Short-circuit protection control circuit, LED driving power supply and lamp

Abstract

The utility model discloses a short-circuit protection control circuit, which is applied to an LED driving power supply, and comprises a detection protection circuit and a main control chip connected with an LED light source and the LED driving power supply, and the detection protection circuit is used for acquiring voltage at the positive and negative ends of an LED lamp string in the LED light source, detecting the magnitude of the acquired voltage and preset reference voltage, and outputting the detected voltage. The main control chip outputs a control signal to an LED driving circuit of an LED driving power supply according to the acquired voltage and a preset reference voltage so as to close the LED driving circuit; and the threshold value control circuit is connected with the main control chip and is used for sending the number of the lamp beads in the LED lamp string to the main control chip according to an external instruction, so that the main control chip adjusts the preset reference voltage according to the number of the lamp beads. The utility model also discloses an LED driving power supply and a lamp.

Description

Technical Field

[0001] The utility model relates to the technical field of LED lighting, and more specifically to a short-circuit protection control circuit, an LED driving power supply and a lamp. Background Art

[0002] With the advancement of technology and the improvement of people's living standards, smart home products have gradually entered the lives of ordinary people. Intelligent home products are becoming more and more popular among consumers. Traditional lighting fixtures have also gradually completed the transformation from traditional energy-saving lamps to energy-saving, environmentally friendly, and long-life LED lamps, and then to intelligent LED lamps. With the upgrading of consumption, intelligent lighting products will gradually become mainstream products.

[0003] In the prior art, LED driver power supplies driven by constant voltage lamp strip controllers or some high-power external MOS tubes often have the phenomenon of output MOS tubes in their LED driver circuits being damaged due to output circuit short circuits. Although a short-circuit protection function is provided in the front-stage power supply of such LED driver power supplies, the protection function has defects, which may cause frequent hiccups in the LED driver power supply. At present, in order to prevent the MOS tube from being damaged by over-temperature due to frequent switching, a hardware protection circuit is added to the back stage to turn off the MOS tube in time when the output is short-circuited. However, this protection also has shortcomings. For example, once the parameters of the hardware protection circuit are designed, the detection voltage threshold will be fixed. When there are fewer LED lamp beads in series, it is impossible to identify whether the voltage rise is caused by the short circuit or the clamping voltage rise, which may cause false detection and trigger short-circuit protection, resulting in the LED driver power supply failing to work properly. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a short-circuit protection control circuit, an LED driving power supply and a lamp, so that when the number of lamp beads in the LED lamp string is reduced, it can also correctly detect whether the LED lamp string is short-circuited, and shut down the operation of the LED driving circuit in the event of a short circuit, thereby protecting the MOS tube, so that the LED driving power supply and the lamp can work normally.

[0005] In order to solve the above technical problems, according to one aspect of the utility model, a short circuit protection control circuit is provided, which is applied to an LED driving power supply and includes:

[0006] A detection protection circuit is connected to the main control chip of the LED light source and the LED driving power supply, and is used to obtain the voltage at the positive and negative ends of the LED light string in the LED light source, and detect the magnitude of the obtained voltage and a preset reference voltage, so that the main control chip outputs a control signal to the LED driving circuit of the LED driving power supply according to the magnitude of the obtained voltage and the preset reference voltage to turn off the LED driving circuit;

[0007] The threshold control circuit is connected to the main control chip and is used to send the number of lamp beads in the LED lamp string to the main control chip according to an external instruction, so that the main control chip adjusts the preset reference voltage according to the number of lamp beads.

[0008] Its further technical solution is: the threshold control circuit includes a communication module, which is connected to the external intelligent device and the main control chip, and is used to send the number of lamp beads in the LED lamp string contained in the external instruction from the external intelligent device to the main control chip.

[0009] A further technical solution is: the communication module includes an NFC chip.

[0010] Its further technical solution is: the detection protection circuit includes a resistor voltage divider circuit and a comparison circuit, wherein the input end of the resistor voltage divider circuit is connected to the LED light source, and the input end of the comparison circuit is connected to the output end of the resistor voltage divider circuit, and is used to compare whether the output voltage of the resistor voltage divider circuit is greater than a preset reference voltage, and when the output voltage is greater than the preset reference voltage, the main control chip turns off the LED drive circuit.

