Power supply over-temperature protection circuit, power supply and electronic equipment

Abstract

The utility model relates to a power supply over-temperature protection circuit, a power supply and electronic equipment. The circuit comprises a voltage sampling unit, a first comparison unit, a reference voltage generation unit, a second comparison unit, a temperature sensing unit and a reference current generation unit, the voltage sampling unit is connected with the power input circuit and generates sampling voltage; the temperature sensing unit is used for generating sensing voltage according to temperature; the first comparison unit is connected with the voltage sampling unit and outputs a first comparison result; the reference voltage generation unit is connected with the first comparison unit and generates reference voltage according to the first comparison result; the second comparison unit is connected with the reference voltage generation unit and the temperature sensing unit and used for outputting a second comparison result; the reference current generation unit is connected with the second comparison unit and the power supply output circuit and is used for generating first reference current or second reference current. According to the utility model, the over-temperature protection point can be reduced when the input voltage is low, so that the reliability of the power supply is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply, and more specifically to a power supply over-temperature protection circuit, a power supply and an electronic device. Background Art

[0002] At present, with the increasing diversification of electronic product usage scenarios, the design process of electronic products, especially power supply design, has high requirements for power supply reliability. Power supplies designed with narrow voltage (120V-264V) input voltage have the advantages of small size and high power density. However, if the power grid is unstable and the input voltage is reduced, the power supply will be damaged due to its small size, insufficient heat dissipation, and increased device temperature. Therefore, when designing a power supply, over-temperature protection of the power supply will be considered. In the actual power supply circuit, when the input voltage is lower than the rated input voltage, the temperature rise rate will accelerate. In the currently commonly used over-temperature protection circuit, it is usually not affected by the input voltage, so that the over-temperature protection circuit cannot work effectively and timely, and cannot effectively guarantee the reliability of the power supply. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a power supply over-temperature protection circuit, a power supply and an electronic device in view of the above-mentioned technical defects of the prior art.

[0004] The technical solution adopted by the utility model to solve the technical problem is: constructing a power supply over-temperature protection circuit, including: a voltage sampling unit, a first comparison unit, a reference voltage generating unit, a second comparison unit, a temperature sensing unit and a reference current generating unit;

[0005] The voltage sampling unit is used to connect to the power input circuit and to generate a sampling voltage according to the power input;

[0006] The temperature sensing unit is used to generate an induced voltage according to the temperature;

[0007] The first comparison unit is connected to the voltage sampling unit, and is used to receive the sampled voltage and output a first comparison result;

[0008] The reference voltage generating unit is connected to the first comparing unit and is used to generate a reference voltage according to the first comparing result;

[0009] The second comparison unit is connected to the reference voltage generation unit and the temperature sensing unit, and is used to receive the reference voltage and the sensing voltage and output a second comparison result;

[0010] The reference current generating unit is connected to the second comparing unit and the power supply output circuit, and is used to generate a first reference current or a second reference current according to the second comparison result; wherein the power supply output circuit is used to adjust the output according to the first reference current or the second reference current.

[0011] Preferably, in the power supply over-temperature protection circuit described in the utility model, the first comparison unit includes a first operational amplifier, a first resistor, a second resistor and a third resistor;

[0012] A first input terminal of the first operational amplifier is connected to the voltage sampling unit, a second input terminal of the first operational amplifier is connected to a first terminal of the first resistor, a first terminal of the second resistor and a first terminal of the third resistor, an output terminal of the first operational amplifier is connected to the reference voltage generating unit and a second terminal of the third resistor, a second terminal of the first resistor is connected to a reference voltage input, and a second terminal of the second resistor is grounded.

[0013] Preferably, in the power supply over-temperature protection circuit described in the utility model, the reference voltage generating unit includes a switch circuit, a fourth resistor, a fifth resistor and a sixth resistor;

[0014] The control end of the switch circuit is connected to the output end of the first comparison unit, the first end of the switch circuit is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the first end of the fifth resistor, the first end of the sixth resistor and the first input end of the second comparison unit, the second end of the fifth resistor is connected to a reference voltage input, and the second end of the switch circuit and the second end of the sixth resistor are grounded.

