TWI825667B - Power supply device - Google Patents

Abstract

A power supply device includes a bridge rectifier, a first capacitor, a transformer, a power switch element, an output stage circuit, a feedback circuit, a voltage divider circuit, and an MCU (Microcontroller Unit). The bridge rectifier generates a rectified voltage according to a first input voltage and a second input voltage. The transformer includes a main coil, a secondary coil, and an auxiliary coil. The main coil receives the rectified voltage. The output stage circuit is coupled to the secondary coil, and is configured to generate an output voltage. The feedback circuit is coupled to the auxiliary coil, and is configured to generate a feedback supply voltage. The voltage divider circuit generates a divided voltage according to the feedback supply voltage. If the divided voltage is kept higher than or equal to a threshold voltage for a predetermined time, the MCU will be automatically disabled for OVP (Over Voltage Protection).

Description

power supply

The present invention relates to a power supply, and in particular to a power supply that can avoid unexpected shutdown.

In a traditional power supply, if a momentary high-voltage noise occurs at the output end, it may accidentally trigger the Over Voltage Protection (OVP) mechanism, causing the power supply to shut down unexpectedly. In view of this, it is necessary to propose a new solution to overcome the difficulties faced by previous technologies.

In a preferred embodiment, the present invention proposes a power supply that includes: a bridge rectifier that generates a rectified potential based on a first input potential and a second input potential; a first capacitor that stores the rectified potential; A transformer includes a main coil, a secondary coil, and an auxiliary coil, wherein the transformer has a built-in magnetizing inductor, and the main coil is used to receive the rectified potential; a power switch selectively selects based on a clock potential The main coil is coupled to a ground potential; an output stage circuit is coupled to the secondary coil and generates an output potential; a feedback circuit is coupled to the auxiliary coil and generates a feedback supply potential; A voltage dividing circuit generates a divided voltage potential according to the feedback supply potential; and a microcontroller is powered by the feedback supply potential and generates the clock potential, wherein if the divided voltage potential If the voltage remains above or equal to a critical potential for a predetermined time, the microcontroller will be automatically disabled for over-voltage protection.

In some embodiments, the bridge rectifier includes: a first diode having an anode and a cathode, wherein the anode of the first diode is coupled to a first input node to receive the first input potential, and the cathode of the first diode is coupled to a first node to output the rectified potential; a second diode has an anode and a cathode, wherein the second diode The anode is coupled to a second input node to receive the second input potential, and the cathode of the second diode is coupled to the first node; a third diode has an anode and a cathode , wherein the anode of the third diode is coupled to the ground potential, and the cathode of the third diode is coupled to the first input node; and a fourth diode having an anode and a cathode, wherein the anode of the fourth diode is coupled to the ground potential, and the cathode of the fourth diode is coupled to the second input node; wherein the first capacitor has a first One terminal and a second terminal, the first terminal of the first capacitor is coupled to the first node, and the second terminal of the first capacitor is coupled to the ground potential.

In some embodiments, the main coil has a first end and a second end, the first end of the main coil is coupled to the first node to receive the rectified potential, and the second end of the main coil is coupled to a second node, the exciting inductor has a first end and a second end, the first end of the exciting inductor is coupled to the first node, and the second end of the exciting inductor The terminal is coupled to the second node, the secondary coil has a first terminal and a second terminal, the first terminal of the secondary coil is coupled to a third node, and the second terminal of the secondary coil is Coupled to a common node, the auxiliary coil has a first end and a second end, the first end of the auxiliary coil is coupled to a fourth node, and the second end of the auxiliary coil is coupled to to this ground potential.

In some embodiments, the power switch includes: a transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the transistor is used to receive the clock potential, the The first terminal of the transistor is coupled to the ground potential, and the second terminal of the transistor is coupled to the second node.

In some embodiments, the output stage circuit includes: a fifth diode having an anode and a cathode, wherein the anode of the fifth diode is coupled to the third node, and the fifth diode The cathode of the pole body is coupled to an output node to output the output potential; and a second capacitor has a first terminal and a second terminal, wherein the first terminal of the second capacitor is coupled to the output node, and the second terminal of the second capacitor is coupled to the common node.

In some embodiments, the feedback circuit includes: a sixth diode having an anode and a cathode, wherein the anode of the sixth diode is coupled to the fourth node, and the sixth second The cathode of the pole body is coupled to a supply node to output the feedback supply potential; and a third capacitor has a first terminal and a second terminal, wherein the first terminal of the third capacitor is coupled to the supply node, and the second terminal of the third capacitor is coupled to the ground potential.

