Power supply circuit and lamp

Abstract

The utility model discloses a power supply circuit and a lamp, and relates to the technical field of illumination, the power supply circuit comprises a step-down circuit, the positive pole input end of the step-down circuit is connected with the positive pole of an input power supply; the positive electrode output end of the step-down circuit is connected with the positive electrode input end of the step-up circuit; the positive pole input end of the voltage stabilizing circuit is connected with the positive pole output end of the booster circuit, and the negative poles of the step-down circuit, the booster circuit and the voltage stabilizing circuit are all grounded; the main control chip is respectively connected with the control end of the booster circuit and the control end of the voltage stabilizing circuit; the anode of the interface is connected with the anode output end of the voltage stabilizing circuit, and the cathode of the interface is grounded through the first resistor. When the voltage of the input power supply is high, the step-down circuit reduces the output; when the voltage of the input power supply is low, the step-down circuit increases the output, so that the step-down power supply output to the step-up circuit is kept within a set voltage range. Therefore, the circuit can be applied to various input power supplies with different voltages.

Description

Technical Field

[0001] The utility model relates to the technical field of lighting, in particular to a power supply circuit and a lamp. Background Art

[0002] In the existing power supply circuits, most power supply circuits can only convert a fixed initial input voltage into the required voltage during voltage conversion. When the initial input voltage changes, the voltage at the output end will also change accordingly, resulting in abnormal operation of the electrical equipment. For example, emergency lighting lamps have two application scenarios of power supply voltages, one is a low-voltage DC power supply voltage of 36V, and the other is a high-voltage AC power supply voltage of 220V. Traditional lamps cannot be compatible with both power supply voltages at the same time. They can either only work normally under the low-voltage DC power supply voltage of 36V or only work normally under the high-voltage AC power supply voltage of 220V. This leads to the situation that when users need to change the usage scenario, they can only re-purchase equipment, increasing the user's usage cost. Summary of the Utility Model

[0003] The purpose of the utility model is to provide a power supply circuit and a lamp, which enable the electrical equipment to be compatible with a variety of different power supply voltages through the methods of first step-down, then step-up, and finally voltage stabilization.

[0004] To solve the above technical problems, the utility model adopts the following technical solutions:

[0005] On the one hand, an embodiment of the utility model provides a power supply circuit, which includes: a step-down circuit, the positive input end of the step-down circuit is connected to the positive pole of the input power supply; a step-up circuit, the positive output end of the step-down circuit is connected to the positive input end of the step-up circuit; a voltage stabilization circuit, the positive input end of the voltage stabilization circuit is connected to the positive output end of the step-up circuit, and the negative poles of the step-down circuit, the step-up circuit and the voltage stabilization circuit are all grounded; a main control chip, the main control chip is respectively connected to the control end of the step-up circuit and the control end of the voltage stabilization circuit; an interface and a first resistor, the positive pole of the interface is connected to the positive output end of the voltage stabilization circuit, and the negative pole of the interface is grounded through the first resistor.

[0006] In some embodiments, the buck circuit includes a power supply chip, a first capacitor, a second capacitor, a third capacitor, a second resistor, a third resistor, a fourth resistor, and a first diode. The power supply chip uses a KP3210 power supply chip. The DRAIN pin of the power supply chip is connected to the positive pole of the input power supply. The VDD pin of the power supply chip is connected to one end of the first capacitor. The other end of the first capacitor is connected to one end of the second capacitor, the GND pin of the power supply chip, one end of the second resistor, one end of the third resistor, the positive pole of the first diode, the positive pole of the third capacitor, and the positive pole input terminal of the boost circuit. The other end of the second capacitor is connected to the negative pole of the first diode and one end of the fourth resistor. The other ends of the third resistor and the fourth resistor are connected to the FB pin of the power supply chip. The other end of the second resistor is connected to the CS pin of the power supply chip. The negative pole of the third capacitor is grounded.

[0007] In some embodiments, the buck circuit further includes a first inductor and a second diode. One end of the first inductor is connected to the negative pole of the second diode, the other end of the first capacitor, one end of the second capacitor, the GND pin of the power supply chip, one end of the second resistor, and one end of the third resistor. The other end of the first inductor is connected to the positive pole of the first diode, the positive pole of the third capacitor, and the positive pole input terminal of the boost circuit. The positive pole of the second diode is grounded.