[0015] Preferably, in the power supply over-temperature protection circuit of the utility model, the switch circuit includes a switch tube, a seventh resistor and an eighth resistor;

[0016] The control end of the switch tube is connected to the first end of the seventh resistor and the first end of the eighth resistor, the first end of the switch tube is connected to the first end of the fourth resistor, the second end of the seventh resistor is connected to the output end of the first comparison unit, and the second end of the eighth resistor and the second end of the switch tube are grounded.

[0017] Preferably, in the power supply over-temperature protection circuit described in the utility model, the second comparison unit includes a second operational amplifier and a tenth resistor;

[0018] A first input terminal of the second operational amplifier is connected to a first end of the tenth resistor, a second end of the fourth resistor, a first end of the fifth resistor, and a first end of the sixth resistor, a second input terminal of the second operational amplifier is connected to the temperature sensing unit, and an output terminal of the second operational amplifier is connected to a second end of the tenth resistor and the reference current generating unit.

[0019] Preferably, in the power supply over-temperature protection circuit of the utility model, the temperature sensing unit includes a thermistor and a ninth resistor;

[0020] The first end of the thermistor is connected to a reference voltage input, and the second end of the thermistor is connected to the first end of the ninth resistor and the second input end of the second comparing unit.

[0021] Preferably, in the power supply over-temperature protection circuit described in the utility model, the reference current generating unit includes a diode, an eleventh resistor, a twelfth resistor and a thirteenth resistor;

[0022] The anode of the diode is connected to the first end of the eleventh resistor, and the cathode of the diode is connected to the output end of the second comparing unit;

[0023] The second end of the eleventh resistor is connected to the power supply output end, the first end of the twelfth resistor and the first end of the thirteenth resistor, the second end of the twelfth resistor is connected to a reference current input, and the second end of the thirteenth resistor is grounded.

[0024] Preferably, in the power supply over-temperature protection circuit described in the utility model, the voltage sampling unit includes a first voltage dividing circuit and a second voltage dividing circuit;

[0025] A first end of the first voltage divider circuit is connected to the power input circuit, a second end of the first voltage divider circuit is connected to a first end of the second voltage divider circuit and a first input end of the first comparison unit, and a second end of the second voltage divider circuit is grounded.

[0026] The utility model also constructs a power supply, comprising: a power input circuit and a power output circuit, and a power over-temperature protection circuit as described in any one of the above items.

[0027] The utility model also constructs an electronic device, comprising the power supply as described above.

[0028] A power supply over-temperature protection circuit, power supply and electronic equipment implementing the utility model have the following beneficial effects: the over-temperature protection point can be lowered when the input voltage is low, so as to improve the reliability of the power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0030] Figure 1 It is a structural schematic diagram of a power supply over-temperature protection circuit of the utility model;

[0031] Figure 2This is a circuit schematic diagram of a first embodiment of a power supply over-temperature protection circuit of the utility model;

[0032] Figure 3 The utility model is a partial circuit schematic diagram of an embodiment of a power supply. DETAILED DESCRIPTION

[0033] In order to have a clearer understanding of the technical features, purposes and effects of the present utility model, the specific implementation methods of the present utility model are now described in detail with reference to the accompanying drawings.