In some embodiments, the voltage dividing circuit includes: a first resistor having a first terminal and a second terminal, wherein the first terminal of the first resistor is coupled to the supply node to receive the feedback supply potential, and the second terminal of the first resistor is coupled to a fifth node to output the divided voltage potential; and a second resistor having a first terminal and a second terminal , wherein the first terminal of the second resistor is coupled to the fifth node, and the second terminal of the second resistor is coupled to the ground potential.

In some embodiments, the microcontroller includes: a sampling circuit that samples the first input potential and the second input potential to generate a time domain signal; a fast Fourier transform circuit that converts the time domain signal into A frequency domain signal; a control circuit that monitors the divided voltage potential, wherein if the divided voltage potential remains higher than or equal to the critical potential for the predetermined time, the control circuit will output one of the high logic levels Control potential; and a comparator that compares the control potential with a reference potential to selectively adjust the feedback supply potential; wherein the predetermined time is determined based on the frequency domain signal.

In some embodiments, the comparator has a positive input terminal, a negative input terminal, and an output terminal, wherein the positive input terminal of the comparator is used to receive the reference potential, and the negative output terminal of the comparator is for receiving the control potential, and the output terminal of the comparator is coupled to the supply node.

In some embodiments, the predetermined time is equal to twice the reciprocal of the operating frequencies of the first input potential and the second input potential.

In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are listed below and described in detail with reference to the accompanying drawings.

Certain words are used in the specification and patent claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and the patent application do not use differences in names as a way to distinguish components, but differences in functions of components as a criterion for distinction. The words "include" and "include" mentioned throughout the specification and the scope of the patent application are open-ended terms, and therefore should be interpreted as "include but not limited to." The term "approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem and achieve the basic technical effect within a certain error range. In addition, the word "coupling" in this specification includes any direct and indirect electrical connection means. Therefore, if a first device is coupled to a second device, it means that the first device can be directly electrically connected to the second device, or indirectly electrically connected to the second device via other devices or connections. Two devices.

Figure 1 is a schematic diagram of a power supply 100 according to an embodiment of the present invention. For example, the power supply 100 can be applied to a desktop computer, a notebook computer, or an all-in-one computer. As shown in Figure 1, the power supply 100 includes: a bridge rectifier 110, a first capacitor C1, a transformer 120, a power switch 130, an output stage circuit 140, a feedback circuit 150, a voltage dividing circuit 160, and a microcontroller 170. It should be noted that, although not shown in FIG. 1 , the power supply 100 may further include other components, such as a voltage regulator or/and a negative feedback circuit.

The bridge rectifier 110 can generate the rectified potential VR according to a first input potential VIN1 and a second input potential VIN2. Both the first input potential VIN1 and the second input potential VIN2 can come from an external input power supply, wherein an AC voltage with any frequency and any amplitude can be formed between the first input potential VIN1 and the second input potential VIN2. For example, the frequency of the AC voltage can be about 50Hz or 60Hz, and the root mean square value of the AC voltage can be about 90V to 264V, but it is not limited thereto. The first capacitor C1 can be used to store the rectified potential VR. The transformer 120 includes a primary coil 121, a secondary coil 122, and an auxiliary coil 123. The transformer 120 may have a built-in magnetizing inductor LM. The primary coil 121 , the auxiliary coil 123 , and the exciting inductor LM may be located on the same side of the transformer 120 , while the secondary coil 122 may be located on the opposite side of the transformer 120 . The primary coil 121 can receive the rectified potential VR, and in response to the rectified potential VR, the secondary coil 122 and the auxiliary coil 123 can generate respective induced potentials. The power switch 130 can selectively couple the main coil 121 to a ground potential VSS according to a clock potential VA. For example, if the clock potential VA is a high logic level (ie, logic “1”), the power switch 130 may couple the main coil 121 to the ground potential VSS (ie, the power switch 130 may be approximately short-circuit path); on the contrary, if the clock potential VA is a low logic level (ie, logic “0”), the power switch 130 will not couple the main coil 121 to the ground potential VSS (ie, the power switch 130 130 can be approximated by an open path). The output stage circuit 140 is coupled to the secondary coil 122 and can generate an output potential VOUT. For example, the output potential VOUT may be a DC potential, and its potential level may be from 18V to 22V, but is not limited thereto. The feedback circuit 150 is coupled to the auxiliary coil 123 and can generate a feedback supply potential VF. The voltage dividing circuit 160 can generate a divided voltage potential VD according to the feedback supply potential VF. For example, the divided voltage potential VD may be equal to a specific percentage of the feedback supply potential VF. The microcontroller 170 is powered by the feedback supply potential VF and can generate the aforementioned clock potential VA. In addition, the microcontroller 170 can further monitor the divided voltage potential VD of the voltage dividing circuit 160 . If the divided voltage potential VD remains higher than or equal to a critical potential VTH for a predetermined time TD, the microcontroller 170 will be automatically disabled (Disabled) to perform over-voltage protection (Over Voltage Protection) of the power supply 100 ,OVP). Otherwise, the microcontroller 170 will be in the enabled state (Enabled). Under this design, even if there is a momentary high voltage noise, it will not trigger the overvoltage protection mechanism because the duration is less than the predetermined time TD. Since the probability of unexpected shutdown of the power supply 100 is greatly reduced, the present invention can effectively improve the conversion efficiency and stability of the power supply 100 .