[0008] In some embodiments, the boost circuit includes an NMOS transistor, a second inductor, a third diode, and a fourth capacitor. The source electrode of the NMOS transistor is grounded. The gate electrode of the NMOS transistor is connected to the modulation pin of the main control chip. The drain electrode of the NMOS transistor is connected to one end of the second inductor and the positive pole of the third diode. The other end of the second inductor is connected to the positive pole output terminal of the buck circuit. The negative pole of the third diode is connected to the positive pole of the fourth capacitor and the positive pole input terminal of the voltage stabilizing circuit. The negative pole of the fourth capacitor is grounded.

[0009] In some embodiments, the boost circuit further includes a first NPN transistor, a first PNP transistor, and a fifth resistor. The collector of the first NPN transistor is connected to the second power supply. The base of the first NPN transistor is connected to the base of the first PNP transistor, one end of the fifth resistor, and the modulation pin of the main control chip. The emitter of the first NPN transistor is connected to the emitter of the first PNP transistor and the gate electrode of the NMOS transistor. The other end of the fifth resistor and the collector of the first PNP transistor are grounded.

[0010] In some embodiments, the voltage stabilizing circuit includes a sixth resistor, a seventh resistor, a second PNP transistor, a third PNP transistor, and a second NPN transistor. One end of the sixth resistor and the emitter of the second PNP transistor are connected to the positive output terminal of the boost circuit. The other end of the sixth resistor is connected to the base of the second PNP transistor and the emitter of the third PNP transistor. The base of the third PNP transistor is connected to the collector of the second PNP transistor and the collector of the second NPN transistor. The collector of the third PNP transistor is connected to the positive electrode of the interface. The emitter of the second NPN transistor is grounded through the seventh resistor. The base of the second NPN transistor is connected to the control pin of the main control chip.

[0011] In some embodiments, the power supply circuit further includes an eighth resistor and a fifth capacitor. One end of the eighth resistor is connected to the negative electrode of the interface. The other end of the eighth resistor is connected to one end of the fifth capacitor and the current detection pin of the main control chip. The other end of the fifth capacitor is grounded.

[0012] In some embodiments, the power supply circuit further includes a ninth resistor, a tenth resistor, and a sixth capacitor. One end of the ninth resistor is connected to the positive electrode of the interface. The other end of the ninth resistor is connected to one end of the tenth resistor, one end of the sixth capacitor, and the voltage detection pin of the main control chip. The other end of the tenth resistor and the other end of the sixth capacitor are grounded.

[0013] In some embodiments, the power supply circuit further includes a rectifying and filtering circuit. The rectifying and filtering circuit includes a rectifier bridge, a fuse, and a seventh capacitor. The first input terminal of the rectifier bridge is connected to the first electrode of the initial power supply through the fuse. The second input terminal of the rectifier bridge is connected to the second electrode of the initial power supply. The positive output terminal of the rectifier bridge is connected to the positive electrode of the seventh capacitor and the positive input terminal of the buck circuit. The negative output terminal of the rectifier bridge is used as the ground point. The negative electrode of the seventh capacitor is grounded.

[0014] One aspect of the embodiments of the present utility model provides a lamp, and the lamp includes the power supply circuit as described above.

[0015] According to a power supply circuit and a lamp of the embodiments of the present utility model, it has at least the following beneficial effects: By using the buck circuit to step down the voltages of different input power supplies to the same voltage, then using the boost circuit to boost it to the working voltage, and finally using the voltage stabilizing circuit to stabilize the voltage, this application can be compatible with both high-voltage application scenarios and low-voltage application scenarios.

[0016] When the voltage of the input power supply is high, the buck circuit controls the output to decrease; when the voltage of the input power supply is low, the buck circuit controls the output to increase, so that the buck power supply output to the boost circuit remains within a set voltage range. Then the boost circuit boosts the buck power supply, boosts it to the working voltage and then outputs it to the voltage stabilizing circuit, and the voltage stabilizing circuit supplies power to the load after voltage stabilization. The method of bucking first and then boosting in this application enables compatibility with both high and low voltages. Moreover, the bucking situation of the buck circuit is determined according to the voltage of the input power supply, and various different voltages can be bucked to voltages within a set voltage range. Therefore, it can be applied to input power supplies with various different voltages. This application prevents the situation where users connect to the wrong application scenario, and at the same time saves the cost of users repurchasing equipment when changing the application scenario.

[0017] It should be understood that the above general description and the following detailed description are only exemplary and do not limit the present disclosure. Brief Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 It is the schematic diagram of the power supply circuit according to the embodiment. Detailed Embodiments

[0020] The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only some of the embodiments of the present utility model, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts fall within the scope of protection of the present utility model.