[0011] Its further technical solution is: the resistance voltage divider circuit includes a first resistor, a third resistor and a fourth resistor, wherein one end of the first resistor is connected to the positive pole of the LED light string in the LED light source, and the other end thereof is connected to the negative pole of the LED light string and one end of the third resistor, the other end of the third resistor is connected to one end of the fourth resistor and the comparison circuit, and the other end of the fourth resistor is grounded.

[0012] Its further technical solution is: the comparison circuit includes a first operational amplifier, the inverting input terminal of the first operational amplifier is connected to the output terminal of the resistance voltage divider circuit, and the non-inverting input terminal and output terminal of the first operational amplifier are both connected to the main control chip.

[0013] Its further technical solution is: the comparison circuit also includes an RC filter circuit, the RC filter circuit includes a first capacitor and a fifth resistor, one end of the fifth resistor is connected to the in-phase input terminal of the first operational amplifier and one end of the first capacitor, the other end of the fifth resistor is connected to the main control chip, and the other end of the first capacitor is grounded.

[0014] In order to solve the above technical problems, the utility model also provides a short circuit protection control circuit, which is applied to an LED driving power supply. The short circuit protection control circuit includes:

[0015] A detection protection circuit is connected to the LED light source, and is used to obtain the voltage at the positive and negative ends of the LED light string in the LED light source, and detect the magnitude of the obtained voltage and a preset reference voltage;

[0016] MCU, connected to the detection protection circuit and the main control chip of the LED driving power supply, used for providing a preset reference voltage, and sending a control instruction to the main control chip according to the magnitude of the acquired voltage and the preset reference voltage, so that the main control chip turns off the LED driving circuit;

[0017] The threshold control circuit is connected to the MCU and is used to send the number of lamp beads in the LED lamp string to the MCU according to an external instruction, so that the MCU adjusts the preset reference voltage according to the number of lamp beads.

[0018] To solve the above technical problems, according to another aspect of the present invention, an LED driving power supply is provided, the LED driving power supply comprising an LED driving circuit, a main control chip and the above short circuit protection control circuit, wherein:

[0019] The LED driving circuit is connected between the power input terminal and the LED light source, and is used to adjust the current input to the LED light source and shut off the current input to the LED light source according to the input control signal. The LED light source includes at least one LED light string.

[0020] The main control chip is connected to the LED driving circuit and is used to output a control signal to the LED driving circuit to control the operation of the LED driving circuit;

[0021] The short-circuit protection control circuit is connected to the LED light string and the main control chip, and is used to send the number of lamp beads in the LED light string to the main control chip according to an external instruction, so that the main control chip adjusts the preset reference voltage provided according to the number of lamp beads, and obtains the voltage across the positive and negative poles of the LED light string, detects the size of the obtained voltage and the preset reference voltage, so that the main control chip outputs a control signal to the LED drive circuit according to the size of the obtained voltage and the preset reference voltage to turn off the LED drive circuit; or, it is used to adjust the preset reference voltage according to the number of lamp beads in the LED light string in the external instruction, and obtains the voltage across the positive and negative poles of the LED light string, detects the size of the obtained voltage and the preset reference voltage, and sends a control instruction to the main control chip according to the size of the obtained voltage and the preset reference voltage, so that the main control chip turns off the LED drive circuit.

[0022] In order to solve the above technical problems, the utility model also provides a lamp, which includes the above LED driving power supply.

[0023] Compared with the prior art, the short-circuit protection control circuit of the utility model is provided with a detection protection circuit for obtaining the voltage at the positive and negative ends of the LED light string in the LED light source, and detecting the size of the obtained voltage and the preset reference voltage. At the same time, a threshold control circuit is also provided. The threshold control circuit and the main control chip can cooperate to adjust the preset reference voltage provided according to the number of lamp beads in the LED light string, that is, when the number of lamp beads in the LED light string decreases, the preset reference voltage used for comparison in the detection protection circuit will be adjusted accordingly, so that when the number of lamp beads decreases, it is also possible to detect whether the LED light string is short-circuited based on the voltage at the positive and negative ends of the LED light string obtained, and shut down the operation of the LED driving circuit in the event of a short circuit, protect the MOS tube, and avoid erroneous identification caused by the reduction of lamp beads. It can be seen that the short-circuit protection control circuit of the utility model is suitable for lamps with different numbers of lamp beads, and short-circuit identification and protection of LED driving power supplies with different numbers of lamp beads can be achieved without changing the hardware design, so that the LED driving power supply and the lamp can work normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a circuit block diagram of the first embodiment of the LED driving power supply of the utility model.

