the present invention provides a driving circuit for driving an LED device, which is characterized in that the driving circuit comprises: the input unit is used for receiving an external power supply signal and comprises a first input end and a second input end; the rectification filtering unit is connected between the first input end and the second input end and is used for rectifying and filtering the external power supply signal; the PWM control constant current unit comprises a constant current control chip, is connected between the positive electrode and the negative electrode of the output end of the rectification filter unit and is connected with the LED device in series, and is used for stabilizing the voltage and the current of the LED device; and the output voltage and current adjusting unit is connected between the PWM control constant current unit and the LED device and comprises a ninth control node, a tenth control node, a fifth resistor and a voltage stabilizing diode, wherein the ninth control node is coupled with the positive terminal of the LED device, the positive terminal of the voltage stabilizing diode and one end of the fifth resistor, the tenth control node is coupled with the negative terminal of the LED device, the other end of the fifth resistor and the negative output end of the PWM control constant current unit, and the negative terminal of the voltage stabilizing diode is coupled with the positive output end of the PWM control constant current unit.

Further, the first input terminal is a positive terminal, and the second input terminal is a negative terminal.

Furthermore, the PWM controlled constant current unit further includes a MOSFET tube, the MOSFET tube is disposed in the constant current control chip, the constant current control chip includes a HV pin, a CS pin, a Dra pin, and a GND pin, a gate of the MOSFET tube is connected to the constant current control chip, the Dra pin is coupled to a drain of the MOSFET tube, and the CS pin is coupled to a source of the MOSFET tube.

Further, the PWM control constant current unit further includes: the fifth control node is connected to the negative electrode output end of the rectifying and filtering unit; and one end of the third resistor is connected with the fifth control node, and the other end of the third resistor is connected with the CS pin.

Further, the PWM control constant current unit further includes: the sixth control node is connected to the positive electrode output end of the rectifying and filtering unit; and one end of the fourth resistor is connected with the sixth control node, and the other end of the fourth resistor is connected with the HV pin.

Further, the PWM control constant current unit further includes: a seventh control node connected to the Dra pin; an inductor connected between the seventh control node and the tenth control node; an eighth control node coupled to the cathode terminal of the zener diode; and the anode end of the diode is coupled with the seventh control node, and the cathode end of the diode is coupled with the eighth control node.

Further, the PWM control constant current unit further includes: and the grounding point is connected with the GND pin.

Further, the constant current control chip further comprises a power generator, a reference source, a constant current modulator, a PWM generator and a PWM driver which are connected in sequence, the constant current modulator is connected with the PWM driver, the HV pin is coupled with the power generator, the CS pin is coupled with the constant current modulator, and the grid electrode of the MOSFET is coupled with the PWM driver.

Furthermore, the rectifying and filtering unit comprises a third control node, a fourth control node, a rectifying module and a filtering module, and the rectifying module and the filtering module are connected between the third control node and the fourth control node.

Further, the rectifying module includes a first sub-diode, a second sub-diode, a third sub-diode and a fourth sub-diode connected to each other, the filtering module includes a first capacitor coupled between the third control node and the fourth control node, wherein a junction of a negative terminal of the first sub-diode and a positive terminal of the second sub-diode is connected to the first input terminal, a junction of a negative terminal of the second sub-diode and a negative terminal of the third sub-diode is connected to the third control node, a junction of a positive terminal of the third sub-diode and a negative terminal of the fourth sub-diode is connected to the second input terminal, and a junction of a positive terminal of the fourth sub-diode and a positive terminal of the first sub-diode is connected to the fourth control node.

Furthermore, the driving circuit also comprises an overvoltage protection unit which is connected between the input unit and the rectifying and filtering unit.

Furthermore, the overvoltage protection unit includes a first control node, a second control node, a first resistor, a second resistor, and a first variable resistor, wherein the first variable resistor is coupled between the first control node and the second control node, two ends of the first resistor are respectively connected to the first input terminal and the first control node, and two ends of the second resistor are respectively connected to the second input terminal and the second control node.

Further, the LED arrangement includes one or more LED indicator lights.

Further, the external power signal is an AC/DC voltage in a voltage range of 20.4V to 264V.

The utility model also provides a LED circuit, include: the above-described drive circuit; and an LED arrangement connected to the drive circuit.

Further, the LED arrangement comprises at least one LED indicator light.