[0034] like Figure 1As shown, in a first embodiment of a power supply over-temperature protection circuit of the utility model, the circuit includes: a voltage sampling unit 110, a first comparison unit 120, a reference voltage generating unit 130, a second comparison unit 150, a temperature sensing unit 140 and a reference current generating unit 160; the voltage sampling unit 110 is used to connect to the power input circuit 210 in the power supply, and is used to generate a sampling voltage according to the power input; the temperature sensing unit 140 is used to generate an induced voltage according to the temperature; the first comparison unit 120 is connected to the voltage sampling unit 110, and is used to receive the sampling voltage and output a first comparison result; the reference voltage generating unit 130 is connected to the first comparison unit 120, and is used to generate a reference voltage according to the first comparison result; the second comparison unit 150 is connected to the reference voltage generating unit 130 and the temperature sensing unit 140, and is used to receive the reference voltage and the induced voltage and output a second comparison result; the reference current generating unit 160 is connected to the second comparison unit 150 and the power output circuit 220 in the power supply, and is used to generate a first reference current or a second reference current according to the second comparison result; wherein the power output circuit 220 is used to control the output of the power output circuit 220 according to the first reference current or the second reference current. Specifically, the power input of the power input circuit 210 of the power supply is sampled by the voltage sampling unit 110 to obtain a corresponding sampled voltage. The first comparison unit 120 compares the sampled voltage with a preset threshold voltage and outputs a corresponding comparison result, i.e., a first comparison result. The reference voltage generation unit 130 outputs a corresponding voltage according to the first comparison result. When the power input of the power input circuit 210 is different, the voltage sampling unit 110 obtains different sampled voltages, and the first comparison unit 120 can output different first comparison results according to the different magnitudes of the sampled voltages. In one embodiment, when the sampled voltage is greater than or equal to the preset threshold value, the first comparison unit 120 outputs a first level, and when the sampled voltage is less than the preset threshold value, the first comparison unit 120 outputs a second level. The reference voltage generation unit 130 generates a first reference voltage when receiving the first level, and generates a second reference voltage when receiving the second level. The second comparison unit 150 compares the first reference voltage or the second reference voltage with the induced voltage generated by the temperature sensing unit 140 to obtain a corresponding comparison result, i.e., a second comparison result. The temperature sensing unit 140 is used to generate different induced voltages at different temperatures. The second comparison unit 150 compares the first reference voltage or the second reference voltage with the induced voltage when receiving the first reference voltage or the second reference voltage and outputs a corresponding second comparison result. The second comparison result can be a different level, namely a third level or a fourth level. The reference current generation unit 160 generates a first reference current when receiving the third level, and generates a second reference current when receiving the fourth level. The power output circuit 220 adjusts the output of the power output circuit 220 according to the first reference current or the second reference current.In this embodiment, the first comparison unit 120 determines the sampling voltage, i.e., the power input, and drives the reference voltage generation unit 130 to generate different reference voltages, so that the temperature sensing unit 140 can drive the second comparison unit 150 to change the output result at different temperatures, and then the reference current generation unit 160 outputs a change, i.e., outputs the first reference current or the second reference current. For example, when the sampling voltage is lower than the preset threshold, the reference voltage generation unit 130 is driven to generate a lower reference voltage, and the temperature sensing unit 140 can trigger the second comparison unit 150 to change the output result when the temperature is lower. At the same time, through this protection circuit, different reference currents can be obtained when the power temperature is normal or too high, so that the power output circuit 220 performs corresponding actions to confirm whether it is necessary to reduce the output to achieve the purpose of reducing the power temperature.

[0035] Optional, such as Figure 2 As shown, the first comparison unit 120 includes a first operational amplifier, a first resistor, a second resistor and a third resistor; the first input end of the first operational amplifier is connected to the voltage sampling unit 110, the second input end of the first operational amplifier is connected to the first end of the first resistor, the first end of the second resistor and the first end of the third resistor, the output end of the first operational amplifier is connected to the reference voltage generation unit 130 and the second end of the third resistor, the second end of the first resistor is connected to a reference voltage input, and the second end of the second resistor is grounded. Specifically, the first operational amplifier includes an operational amplifier chip U1-A, the first resistor includes a resistor R6, the second resistor includes a resistor R7, and the third resistor includes a resistor R8. Resistors R6 and R7 are connected in series to form a voltage divider circuit, which divides the input voltage VREF at the reference voltage input end, and inputs a reference signal at the second input end of the operational amplifier chip U1-A through the joint action of resistor R8. The operational amplifier chip U1-A compares the sampled voltage output by the voltage sampling unit 110 with the reference signal. When the sampled voltage is higher than or equal to the reference signal, the output end of the operational amplifier chip U1-A outputs a low level, and the reference voltage generation unit 130 receives the low level to generate a first reference voltage. When the sampling voltage is lower than the reference signal, the output terminal of the operational amplifier chip U1 -A outputs a high level, and the reference voltage generating unit 130 receives the high level to generate a second reference voltage.