[0025] Figure 2 This is a circuit diagram of the first embodiment of the LED driving power supply of the utility model.

[0026] Figure 3 This is a circuit diagram of the second embodiment of the LED driving power supply of the utility model. DETAILED DESCRIPTION

[0027] In order to enable ordinary technicians in the field to more clearly understand the purpose, technical solutions and advantages of the utility model, the utility model is further explained below in conjunction with the accompanying drawings and embodiments.

[0028] Reference Figure 1 to Figure 2 , Figure 1 to Figure 2The first embodiment of the LED driving power supply 100 of the utility model is shown. In the embodiment shown in the accompanying drawings, the LED driving power supply 100 includes an LED driving circuit 11, a main control chip 12 and a short circuit protection control circuit 13, wherein the LED driving circuit 11 is connected between the power input terminal VIN and the LED light source 200, and is used to adjust the current input to the LED light source 200, and cut off the current input to the LED light source 200 according to the input control signal, and the LED light source 200 includes at least one LED light string; the main control chip 12 is connected to the LED driving circuit 11, and is used to output a control signal to the LED driving circuit 11. 1 to control the operation of the LED driving circuit 11; the short-circuit protection control circuit 13 is connected to the LED light string and the main control chip 12, and is used to send the number of lamp beads in the LED light string to the main control chip 12 according to an external instruction, so that the main control chip 12 adjusts the preset reference voltage provided according to the number of lamp beads, and obtains the voltage at both ends of the positive and negative poles of the LED light string, detects the magnitude of the obtained voltage and the preset reference voltage, so that the main control chip 12 outputs a control signal to the LED driving circuit 11 according to the magnitude of the obtained voltage and the preset reference voltage to turn off the LED driving circuit 11. It can be understood that the LED driving circuit 11 of the utility model includes an output MOS tube, and the LED driving circuit 11 is a commonly used LED driving circuit for those skilled in the art, which will not be described in detail here. Based on the above design, the LED driving power supply 100 of the utility model is suitable for lamps with different numbers of lamp beads, and short-circuit identification and protection of LED driving power supplies 100 with different numbers of lamp beads can be achieved without changing the hardware design, that is, by cooperating with the main control chip 12 through the added short-circuit protection control circuit 13, the preset reference voltage provided can be adjusted according to the number of lamp beads in the LED light string, that is, when the number of lamp beads in the LED light string is reduced, the preset reference voltage will be adjusted accordingly, so that when the number of lamp beads is reduced, it is also possible to detect whether the LED light string is short-circuited based on the voltage across the positive and negative poles of the LED light string, and shut down the LED driving circuit 11 when a short circuit occurs, thereby protecting the MOS tube well to prevent short-circuit damage and avoiding incorrect identification caused by a reduction in lamp beads.

[0029] Continue to refer to Figure 2In some embodiments, the short-circuit protection control circuit 13 includes a detection protection circuit and a threshold control circuit 132, wherein the detection protection circuit is connected to the LED light source 200 and the main control chip 12 of the LED driving power supply 100, and is used to obtain the voltage at the positive and negative ends of the LED light string in the LED light source 200, and detect the size of the obtained voltage and the preset reference voltage, so that the main control chip 12 outputs a control signal to the LED driving circuit 11 of the LED driving power supply 100 according to the size of the obtained voltage and the preset reference voltage to turn off the LED driving circuit 11; the threshold control circuit 132 is connected to the main control chip 12, and is used to send the number of lamp beads in the LED light string to the main control chip 12 according to an external instruction, so that the main control chip 12 adjusts the preset reference voltage according to the number of lamp beads. Based on the above design, the short-circuit protection control circuit 13 of the utility model has a simple structure. When in use, it connects all LED light strings in the LED light source 200. When the number of lamp beads in the LED light string changes, the threshold control circuit 132 cooperates with the main control chip 12 to adjust the preset reference voltage in the detection protection circuit according to the number of lamp beads in the externally input LED light string, thereby avoiding erroneous identification caused by a reduction in the number of lamp beads.