[0021] The terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", and "third" may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise stated, the meaning of "a plurality" is two or more.

[0022] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "connected", "installed", "connected to", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the connection inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0023] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that this disclosure will be more complete and comprehensive, and will fully convey the concept of the example embodiments to those skilled in the art. The drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repeated description will be omitted.

[0024] The technical solutions of the embodiments of the present application will be briefly described below:

[0025] According to some embodiments, as Figure 1 shown, the present application provides a power supply circuit, which includes:

[0026] A buck circuit, the positive input terminal of the buck circuit is connected to the positive pole of the input power supply VIN;

[0027] A boost circuit, the positive output terminal of the buck circuit is connected to the positive input terminal of the boost circuit;

[0028] A voltage stabilizing circuit, the positive input terminal of the voltage stabilizing circuit is connected to the positive output terminal of the boost circuit, and the negative poles of the buck circuit, the boost circuit, and the voltage stabilizing circuit are all grounded;

[0029] A main control chip U, the main control chip U is respectively connected to the control terminal of the boost circuit and the control terminal of the voltage stabilizing circuit;

[0030] An interface CON and a first resistor R1, the positive pole of the interface CON is connected to the positive output terminal of the voltage stabilizing circuit, and the negative pole of the interface CON is grounded through the first resistor R1.

[0031] The working principle of the above embodiments of the present application is that when the voltage of the input power supply VIN is too high, the buck circuit controls the output to decrease, so that the bucked power supply VIN1 is maintained within a set voltage range, and then the boost circuit boosts the bucked power supply VIN1, and after boosting to the working voltage, it outputs to the voltage stabilizing circuit, and the voltage stabilizing circuit supplies power to the load after voltage stabilization.

[0032] When the voltage of the input power supply VIN is low, the buck circuit controls the output to increase, so that the bucked power supply VIN1 remains within a set voltage range. Then, the boost circuit boosts the bucked power supply VIN1, and after boosting to the working voltage, it outputs to the voltage stabilizing circuit. After voltage stabilization by the voltage stabilizing circuit, it supplies power to the load.

[0033] Further, the voltage range of the input power supply VIN of the buck circuit can be direct current between 20V and 600V. The buck circuit can buck the DC voltage between 20V and 600V to a set voltage range. Then, the boost circuit boosts the bucked power supply VIN1, and after boosting to the working voltage, it outputs to the voltage stabilizing circuit. After voltage stabilization by the voltage stabilizing circuit, it supplies power to the load. Therefore, the power supply circuit of the present application can be applied to the input power supply VIN with a DC voltage between 20V and 600V. This prevents the situation where the user connects to the wrong application scenario, and at the same time saves the cost for the user to repurchase equipment when changing the application scenario.

[0034] The following further elaborates on the preferred embodiments of the present disclosure in conjunction with the Figure 1 accompanying drawings of this specification.

[0035] According to some embodiments, as Figure 1 shown, the buck circuit includes a power chip U, a first capacitor C1, a second capacitor C2, a third capacitor C3, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first diode D1. The power chip U uses a KP3210 power chip U. The DRAIN pin of the power chip U is connected to the positive pole of the input power supply VIN. The VDD pin of the power chip U is connected to one end of the first capacitor C1. The other end of the first capacitor C1 is connected to one end of the second capacitor C1, the GND pin of the power chip U, one end of the second resistor R2, one end of the third resistor R3, the positive pole of the first diode D1, the positive pole of the third capacitor C3, and the positive input terminal of the boost circuit. The other end of the second capacitor C2 is connected to the negative pole of the first diode D1 and one end of the fourth resistor R4. The other ends of the third resistor R3 and the fourth resistor R4 are connected to the FB pin of the power chip U. The other end of the second resistor R2 is connected to the CS pin of the power chip U. The negative pole of the third capacitor C3 is grounded.

[0036] Among them, the input voltage range of the DRAIN pin of the power chip U can be direct current between 20V and 600V.

[0037] The working principle based on the above embodiments is as follows: The CS pin of the power supply chip U serves as the output pin. The CS pin outputs the buck power supply VIN1 through the third resistor R3. The GND pin serves as the ground loop pin of the power supply chip U, and the FB pin serves as the feedback pin of the power supply chip U. When the voltage of the input power supply VIN is too high, the power supply chip U reduces the output of the CS pin, so that the bucked buck power supply VIN1 is maintained within the set voltage range. Then, the boost circuit boosts the buck power supply VIN1, and after boosting to the working voltage, it outputs to the voltage stabilizing circuit. After voltage stabilization by the voltage stabilizing circuit, it supplies power to the load.