Compared with the prior art, the utility model provides a drive circuit and LED circuit for driving LED device, drive circuit includes the input unit, rectification filter unit, PWM control constant current unit and output voltage current adjustment unit, the input unit is used for receiving external power signal, rectification filter unit is used for rectifying and filtering this external power signal, PWM control constant current unit is used for carrying out the steady voltage to this LED device, the stationary flow, output voltage current adjustment unit includes fifth resistance and zener diode, this LED device establishes ties with this zener diode after parallelly connected with this fifth resistance, and this zener diode's positive terminal is connected this LED device's positive terminal. The utility model discloses a drive circuit has realized super wide handing over, direct current input voltage scope around the design of LED constant current driver chip, has solved the problem that the service voltage scope is narrow, compatibility can be poor.

It should be understood that all combinations of the foregoing concepts and additional concepts described in greater detail below can be considered as part of the inventive subject matter of the present disclosure unless such concepts are mutually inconsistent. In addition, all combinations of claimed subject matter are considered a part of the inventive subject matter of this disclosure.

The foregoing and other aspects, embodiments and features of the present teachings can be more fully understood from the following description taken in conjunction with the accompanying drawings. Additional aspects of the present invention, such as features and/or advantages of exemplary embodiments, will be apparent from the description which follows, or may be learned by practice of the specific embodiments in accordance with the teachings of the present invention.

Drawings

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the invention and not to limit the invention.

The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. Embodiments of various aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

fig. 1 is a schematic circuit diagram of a driving circuit for driving an LED device according to the present invention;

fig. 2 is a schematic structural diagram of a constant current control chip in a driving circuit for driving an LED device according to the present invention.

Detailed Description

For a better understanding of the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

In this disclosure, aspects of the present invention are described with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. Embodiments of the present disclosure are not necessarily intended to include all aspects of the invention. It should be appreciated that the various concepts and embodiments described above, as well as those described in greater detail below, may be implemented in any of numerous ways, as the disclosed concepts and embodiments are not limited to any implementation. Additionally, some aspects of the present disclosure may be used alone or in any suitable combination with other aspects of the present disclosure.

One skilled in the relevant art will recognize that the embodiments may be practiced without one or more of the specific details, or with other alternative and/or additional methods, materials, or components. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of various embodiments of the invention. Similarly, for purposes of explanation, specific numbers, materials, and configurations are set forth in order to provide a thorough understanding of the embodiments of the invention. However, the invention may be practiced without specific details. Further, it should be understood that the embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale.

Referring to fig. 1, fig. 1 is a schematic circuit diagram of a driving circuit for driving an LED device according to an embodiment of the present invention. The utility model discloses a drive circuit 100 for driving LED device 200, including input unit 10, rectification filter unit 30, PWM control constant current unit 40 and output voltage current adjustment unit 50. The input unit 10 is configured to receive an external power signal, and includes a first input terminal L and a second input terminal N; the rectifying and filtering unit 30 is connected between the first input end L and the second input end N, and is configured to rectify and filter the external power signal; the PWM control constant current unit 40 includes a constant current control chip IC1, connected between the positive and negative terminals of the output terminal of the rectifying and filtering unit 30, and connected in series with the LED device 200, for stabilizing voltage and current of the LED device 200; the output voltage and current adjusting unit 50 is connected between the PWM control constant current unit 40 and the LED device 200, and includes a ninth control node 109, a tenth control node 110, a fifth resistor R5 and a zener diode ZD1, wherein the ninth control node 109 is coupled to the positive terminal of the LED device 200, the positive terminal of the zener diode ZD1 and one end of the fifth resistor R5, the tenth control node 110 is coupled to the negative terminal of the LED device 200, the other end of the fifth resistor R5 and the negative output terminal of the PWM control constant current unit 40, and the negative terminal of the zener diode ZD1 is coupled to the positive output terminal of the PWM control constant current unit 40.

From the above, the driving circuit 100 for driving the LED device 200 in the embodiment of the present invention, aiming at the problem that the existing chip drives the industrial LED device with insufficient capability, especially when the on-state voltage and current of the industrial LED device are small, the existing LED constant current driving control chip cannot be driven under the AC/DC wide voltage input, so that the output voltage and current adjusting circuit is innovatively designed, and the output voltage value of the driving chip can be improved by adjusting the parameter of the voltage regulator tube by using the method of connecting the voltage regulator diode ZD1 with the LED device in series, thereby solving the problem of small on-state voltage of the chip driven LED device; similarly, by the method of connecting the fifth resistor R5 with the LED device in parallel, the output current of the driving chip can be improved, and the current flowing through the LED lamp can be limited by adjusting the resistance value of the resistor, so that the luminous brightness of the LED lamp is changed, the application scene of multi-specification LED lamp beads is met, and the problem of small conduction current of the existing chip-driven industrial LED device is solved.