[0030] Specifically, in this embodiment, the threshold control circuit 132 includes a communication module, which is connected to the external smart device and the main control chip 12, and is used to send the number of lamp beads in the LED light string contained in the external instruction from the external smart device to the main control chip 12. Preferably, the communication module includes an NFC chip, which is connected to two data pins of the main control chip 12 for communication. Based on the above design, the number of LED lamp beads is written to the main control chip 12 through the NFC chip, so that the main control chip 12 adjusts the preset reference voltage provided to the detection protection circuit.

[0031] In some embodiments, the detection protection circuit includes a resistor voltage divider circuit 1311 and a comparison circuit 1312, wherein the input end of the resistor voltage divider circuit 1311 is connected to the LED light source 200, and the input end of the comparison circuit 1312 is connected to the output end of the resistor voltage divider circuit 1311, and is used to compare whether the output voltage of the resistor voltage divider circuit 1311 is greater than a preset reference voltage, and when the output voltage is greater than the preset reference voltage, the main control chip 12 turns off the LED driving circuit 11.

[0032] Specifically, the resistor voltage divider circuit 1311 includes a first resistor R1, a third resistor R3 and a fourth resistor R4, wherein one end of the first resistor R1 is connected to the positive electrode of the LED light string in the LED light source 200, and the other end thereof is connected to the negative electrode of the LED light string and one end of the third resistor R3, the other end of the third resistor R3 is connected to one end of the fourth resistor R4 and the comparison circuit 1312, and the other end of the fourth resistor R4 is grounded. Based on the above design, when the number of lamp beads decreases or the LED light string is short-circuited, the voltage at the connection point between the first resistor R1 and the negative electrode of the LED light string will rise.

[0033] In some embodiments, the comparison circuit 1312 includes a first operational amplifier U1 and an RC filter circuit, the RC filter circuit includes a first capacitor C1 and a fifth resistor R5, the inverting input terminal of the first operational amplifier U1 is connected to the output terminal of the resistor divider circuit 1311, that is, the end connected to the third resistor R3 and the fourth resistor R4, the output terminal of the first operational amplifier U1 is connected to an input pin of the main control chip 12, one end of the fifth resistor R5 is connected to the in-phase input terminal of the first operational amplifier U1 and one end of the first capacitor C1, the other end of the fifth resistor R5 is connected to an output pin of the main control chip 12, and the other end of the first capacitor C1 is grounded. In this embodiment, the positive power supply terminal of the first operational amplifier U1 is also connected to the power supply VCC, and the output terminal of the first operational amplifier U1 is also connected to the power supply VCC through a second resistor R2. Based on the above design, when the number of LED lamp beads is written, the main control chip 12 will change the duty cycle of the PWM output to the first operational amplifier U1 according to the value, and change the voltage value of the preset reference voltage input to the common-phase input terminal of the first operational amplifier U1 through the RC filter circuit composed of the first capacitor C1 and the fifth resistor R5.

[0034] Understandably, in the LED driving power supply 100 of the present invention, when the number of LED lamp beads decreases or the LED lamp string is short-circuited, such as Figure 2As shown, the voltage V1 in the resistor voltage divider circuit 1311 will rise until the voltage at VLED is equal to V1, and the voltage V2 at the connection between the resistor voltage divider circuit 1311 and the inverting input terminal of the first operational amplifier U1 will rise as V1 rises. In order to avoid the voltage at the inverting input terminal of the first operational amplifier U1 being greater than the preset reference voltage at the inverting input terminal due to the reduction in the number of LED lamp beads, thereby triggering short-circuit protection, the utility model is also designed with a threshold control circuit 132. The number of LED light strings can be written into the main control chip 12 of the LED driving power supply 100 through the NFC chip in the threshold control circuit 132. The main control chip 12 will The duty cycle of the PWM output to the first operational amplifier U1 is changed by the RC filtering circuit, and the voltage value of the preset reference voltage V3 input to the non-inverting input terminal of the first operational amplifier U1 is changed. For example, when the number of LED light strings decreases, the main control chip 12 increases the duty cycle of the PWM and increases the voltage value of the preset reference voltage, thereby avoiding incorrect recognition caused by the reduction of lamp beads. After the preset reference voltage V3 is adjusted and the LED light string is short-circuited, the voltage V2 is greater than the preset reference voltage V3. At this time, the first operational amplifier U1 outputs a low level to the main control chip 12, triggering the short-circuit protection. The control EN pin of the main control chip 12 outputs a control signal to turn off the LED drive circuit 11.