[0038] When the voltage of the input power supply VIN is low, the power supply chip U increases the output of the CS pin, so that the bucked buck power supply VIN1 is maintained within the set voltage range. Then, the boost circuit boosts the buck power supply VIN1, and after boosting to the working voltage, it outputs to the voltage stabilizing circuit. After voltage stabilization by the voltage stabilizing circuit, it supplies power to the load.

[0039] Further, as Figure 1 shown, in addition to the above embodiments, the buck circuit further includes a first inductor L1 and a second diode D2. One end of the first inductor L1 is connected to the negative electrode of the second diode D2, the other end of the first capacitor C1, one end of the second capacitor C2, the GND pin of the power supply chip U, one end of the second resistor R2, and one end of the third resistor R3. The other end of the first inductor L1 is connected to the positive electrode of the first diode D1, the positive electrode of the third capacitor C3, and the second inductor L2. The positive electrode of the second diode D2 is grounded.

[0040] Among them, the other end of the first inductor L1 outputs the buck power supply VIN1.

[0041] According to some embodiments, as Figure 1 shown, the boost circuit includes an NMOS transistor Q10, a second inductor L2, a third diode D3, and a fourth capacitor C4. The source electrode of the NMOS transistor Q10 is grounded. The gate electrode of the NMOS transistor Q10 is connected to the modulation pin PWM of the main control chip U. The drain electrode of the NMOS transistor Q10 is connected to one end of the second inductor L2 and the positive electrode of the third diode D3. The other end of the second inductor L2 is connected to the positive output terminal of the buck circuit. The negative electrode of the third diode D3 is connected to the positive electrode of the fourth capacitor C4, one end of the sixth resistor R6, and the emitter of the second PNP transistor QP2. The negative electrode of the fourth capacitor C4 is grounded.

[0042] Among them, the modulation pin PWM of the main control chip U outputs a PWM signal to control the boost circuit to perform boost operation.

[0043] Further, as Figure 1As shown, in addition to the above embodiments, the boost circuit further includes a first NPN transistor QN1, a first PNP transistor QP1, and a fifth resistor R5. The collector of the first NPN transistor QN1 is connected to the second power supply VCC. The base of the first NPN transistor QN1 is connected to the base of the first PNP transistor QP1, one end of the fifth resistor R5, and the modulation pin PWM of the main control chip U. The emitter of the first NPN transistor QN1 is connected to the emitter of the first PNP transistor QP1 and the gate of the NMOS transistor Q10. The other end of the fifth resistor R5 and the collector of the first PNP transistor QP1 are grounded.

[0044] Among them, the modulation pin PWM of the main control chip U outputs a PWM signal to control the switching conduction of the first NPN transistor QN1 and the first PNP transistor QP1, so that the boost circuit performs boost operation.

[0045] According to some embodiments, as Figure 1 As shown, the voltage stabilizing circuit includes a sixth resistor R6, a seventh resistor R7, a second PNP transistor QP2, a third PNP transistor QP3, and a second NPN transistor QN2. One end of the sixth resistor R6 and the emitter of the second NPN transistor QN2 are connected to the positive output terminal of the boost circuit. The other end of the sixth resistor R6 is connected to the base of the second PNP transistor QP2 and the emitter of the third PNP transistor QP3. The base of the third PNP transistor QP3 is connected to the collector of the second PNP transistor QP2 and the collector of the second NPN transistor QN2. The collector of the third PNP transistor QP3 is connected to the positive pole of the interface CON. The emitter of the second NPN transistor QN2 is grounded through the seventh resistor R7. The base of the second NPN transistor QN2 is connected to the control pin KG of the main control chip U.

[0046] Among them, when the load is working, the control pin KG of the main control chip U outputs a high-level signal to the base of the second NPN transistor QN2, the third PNP transistor QP3 conducts, and the second PNP transistor QP2 conducts. The second PNP transistor QP2 and the third PNP transistor QP3 are used for voltage stabilization, and the second NPN transistor QN2 is used for switching and regulation.

[0047] According to some embodiments, as Figure 1 As shown, the power supply circuit further includes an eighth resistor R8 and a fifth capacitor C5. One end of the eighth resistor R8 is connected to the negative pole of the interface CON. The other end of the eighth resistor R8 is connected to one end of the fifth capacitor C5 and the current detection pin I_LED of the main control chip U. The other end of the fifth capacitor C5 is grounded.