In this embodiment, the first input terminal L is a positive terminal, the second input terminal N is a negative terminal, and subsequent circuit design is performed accordingly, but not limited to this, in practical application, the first input terminal may be a negative terminal, and the second input terminal is a positive terminal, the utility model discloses only use this example to make the explanation of the whole circuit principle.

In this embodiment, external power supply signal is AC/DC (alternating current-direct current) voltage that the input voltage range is 20.4V ~ 264V, promptly the utility model discloses can realize super wide friendship, direct current input voltage range, reduce the lower limit value of power input range.

Please refer to fig. 2, fig. 2 is a schematic diagram of a module structure of a constant current control chip in a driving circuit for driving an LED device according to the present invention. In this embodiment, the PWM-controlled constant current unit 40 further includes a MOSFET M1, and the GATE of the MOSFET M1 is connected to the constant current control chip IC1, wherein the MOSFET M1 in this embodiment is embedded in the constant current control chip IC 1. As shown in fig. 1 and 2, the constant current control chip IC1 includes an HV pin, a CS pin, a Dra pin and a GND pin, the Dra pin is coupled to the drain of the MOSFET M1, and the CS pin is coupled to the source of the MOSFET M1. More details will be set forth later with respect to the constant current control chip IC 1.

In the present embodiment, the PWM-controlled constant current unit 40 further includes a fifth control node 105, a sixth control node 106, a third resistor R3 and a fourth resistor R4, as shown in fig. 1, the fifth control node 105 is connected to the negative output terminal (the fourth control point 104 described below) of the rectifying and smoothing unit 30, and the sixth control node 106 is connected to the positive output terminal (the third control point 103 described below) of the rectifying and smoothing unit 30. One end of the third resistor R3 is connected to the fifth control node 105, and the other end of the third resistor R3 is connected to the CS pin of the constant current control chip IC1, so as to adjust the output current, that is, the magnitude of the output current of the constant current control chip IC1 can be adjusted by changing the value of the third resistor R3 (sampling resistor) connected to the CS pin of the constant current control chip IC 1. One end of the fourth resistor R4 is connected to the sixth control node 106, and the other end of the fourth resistor R4 is connected to the HV pin of the constant current control chip IC1 for regulating the input voltage, i.e., the HV pin serves as a voltage input end for receiving the aforementioned ac/dc voltage and flowing into the constant current control chip IC1 through the rectifying and smoothing unit 30.

Further, the PWM-controlled constant current unit 40 further includes a seventh control node 107, an inductor L1, an eighth control node 108, and a diode D2, wherein the seventh control node 107 is connected to the Dra pin of the constant current control chip IC1, the inductor L1 is connected between the seventh control node 107 and the tenth control node 110, the eighth control node 108 is coupled to the negative terminal of the zener diode ZD1, the positive terminal of the diode D2 is coupled to the seventh control node 107, and the negative terminal of the diode D2 is coupled to the eighth control node 108. In this embodiment, the MOSFET M1 is integrated inside the constant current control chip IC1, the Dra pin of the constant current control chip IC1 is connected to the inductor L1, and the inductance of the inductor L1 is changed to adjust the on/off time, the operating switching frequency, and the like of the MOSFET M1, so that the switching loss of the chip due to input in a wide voltage range is reduced, and the problem of heat generation of the chip is reduced. The positive terminal of the diode D2 is coupled to the Dra pin and the inductor L1 through the seventh control point 107, and the diode D2 is for adjusting the performance of the energy storage circuit and preventing the current from flowing back, for example, when the MOSFET transistor M1 is turned off, the diode D2 is used to discharge the energy stored in the inductor L1. Further, the MOSFET M1(Metal Oxide Semiconductor Field effect transistor) is a 550V high voltage MOSFET.

Further, the PWM-controlled constant current unit 40 further includes a ground point G connected to the GND pin of the constant current control chip IC 1.