[0035] In summary, the short-circuit protection control circuit 13 of the utility model is suitable for lamps with different numbers of lamp beads, and short-circuit identification and protection of LED driving power supplies 100 with different numbers of lamp beads can be achieved without changing the hardware design, so that the LED driving power supply 100 can work normally, that is, when the number of lamp beads in the LED lamp string is reduced, it can also correctly detect whether the LED lamp string is short-circuited, and shut down the operation of the LED driving circuit 11 when a short circuit occurs, which can well protect the MOS tube in the LED driving circuit 11 to prevent short-circuit damage.

[0036] Reference Figure 3 , Figure 3This is a circuit diagram of the second embodiment of the LED driving power supply 100 of the utility model. The difference between this embodiment and the above-mentioned first embodiment is that the short-circuit protection control circuit 13 adds an MCU 133 for providing and adjusting the preset reference voltage, and the specific connection between the short-circuit protection control circuit 13 and the main control chip 12 is different, and the remaining circuit structures are the same or similar. In this embodiment, the short-circuit protection control circuit 13 is used to adjust the preset reference voltage according to the number of lamp beads of the LED light string in the external instruction, and obtain the voltage at the positive and negative ends of the LED light string, detect the size of the obtained voltage and the preset reference voltage, and send a control instruction to the main control chip 12 according to the size of the obtained voltage and the preset reference voltage, so that the main control chip 12 turns off the LED driving circuit 11. Specifically, the short-circuit protection control circuit 13 includes a detection protection circuit, an MCU 133 and a threshold control circuit 132, wherein the detection protection circuit is connected to the LED light source 200, and is used to obtain the voltage at the positive and negative ends of the LED lamp string in the LED light source 200, and detect the size of the obtained voltage and a preset reference voltage; the MCU 133 is connected to the detection protection circuit and the main control chip 12 of the LED driving power supply 100, and is used to provide a preset reference voltage, and send a control instruction to the main control chip 12 according to the size of the obtained voltage and the preset reference voltage, so that the main control chip 12 turns off the LED driving circuit 11; the threshold control circuit 132 is connected to the MCU 133, and is used to send the number of lamp beads in the LED lamp string to the MCU 133 according to an external instruction, so that the MCU 133 adjusts the preset reference voltage according to the number of lamp beads. It can be understood that in the present embodiment, the short-circuit protection control circuit 13 is additionally provided with an MCU 133, and some functions of the main control chip 12 in the first embodiment are implemented in the additionally provided MCU 133, that is, the MCU 133 in the short-circuit protection control circuit 13 implements the provision and adjustment of the preset reference voltage, and sends a control instruction to the main control chip 12 when the LED is short-circuited to trigger the short-circuit protection and turn off the LED driving circuit 11. Similarly, short-circuit identification and protection of LED driving power supplies 100 with different numbers of lamp beads can be realized, so that the LED driving power supply 100 can work normally.

[0037] The utility model also provides a lamp, which includes the LED driving power supply 100 described in the first embodiment and the second embodiment. When the number of lamp beads in the LED lamp string is reduced, it can also correctly detect whether the LED lamp string is short-circuited, and shut down the operation of the LED driving circuit 11 when a short circuit occurs. The MOS tube in the LED driving circuit 11 can be well protected to prevent short-circuit damage, thereby protecting the LED driving power supply 100 and the lamp.

[0038] The above description is only a preferred embodiment of the utility model, and does not limit the utility model in any form. Those skilled in the art can make various equivalent changes and improvements based on the above embodiments, and all equivalent changes or modifications made within the scope of the claims should fall within the protection scope of the utility model.

Claims

1. A short circuit protection control circuit, applied to LED driving power supply, characterized in that: The short circuit protection control circuit comprises: A detection protection circuit is connected to the main control chip of the LED light source and the LED driving power supply, and is used to obtain the voltage at the positive and negative ends of the LED light string in the LED light source, and detect the magnitude of the obtained voltage and a preset reference voltage, so that the main control chip outputs a control signal to the LED driving circuit of the LED driving power supply according to the magnitude of the obtained voltage and the preset reference voltage to turn off the LED driving circuit; The threshold control circuit is connected to the main control chip and is used to send the number of lamp beads in the LED lamp string to the main control chip according to an external instruction, so that the main control chip adjusts the preset reference voltage according to the number of lamp beads.