[0048] Among them, the main control chip U detects the working current of the load through the current detection pin I_LED.

[0049] According to some embodiments, asFigure 1 As shown, the power supply circuit further includes a ninth resistor R9, a tenth resistor R10, and a sixth capacitor C6. One end of the ninth resistor R9 is connected to the positive electrode of the interface CON, and the other end of the ninth resistor R9 is connected to one end of the tenth resistor R10, one end of the sixth capacitor C6, and the voltage detection pin V_LED of the main control chip U. The other end of the tenth resistor R10 and the other end of the sixth capacitor C6 are grounded.

[0050] Among them, the main control chip U detects the working voltage of the load through the voltage detection pin V_LED.

[0051] According to some embodiments, as Figure 1 shown, the power supply circuit further includes a rectifying and filtering circuit. The rectifying and filtering circuit includes a rectifier bridge DB, a fuse F, and a seventh capacitor C7. The first input terminal of the rectifier bridge DB is connected to the first electrode of the initial power supply PWR through the fuse F, the second input terminal of the rectifier bridge DB is connected to the second electrode of the initial power supply PWR, the positive output terminal of the rectifier bridge DB is connected to the positive electrode of the seventh capacitor C7 and the DRAIN pin of the power supply chip U, the negative output terminal of the rectifier bridge DB is used as the ground, and the negative electrode of the seventh capacitor C7 is grounded.

[0052] Among them, after using the rectifier bridge DB, the initial power supply PWR can be connected in the forward or reverse direction without worrying about reverse connection, and there is no need to set an anti-reverse connection structure. And the initial power supply PWR can be either alternating current or direct current. Combining with the characteristics of the KP3210 power supply chip U of the present application, the voltage of the input power supply VIN after rectifying and filtering by the rectifying and filtering circuit can be between 20V and 600V. This greatly improves the usage range of the power supply circuit of the present application.

[0053] The working principle of the present application is that when the voltage of the input power supply VIN is too high, the power supply chip U reduces the output of the CS pin, so that the bucked-down power supply VIN1 is maintained within a set voltage range. Then the boost circuit boosts the bucked-down power supply VIN1, and after boosting to the working voltage, it outputs to the voltage stabilizing circuit. The voltage stabilizing circuit stabilizes the voltage and supplies power to the load.

[0054] When the voltage of the input power supply VIN is low, the power supply chip U increases the output of the CS pin, so that the bucked-down power supply VIN1 is maintained within a set voltage range. Then the boost circuit boosts the bucked-down power supply VIN1, and after boosting to the working voltage, it outputs to the voltage stabilizing circuit. The voltage stabilizing circuit stabilizes the voltage and supplies power to the load.

[0055] When the main control chip U detects an abnormal working current of the load through the current detection pin I_LED, and / or when the main control chip U detects an abnormal working voltage of the load through the voltage detection pin V_LED, the main control chip U controls the modulation pin PWM and the control pin KG to output low-level signals, the boost circuit stops boosting, the voltage stabilization circuit is turned off, and the load is de-energized, protecting the load and the power supply circuit and preventing faults such as short circuits and high voltages from damaging the power supply circuit or the load.

[0056] According to some embodiments, a lighting fixture includes the power supply circuit as described above.

[0057] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any one or more embodiments or examples in a suitable manner.

[0058] Although the present disclosure has been described with reference to several exemplary embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present disclosure can be embodied in many forms without departing from the spirit or essence of the present application, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be construed broadly within the spirit and scope defined by the appended claims. Therefore, all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A power supply circuit, characterized in that: The power supply circuit comprises: A step-down circuit, wherein a positive input terminal of the step-down circuit is connected to a positive electrode of an input power source; A boost circuit, wherein the positive output terminal of the buck circuit is connected to the positive input terminal of the boost circuit; A voltage stabilizing circuit, wherein the positive input terminal of the voltage stabilizing circuit is connected to the positive output terminal of the boost circuit, and the negative electrodes of the buck circuit, the boost circuit and the voltage stabilizing circuit are all grounded; A main control chip, wherein the main control chip is respectively connected to a control end of the boost circuit and a control end of the voltage stabilizing circuit; An interface and a first resistor, wherein the positive electrode of the interface is connected to the positive output terminal of the voltage stabilizing circuit, and the negative electrode of the interface is grounded through the first resistor.