The constant current control chip IC1 will be described in more detail below. As shown in fig. 2, the constant current control chip IC1 further includes a power generator, a reference source, a constant current modulator, a PWM generator and a PWM driver, which are connected in sequence, wherein the constant current modulator is connected to the PWM driver, the HV pin is coupled to the power generator, the CS pin is coupled to the constant current modulator, and the GATE of the MOSFET M1 is coupled to the PWM driver. Referring to fig. 1 again, the constant current control chip IC1 in this embodiment includes eight pins, wherein the first pin is an HV pin; the second pin and the third pin are both NC pins and are interconnected; the fourth pin is a CS pin; the fifth pin and the sixth pin are both Dra pins and are commonly coupled to the seventh control point 107, and the seventh pin and the eighth pin are GND pins and are commonly connected to the ground point G.

In the present embodiment, the model of the constant current control chip IC1 is LIS9411, but the present invention is not limited thereto. The MOSFET M1 is an N-channel MOSFET. Next, the operation principle of the constant current control chip IC1 adopted in the present embodiment is further described, and the internal functions of the chip are mainly divided into the following seven parts:

(1) starting and locking: the starting and power supply technology is adopted, the bus voltage is connected through the HV pin (namely the first pin), the internal high-voltage module provides starting current and working current, and a VCC capacitor is not needed. At startup, the VDD of the chip is first charged by the line voltage through the high voltage module, and when the voltage on the VDD reaches a threshold uvlo (off), the chip starts up and starts to output pulses to drive the internal power switch. After the IC is started, the power consumption of the chip is very low, and the power can be directly supplied through the high-voltage module, so that the VDD voltage is maintained at a certain value, and the normal work of the IC is ensured.

(2) Under-voltage lockout (UVLO): an under-voltage locking hysteresis comparator is arranged in the low-voltage locking hysteresis comparator, and when the VDD voltage rises from lower than UVLO (on) to upper than UVLO (off), the chip starts to start; and locks when the VDD voltage drops from above uvlo (off) down to uvlo (on), thus forming a hysteresis window.

(3) Soft start: after each start-up, the chip gradually builds up from the lowest operating frequency to the switching frequency required for the final constant current. The whole soft start process is about 9ms or so. The soft start can inhibit current overshoot during starting so as to reduce stress borne by the LED during starting, thereby prolonging the service life of the LED. On the other hand, soft start can also suppress voltage overshoot of the drain of the internal MOSFET at start-up, thereby increasing system reliability.

(4) Leading Edge Blanking (LEB): the leading edge blanking function is integrated inside. Within 600ns before the switching tube is switched on, an interference signal of a CS pin (namely a fourth pin) is shielded, so that the internal switching tube can be well prevented from being triggered and switched off by mistake, and the stable work of a system is ensured.

(5) And (3) over-temperature adjustment: the over-temperature adjusting function is integrated inside, and the output current is gradually reduced when the driving power supply is overheated, so that the output power and the temperature rise are controlled, the temperature of the power supply is kept at a set value, and the reliability of the system is improved. The temperature point of the chip is set to 145 ℃ through overheating adjustment.

(6) CS open circuit protection: the internal integration has opened a way the protect function of CS pin, and when the CS pin of chip is opened a way, the switch tube can turn off, gets into the automatic restart protection mode. When the error condition disappears, the system automatically restores to a normal working state.

(7) Output short-circuit protection: the output short-circuit protection function is provided. Once the output is short-circuited and lasts for only about 500us, the switch is turned off inside the chip and the chip enters a locking mode, and at the moment, the system is extremely low in power consumption and almost free of heat generation, so that the system is very safe and reliable. When the short circuit state disappears, the bus voltage is required to be completely powered off, and the system can be restored to the normal working state after being powered on again.

It should be noted that the voltage input range of the constant current control chip IC1 in the PWM control constant current unit 40 of the present embodiment can meet the requirement of AC/DC 20.4V-264V, the chip interior adopts the starting and power supply technology, the input voltage can be accurately controlled in a very wide range by using the open loop peak current mode control mode, and the constant current control chip IC1 integrates the high voltage MOSFET M1 therein, so that the requirement of the ultra wide voltage range input can be realized by using very few peripheral devices.