2. The short circuit protection control circuit according to claim 1, characterized in that: The threshold control circuit includes a communication module, which is connected to the external intelligent device and the main control chip and is used to send the number of lamp beads in the LED lamp string contained in the external instruction from the external intelligent device to the main control chip.

3. The short circuit protection control circuit according to claim 2, characterized in that: The communication module includes an NFC chip.

4. The short circuit protection control circuit according to claim 1, characterized in that: The detection protection circuit includes a resistor voltage divider circuit and a comparison circuit, wherein the input end of the resistor voltage divider circuit is connected to the LED light source, and the input end of the comparison circuit is connected to the output end of the resistor voltage divider circuit, and is used to compare whether the output voltage of the resistor voltage divider circuit is greater than a preset reference voltage, and when the output voltage is greater than the preset reference voltage, the main control chip turns off the LED drive circuit.

5. The short circuit protection control circuit according to claim 4, characterized in that: The resistor voltage divider circuit includes a first resistor, a third resistor and a fourth resistor, wherein one end of the first resistor is connected to the positive electrode of the LED light string in the LED light source, and the other end thereof is connected to the negative electrode of the LED light string and one end of the third resistor, the other end of the third resistor is connected to one end of the fourth resistor and the comparison circuit, and the other end of the fourth resistor is grounded.

6. The short circuit protection control circuit according to claim 4, characterized in that: The comparison circuit comprises a first operational amplifier, an inverting input terminal of the first operational amplifier is connected to the output terminal of the resistance voltage divider circuit, and a non-inverting input terminal and an output terminal of the first operational amplifier are both connected to the main control chip.

7. The short circuit protection control circuit according to claim 6, characterized in that: The comparison circuit also includes an RC filter circuit, which includes a first capacitor and a fifth resistor, one end of the fifth resistor is connected to the in-phase input terminal of the first operational amplifier and one end of the first capacitor, the other end of the fifth resistor is connected to the main control chip, and the other end of the first capacitor is grounded.

8. A short circuit protection control circuit, applied to LED driving power supply, characterized in that: The short circuit protection control circuit comprises: A detection protection circuit is connected to the LED light source, and is used to obtain the voltage at the positive and negative ends of the LED light string in the LED light source, and detect the magnitude of the obtained voltage and a preset reference voltage; MCU, connected to the detection protection circuit and the main control chip of the LED driving power supply, used for providing a preset reference voltage, and sending a control instruction to the main control chip according to the magnitude of the acquired voltage and the preset reference voltage, so that the main control chip turns off the LED driving circuit of the LED driving power supply; The threshold control circuit is connected to the MCU and is used to send the number of lamp beads in the LED lamp string to the MCU according to an external instruction, so that the MCU adjusts the preset reference voltage according to the number of lamp beads.

9. An LED driving power supply, characterized in that: It comprises an LED driving circuit, a main control chip and a short circuit protection control circuit as claimed in any one of claims 1 to 8, wherein: The LED driving circuit is connected between the power input terminal and the LED light source, and is used to adjust the current input to the LED light source and shut off the current input to the LED light source according to the input control signal. The LED light source includes at least one LED light string. The main control chip is connected to the LED driving circuit and is used to output a control signal to the LED driving circuit to control the operation of the LED driving circuit; The short-circuit protection control circuit is connected to the LED light string and the main control chip, and is used to send the number of lamp beads in the LED light string to the main control chip according to an external instruction, so that the main control chip adjusts the preset reference voltage provided according to the number of lamp beads, and obtains the voltage across the positive and negative poles of the LED light string, detects the size of the obtained voltage and the preset reference voltage, so that the main control chip outputs a control signal to the LED drive circuit according to the size of the obtained voltage and the preset reference voltage to turn off the LED drive circuit; or, it is used to adjust the preset reference voltage according to the number of lamp beads in the LED light string in the external instruction, and obtains the voltage across the positive and negative poles of the LED light string, detects the size of the obtained voltage and the preset reference voltage, and sends a control instruction to the main control chip according to the size of the obtained voltage and the preset reference voltage, so that the main control chip turns off the LED drive circuit.

10. A lamp, characterized in that: Includes the LED driving power supply as described in claim 9.

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