[0036] Optionally, the reference voltage generating unit 130 includes a switch circuit, a fourth resistor, a fifth resistor and a sixth resistor; the control end of the switch circuit is connected to the output end of the first comparison unit 120, the first end of the switch circuit is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the first end of the fifth resistor, the first end of the sixth resistor and the first input end of the second comparison unit 150, the second end of the fifth resistor is connected to a reference voltage input, and the second end of the switch circuit and the second end of the sixth resistor are grounded. Specifically, in the reference voltage generating unit 130, the fourth resistor includes a resistor R12, the fifth resistor includes a resistor R9, and the sixth resistor includes a resistor R13. The switch circuit is turned off when the output of the first comparison unit 120 is a low level, at which time the reference voltage input is divided by the resistor R9 and the resistor R13 to obtain a first reference voltage input to the first input end of the second comparison unit 150, and the switch circuit is turned off when the output of the first comparison unit 120 is a high level, at which time the reference voltage input is divided by the voltage divider circuit composed of the resistor R9, the resistor R12 and the resistor R13 to obtain a second reference voltage input to the first input end of the second comparison unit 150.

[0037] Further, the switch circuit includes a switch tube, a seventh resistor and an eighth resistor; the control end of the switch tube is connected to the first end of the seventh resistor and the first end of the eighth resistor, the first end of the switch tube is connected to the first end of the fourth resistor, the second end of the seventh resistor is connected to the output end of the first comparison unit 120, and the second end of the eighth resistor and the second end of the switch tube are grounded. Specifically, in the switch circuit, the switch tube includes a transistor Q1, the seventh resistor includes a resistor R10, and the eighth resistor includes a resistor R11. The level output by the output end of the first comparison unit 120 forms a driving level at the base of the transistor Q1 through the voltage division of the resistor R10 and the resistor R11. When the driving level is high, the transistor Q1 is turned on, that is, the switch circuit is in the on state, and when the driving level is low, the transistor Q1 is turned off, that is, the switch circuit is in the off state.

[0038] Optionally, the second comparison unit 150 includes a second operational amplifier and a tenth resistor; the first input end of the second operational amplifier is connected to the first end of the tenth resistor, the second end of the fourth resistor, the first end of the fifth resistor and the first end of the sixth resistor, the second input end of the second operational amplifier is connected to the temperature sensing unit 140, and the output end of the second operational amplifier is connected to the second end of the tenth resistor and the reference current generating unit 160. Specifically, in the second comparison unit 150, the second operational amplifier includes an operational amplifier chip U1-B, the tenth resistor includes a resistor R14, and the second input end of the operational amplifier chip U1-B receives the induced voltage. When the first end of the resistor R9 provides the first reference voltage to the first input end of the operational amplifier chip U1-B, the operational amplifier chip U1-B compares the induced voltage with the first reference voltage, and when the induced voltage is higher than the first reference voltage, the output end of the operational amplifier chip U1-B outputs a low level, and when the induced voltage is less than or equal to the first reference voltage, the output end of the operational amplifier chip U1-B outputs a high level. When the first end of the resistor R9 provides the second reference voltage to the first input end of the operational amplifier chip U1-B, the operational amplifier chip U1-B compares the induced voltage with the second reference voltage. When the induced voltage is higher than the second reference voltage, the output end of the operational amplifier chip U1-B outputs a low level. When the induced voltage is less than or equal to the second reference voltage, the output end of the operational amplifier chip U1-B outputs a high level. By designing the size of the first reference voltage and the second reference, the operational amplifier chip U1-B can perform result conversion at different temperatures.

[0039] Optionally, the temperature sensing unit 140 includes a thermistor and a ninth resistor; the first end of the thermistor is connected to a reference voltage input, and the second end of the thermistor is connected to the first end of the ninth resistor and the second input end of the second comparison unit 150. Specifically, the temperature sensing unit 140 includes a thermistor NTC and a resistor R15, i.e., a ninth resistor. The thermistor NTC and the resistor R15 are connected in series and generate an induced voltage at the series connection point and input the second input end of the second comparison unit 150. The thermistor NTC has different resistance values ​​at different temperatures. When the power supply temperature is low, the resistance value of the thermistor NTC is high, and the reference voltage VREF of the reference voltage input forms a lower induced voltage at the second input end of the second comparison unit 150. When it is lower than the first reference voltage or the second reference voltage, the output end of the second comparison unit 150 outputs a high level, and at this time, the reference current generating unit 160 can generate the first reference current accordingly. When the power supply temperature is high, the resistance of the thermistor NTC becomes smaller, and the reference voltage VREF of the reference voltage input forms a higher induced voltage at the second input terminal of the second comparison unit 150. When it is higher than or equal to the first reference voltage or the second reference voltage, the output terminal of the second comparison unit 150 outputs a low level. At this time, the reference current generation unit 160 can generate a second reference current accordingly.