In this embodiment, the rectifying and filtering unit 30 includes a third control node 103, a fourth control node 104, a rectifying module and a filtering module, and the rectifying module and the filtering module are connected between the third control node 103 and the fourth control node 104. Specifically, the rectifying module comprises a bridge rectifying circuit BD1 composed of a first sub-diode 31, a second sub-diode 32, a third sub-diode 33 and a fourth sub-diode 34 connected, the filtering module comprises a first capacitor C1, the first capacitor C1 is coupled between the third control node 103 and the fourth control node 104, a junction between the cathode of the first sub-diode 31 and the anode of the second sub-diode 32 is connected to the first input terminal L, a junction between the cathode of the second sub-diode 32 and the cathode of the third sub-diode 33 is connected to the third control node 103, a junction between the anode of the third sub-diode 33 and the cathode of the fourth sub-diode 34 is connected to the second input terminal N, and a junction between the anode of the fourth sub-diode 34 and the anode of the first sub-diode 31 is connected to the fourth control node 104 of the first capacitor C1. In the rectifying and filtering unit 30 of the present embodiment, the bridge rectifier circuit BD1 is used to convert the input ac power into pulsating dc power, and the first capacitor C1 is used to filter out ac pulsating components therein, so as to obtain clean dc voltage and reduce interference of ac components to the subsequent circuits. In addition, since the bridge rectifier circuit and the filter circuit are conventional technologies, the operation principle thereof will not be described in detail herein. The rectifying and filtering unit in this embodiment is a combination of a bridge rectifying circuit and a capacitor, but in other embodiments, the rectifying and filtering unit can be added, reduced or replaced according to needs.

In another embodiment, the driving circuit 100 further includes an overvoltage protection unit 20, and the overvoltage protection unit 20 is connected between the input unit 10 and the rectifying and filtering unit 30. The overvoltage protection unit 20 includes a first control node 101, a second control node 102, a first resistor R1, a second resistor R2, and a first variable resistor RV1, wherein the first variable resistor RV1 is coupled between the first control node 101 and the second control node 102. The two ends of the first resistor R1 are connected to the first input terminal L and the first control node 101, respectively, and the two ends of the second resistor R2 are connected to the second input terminal N and the second control node 102, respectively. In addition, as in the foregoing embodiment, the junction of the negative terminal of the first sub-diode 31 and the positive terminal of the second sub-diode 32 in the rectifying and smoothing unit 30 is coupled to the first control node 101, and the junction of the positive terminal of the third sub-diode 33 and the negative terminal of the fourth sub-diode 34 in the rectifying and smoothing unit 30 is coupled to the second control node 102. Preferably, the first variable resistor RV1 is a varistor. The overvoltage protection unit 20 described in this embodiment effectively eliminates the high-energy surge voltage in the input voltage, has the characteristics of fast response time to the instantaneous overvoltage, no follow current, low residual voltage, and the like, and plays a role in overvoltage protection for the subsequent circuit.

In the embodiment of the utility model provides an in, the LED device includes at least one LED pilot lamp.

The present invention further provides an LED circuit, which includes the driving circuit 100 and the LED device 200 connected to the driving circuit 100 described in all the above embodiments.

The previous description of the invention is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the present invention is not intended to be limited to the examples and designs described in the specification but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

According to the technical scheme, the utility model provides a drive circuit and LED circuit for driving LED device has creatively designed output voltage current regulating circuit, utilizes the method of establishing ties zener diode ZD1 with the LED device, can improve driver chip output voltage value through the parameter of adjusting the stabilivolt to solve the less conducting voltage's of chip drive LED device problem; similarly, by using the method of connecting the fifth resistor R5 with the LED device in parallel, the output current of the driving chip can be improved, and the current flowing through the LED lamp can be limited by adjusting the resistance value of the resistor, so that the luminous brightness of the LED lamp can be changed, the application scene of multi-specification LED lamp beads can be met, the constant-current industrial LED indicator lamp driving circuit with the ultra-wide input voltage range of AC and DC 20.4V-264V can be realized, and the problem of insufficient driving capability of the existing chip for driving the industrial LED lamp with small current and small voltage can be solved. Furthermore, the utility model discloses a constant current control chip IC 1's among the PWM control constant current unit voltage input scope can satisfy between the AC/DC 20.4V-264V, the chip is inside to have adopted start-up and power supply technique, utilize open-loop peak current mode control mode, can make input voltage realize accurate current control at extremely wide within range, the inside highly compressed MOSFET pipe of integration of constant current control chip IC1, make and utilize few peripheral device can realize the requirement of super wide voltage range input, both reduced product design cost and saved product structure design space.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention. The present invention is intended to cover by those skilled in the art various modifications and adaptations of the invention without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention is subject to the claims.