2. The power supply circuit according to claim 1, characterized in that: The step-down circuit includes a power chip, a first capacitor, a second capacitor, a third capacitor, a second resistor, a third resistor, a fourth resistor and a first diode. The power chip adopts a KP3210 power chip. The DRAIN pin of the power chip is connected to the positive electrode of the input power supply, the VDD pin of the power chip is connected to one end of the first capacitor, the other end of the first capacitor is connected to one end of the second capacitor, the GND pin of the power chip, one end of the second resistor, one end of the third resistor, the positive electrode of the first diode, the positive electrode of the third capacitor and the positive input end of the boost circuit, the other end of the second capacitor is connected to the negative electrode of the first diode and one end of the fourth resistor, the other end of the third resistor and the other end of the fourth resistor are connected to the FB pin of the power chip, the other end of the second resistor is connected to the CS pin of the power chip, and the negative electrode of the third capacitor is grounded.

3. The power supply circuit according to claim 2, characterized in that: The step-down circuit also includes a first inductor and a second diode, one end of the first inductor is connected to the cathode of the second diode, the other end of the first capacitor, one end of the second capacitor, the GND pin of the power chip, one end of the second resistor and one end of the third resistor, the other end of the first inductor is connected to the anode of the first diode, the anode of the third capacitor and the positive input terminal of the boost circuit, and the anode of the second diode is grounded.

4. The power supply circuit according to claim 1, characterized in that: The boost circuit includes an NMOS tube, a second inductor, a third diode and a fourth capacitor. The source of the NMOS tube is grounded, the gate of the NMOS tube is connected to the modulation pin of the main control chip, the drain of the NMOS tube is connected to one end of the second inductor and the positive electrode of the third diode, the other end of the second inductor is connected to the positive output end of the step-down circuit, the cathode of the third diode is connected to the positive electrode of the fourth capacitor and the positive input end of the voltage stabilizing circuit, and the cathode of the fourth capacitor is grounded.

5. The power supply circuit according to claim 4, characterized in that: The boost circuit also includes a first NPN transistor, a first PNP transistor and a fifth resistor, the collector of the first NPN transistor is connected to the second power supply, the base of the first NPN transistor is connected to the base of the first PNP transistor, one end of the fifth resistor and the modulation pin of the main control chip, the emitter of the first NPN transistor is connected to the emitter of the first PNP transistor and the gate of the NMOS tube, and the other end of the fifth resistor and the collector of the first PNP transistor are grounded.

6. The power supply circuit according to claim 1, characterized in that: The voltage stabilizing circuit includes a sixth resistor, a seventh resistor, a second PNP transistor, a third PNP transistor and a second NPN transistor, one end of the sixth resistor and the emitter of the second PNP transistor are connected to the positive output end of the boost circuit, the other end of the sixth resistor is connected to the base of the second PNP transistor and the emitter of the third PNP transistor, the base of the third PNP transistor is connected to the collector of the second PNP transistor and the collector of the second NPN transistor, the collector of the third PNP transistor is connected to the positive electrode of the interface, the emitter of the second NPN transistor is grounded through the seventh resistor, and the base of the second NPN transistor is connected to the control pin of the main control chip.

7. The power supply circuit according to claim 1, characterized in that: The power supply circuit also includes an eighth resistor and a fifth capacitor, one end of the eighth resistor is connected to the negative electrode of the interface, the other end of the eighth resistor is connected to one end of the fifth capacitor and the current detection pin of the main control chip, and the other end of the fifth capacitor is grounded.

8. The power supply circuit according to claim 1, characterized in that: The power supply circuit also includes a ninth resistor, a tenth resistor and a sixth capacitor, one end of the ninth resistor is connected to the positive pole of the interface, the other end of the ninth resistor is connected to one end of the tenth resistor, one end of the sixth capacitor and the voltage detection pin of the main control chip, and the other end of the tenth resistor and the other end of the sixth capacitor are grounded.

9. The power supply circuit according to claim 1, characterized in that: The power supply circuit also includes a rectifier and filter circuit, which includes a rectifier bridge, a fuse and a seventh capacitor. The first input end of the rectifier bridge is connected to the first electrode of the initial power supply through the fuse, the second input end of the rectifier bridge is connected to the second electrode of the initial power supply, the positive output end of the rectifier bridge is connected to the positive electrode of the seventh capacitor and the positive input end of the step-down circuit, the negative output end of the rectifier bridge is used as a ground point, and the negative electrode of the seventh capacitor is grounded.

10. A lamp, characterized in that: The lamp comprises a power supply circuit as claimed in any one of claims 1 to 9.

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