[0040] Optionally, the reference current generating unit 160 includes a diode, an eleventh resistor, a twelfth resistor and a thirteenth resistor; the anode of the diode is connected to the first end of the eleventh resistor, and the cathode of the diode is connected to the output end of the second comparison unit 150; the second end of the eleventh resistor is connected to the power supply output end 222, the first end of the twelfth resistor and the first end of the thirteenth resistor, the second end of the twelfth resistor is connected to a reference current input, and the second end of the thirteenth resistor is grounded. Specifically, the reference current generating unit 160 includes a diode D1, a resistor R16 (corresponding to the eleventh resistor), a resistor R17 (corresponding to the twelfth resistor) and a resistor R18 (corresponding to the thirteenth resistor). A high level is output at the output end of the second comparison unit 150, the diode D1 is turned off, and the reference current IREF of the reference current input generates a first reference current at the output end of the reference current generating unit 160 through the voltage division of the resistors R17 and R18. The output terminal of the second comparison unit 150 outputs a low level, the diode D1 is turned on, and the reference current IREF of the reference current input is divided by the resistors R16, R17 and R18 to generate a second reference current at the output terminal of the reference current generation unit 160. Figure 3 As shown, in the power output circuit 220, the output current of the reference current generating unit 160 and the power output terminal 222 can be compared through the current feedback control loop, and then the comparison result is generated to control the working state of the power change unit, the purpose of which is that when the actual output current is too large, the output current of the power output terminal 222 can be reduced through the power conversion unit 221. Through this protection circuit, different reference currents can be obtained when the power temperature is normal or too high, so that the power conversion unit 221 performs corresponding actions to achieve the purpose of quickly reducing the output of the power output terminal 222 and lowering the power temperature. The current feedback control loop in the power output circuit 220 can include operation U2 and its peripheral circuits, which are used to compare the power output of the power output terminal 222 and the reference current. The operation of the power conversion unit 221 can adopt the current control process commonly used in current power supplies.

[0041] Optionally, the voltage sampling unit 110 includes a first voltage divider circuit and a second voltage divider circuit; the first end of the first voltage divider circuit is connected to the power input circuit 210, the second end of the first voltage divider circuit is connected to the first end of the second voltage divider circuit and the first input end of the first comparison unit 120, and the second end of the second voltage divider circuit is grounded. Specifically, in the voltage sampling unit 110, the first voltage divider circuit is composed of a plurality of resistors connected in series and / or in parallel. For example, a first voltage divider circuit is formed by connecting resistors R1, R2, R3, and R4 in series. The second voltage divider circuit may also be composed of a plurality of resistors connected in series and / or in parallel, or may be a single resistor. For example, resistor R5 constitutes a second voltage divider circuit connected in series with the first voltage divider circuit and generates a sampling voltage at the series node.

[0042] A power supply of the utility model comprises: a power input circuit 210 and a power output circuit 220, and a power over-temperature protection circuit as any one of the above. That is, in the power supply, the power supply is protected by the above power over-temperature protection circuit. The power output circuit 220 adjusts its output current according to the reference circuit output by the power over-temperature protection circuit, so that the power supply can be cooled quickly when over-temperature occurs. Figure 3 As shown, the power output circuit 220 may include a power conversion unit 221, a power output terminal 222, and a current feedback control loop. The power conversion unit 221 controls the output of the power output terminal 222 according to the output of the current feedback control loop, and the current feedback control loop generates a control signal according to the reference current generated by the power over-temperature protection circuit and the output current of the power output terminal 222. The power input circuit 210 may include a voltage change unit such as a rectifier bridge stack and a PFC circuit.

[0043] An electronic device of the utility model comprises the above power supply, that is, in the electronic device, the above power supply is arranged to supply power, so as to improve the temperature reliability of the whole electronic device.

[0044] It can be understood that the above embodiments only express the preferred implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the utility model. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the utility model, the above-mentioned technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the utility model. Therefore, all equivalent changes and modifications made to the scope of the claims of the utility model should belong to the scope covered by the claims of the utility model.