Claims

1. A driving circuit for driving an LED device, the driving circuit comprising:

the input unit is used for receiving an external power supply signal and comprises a first input end and a second input end;

the rectification filtering unit is connected between the first input end and the second input end and is used for rectifying and filtering the external power supply signal;

the PWM control constant current unit comprises a constant current control chip, is connected between the positive electrode and the negative electrode of the output end of the rectification filter unit and is connected with the LED device in series, and is used for stabilizing the voltage and the current of the LED device; and

the output voltage and current adjusting unit is connected between the PWM control constant current unit and the LED device and comprises a ninth control node, a tenth control node, a fifth resistor and a voltage stabilizing diode, wherein the ninth control node is coupled with the positive terminal of the LED device, the positive terminal of the voltage stabilizing diode and one end of the fifth resistor, the tenth control node is coupled with the negative terminal of the LED device, the other end of the fifth resistor and the negative output end of the PWM control constant current unit, and the negative terminal of the voltage stabilizing diode is coupled with the positive output end of the PWM control constant current unit.

2. The driving circuit of claim 1, wherein the first input terminal is a positive terminal and the second input terminal is a negative terminal.

3. The driving circuit of claim 1, wherein the PWM-controlled constant current unit further comprises a MOSFET transistor embedded in the constant current control chip, the constant current control chip comprises a HV pin, a CS pin, a Dra pin, and a GND pin, a gate of the MOSFET transistor is connected to the constant current control chip, the Dra pin is coupled to a drain of the MOSFET transistor, and the CS pin is coupled to a source of the MOSFET transistor.

4. The driving circuit according to claim 3, wherein the PWM-controlled constant current unit further comprises:

the fifth control node is connected to the negative electrode output end of the rectifying and filtering unit; and

and one end of the third resistor is connected with the fifth control node, and the other end of the third resistor is connected with the CS pin.

5. The driving circuit according to claim 3, wherein the PWM-controlled constant current unit further comprises:

the sixth control node is connected to the positive electrode output end of the rectifying and filtering unit; and

and one end of the fourth resistor is connected with the sixth control node, and the other end of the fourth resistor is connected with the HV pin.

6. The driving circuit according to claim 3, wherein the PWM-controlled constant current unit further comprises:

a seventh control node connected to the Dra pin;

an inductor connected between the seventh control node and the tenth control node;

an eighth control node coupled to the cathode terminal of the zener diode; and

and the anode end of the diode is coupled with the seventh control node, and the cathode end of the diode is coupled with the eighth control node.

7. The driving circuit according to claim 3, wherein the PWM-controlled constant current unit further comprises: and the grounding point is connected with the GND pin.

8. The driving circuit of claim 3, wherein the constant current control chip further comprises a power generator, a reference source, a constant current modulator, a PWM generator and a PWM driver connected in sequence, the constant current modulator is connected to the PWM driver, the HV pin is coupled to the power generator, the CS pin is coupled to the constant current modulator, and the gate of the MOSFET is coupled to the PWM driver.

9. The driving circuit of claim 1, wherein the rectifying and filtering unit comprises a third control node, a fourth control node, a rectifying module and a filtering module, and the rectifying module and the filtering module are connected between the third control node and the fourth control node.

10. The driving circuit according to claim 9, wherein the rectifying module comprises a first sub-diode, a second sub-diode, a third sub-diode and a fourth sub-diode connected to each other, the filtering module comprises a first capacitor, the first capacitor is coupled between the third control node and the fourth control node, a junction point of the negative terminal of the first sub-diode and the positive terminal of the second sub-diode is connected to the first input terminal, a junction point of the negative terminal of the second sub-diode and the negative terminal of the third sub-diode is connected to the third control node, a junction point of the positive terminal of the third sub-diode and the negative terminal of the fourth sub-diode is connected to the second input terminal, and a junction point of the positive terminal of the fourth sub-diode and the positive terminal of the first sub-diode is connected to the fourth control node.

11. The driving circuit of claim 1, further comprising an overvoltage protection unit coupled between the input unit and the rectifying and filtering unit.

12. The driving circuit of claim 11, wherein the over-voltage protection unit comprises a first control node, a second control node, a first resistor, a second resistor, and a first variable resistor, the first variable resistor is coupled between the first control node and the second control node, two ends of the first resistor are respectively connected to the first input terminal and the first control node, and two ends of the second resistor are respectively connected to the second input terminal and the second control node.

13. The driving circuit of claim 1, wherein the LED arrangement comprises at least one LED indicator light.

14. The driving circuit according to claim 1, wherein the external power signal is an ac/dc voltage in a voltage range of 20.4V to 264V.

15. An LED circuit, comprising:

a drive circuit according to any one of claims 1 to 14; and

an LED device connected to the drive circuit.