Claims

1. A power supply over-temperature protection circuit, characterized in that: include: A voltage sampling unit, a first comparing unit, a reference voltage generating unit, a second comparing unit, a temperature sensing unit and a reference current generating unit; The voltage sampling unit is used to connect to the power input circuit and to generate a sampling voltage according to the power input; The temperature sensing unit is used to generate an induced voltage according to the temperature; The first comparison unit is connected to the voltage sampling unit, and is used to receive the sampled voltage and output a first comparison result; The reference voltage generating unit is connected to the first comparing unit and is used to generate a reference voltage according to the first comparing result; The second comparison unit is connected to the reference voltage generation unit and the temperature sensing unit, and is used to receive the reference voltage and the sensing voltage and output a second comparison result; The reference current generating unit is connected to the second comparing unit and the power supply output circuit, and is used to generate a first reference current or a second reference current according to the second comparison result; wherein the power supply output circuit is used to adjust the output according to the first reference current or the second reference current.

2. The power supply over-temperature protection circuit according to claim 1, characterized in that: The first comparison unit includes a first operational amplifier, a first resistor, a second resistor and a third resistor; A first input terminal of the first operational amplifier is connected to the voltage sampling unit, a second input terminal of the first operational amplifier is connected to a first terminal of the first resistor, a first terminal of the second resistor and a first terminal of the third resistor, an output terminal of the first operational amplifier is connected to the reference voltage generating unit and a second terminal of the third resistor, a second terminal of the first resistor is connected to a reference voltage input, and a second terminal of the second resistor is grounded.

3. The power supply over-temperature protection circuit according to claim 1, characterized in that: The reference voltage generating unit includes a switch circuit, a fourth resistor, a fifth resistor and a sixth resistor; The control end of the switch circuit is connected to the output end of the first comparison unit, the first end of the switch circuit is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the first end of the fifth resistor, the first end of the sixth resistor and the first input end of the second comparison unit, the second end of the fifth resistor is connected to a reference voltage input, and the second end of the switch circuit and the second end of the sixth resistor are grounded.

4. The power supply over-temperature protection circuit according to claim 3, characterized in that: The switch circuit includes a switch tube, a seventh resistor and an eighth resistor; The control end of the switch tube is connected to the first end of the seventh resistor and the first end of the eighth resistor, the first end of the switch tube is connected to the first end of the fourth resistor, the second end of the seventh resistor is connected to the output end of the first comparison unit, and the second end of the eighth resistor and the second end of the switch tube are grounded.

5. The power supply over-temperature protection circuit according to claim 3, characterized in that: The second comparison unit includes a second operational amplifier and a tenth resistor; A first input terminal of the second operational amplifier is connected to a first end of the tenth resistor, a second end of the fourth resistor, a first end of the fifth resistor, and a first end of the sixth resistor, a second input terminal of the second operational amplifier is connected to the temperature sensing unit, and an output terminal of the second operational amplifier is connected to a second end of the tenth resistor and the reference current generating unit.

6. The power supply over-temperature protection circuit according to claim 1, characterized in that: The temperature sensing unit includes a thermistor and a ninth resistor; The first end of the thermistor is connected to a reference voltage input, and the second end of the thermistor is connected to the first end of the ninth resistor and the second input end of the second comparing unit.

7. The power supply over-temperature protection circuit according to claim 1, characterized in that: The reference current generating unit includes a diode, an eleventh resistor, a twelfth resistor and a thirteenth resistor; The anode of the diode is connected to the first end of the eleventh resistor, and the cathode of the diode is connected to the output end of the second comparing unit; The second end of the eleventh resistor is connected to the power supply output end, the first end of the twelfth resistor and the first end of the thirteenth resistor, the second end of the twelfth resistor is connected to a reference current input, and the second end of the thirteenth resistor is grounded.

8. The power supply over-temperature protection circuit according to claim 1, characterized in that: The voltage sampling unit includes a first voltage dividing circuit and a second voltage dividing circuit; A first end of the first voltage divider circuit is connected to the power input circuit, a second end of the first voltage divider circuit is connected to a first end of the second voltage divider circuit and a first input end of the first comparison unit, and a second end of the second voltage divider circuit is grounded.

9. A power supply, characterized in that: include: A power input circuit and a power output circuit, and a power over-temperature protection circuit as claimed in any one of claims 1 to 8.

10. An electronic device, characterized in that: Comprising the power supply as claimed in claim 9.

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