The following embodiments will introduce the detailed structure and operation of the power supply 100 . It must be understood that these drawings and descriptions are only examples and are not intended to limit the scope of the invention.

Figure 2 is a schematic diagram of a power supply 200 according to an embodiment of the present invention. In the embodiment of FIG. 2, the power supply 200 has a first input node NIN1, a second input node NIN2, and an output node NOUT, and includes a bridge rectifier 210, a first capacitor C1, and a transformer 220 , a power switch 230, an output stage circuit 240, a feedback circuit 250, a voltage dividing circuit 260, and a microcontroller 270. The first input node NIN1 and the second input node NIN2 of the power supply 200 can respectively receive a first input potential VIN1 and a second input potential VIN2 from an external input power supply. The output node NOUT of the power supply 200 can output an output potential VOUT to an electronic device (not shown).

The bridge rectifier 210 includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. The first diode D1 has an anode and a cathode, wherein the anode of the first diode D1 is coupled to the first input node NIN1, and the cathode of the first diode D1 is coupled to a first node N1 To output the rectified potential VR. The second diode D2 has an anode and a cathode, wherein the anode of the second diode D2 is coupled to the second input node NIN2, and the cathode of the second diode D2 is coupled to the first node N1. The third diode D3 has an anode and a cathode, wherein the anode of the third diode D3 is coupled to a ground potential VSS, and the cathode of the third diode D3 is coupled to the first input node NIN1. The fourth diode D4 has an anode and a cathode, wherein the anode of the fourth diode D4 is coupled to the ground potential VSS, and the cathode of the fourth diode D4 is coupled to the second input node NIN2.

The first capacitor C1 has a first terminal and a second terminal, wherein the first terminal of the first capacitor C1 is coupled to the first node N1 to receive and store the rectified potential VR, and the second terminal of the first capacitor C1 is coupled to ground potential VSS.

The transformer 220 includes a primary coil 221, a secondary coil 222, and an auxiliary coil 223, wherein the transformer 220 may have a built-in magnetizing inductor LM. The exciting inductor LM may be an inherent component produced when the transformer 220 is manufactured, and is not an external independent component. The main coil 221, the auxiliary coil 223, and the exciting inductor LM can be located on the same side of the transformer 220 (for example, the primary side), while the secondary coil 222 can be located on the opposite side of the transformer 220 (for example, the secondary side). can be isolated from the primary side). The main coil 221 has a first end and a second end, wherein the first end of the main coil 221 is coupled to the first node N1 to receive the rectified potential VR, and the second end of the main coil 221 is coupled to a first node N1. Two nodes N2. The exciting inductor LM has a first end and a second end, wherein the first end of the exciting inductor LM is coupled to the first node N1, and the second end of the exciting inductor LM is coupled to the second node N2 . The secondary coil 222 has a first end and a second end, wherein the first end of the secondary coil 222 is coupled to a third node N3, and the second end of the secondary coil 222 is coupled to a common node NCM. For example, the common node NCM can be regarded as another ground potential, which can be the same as or different from the aforementioned ground potential VSS. The auxiliary coil 223 has a first end and a second end, wherein the first end of the auxiliary coil 223 is coupled to a fourth node N4, and the second end of the auxiliary coil 223 is coupled to the ground potential VSS.

The power switch 230 includes a transistor M1. For example, the transistor M1 may be an N-type MOSFET. The transistor M1 has a control terminal (for example: a gate), a first terminal (for example: a source), and a second terminal (for example: a drain), wherein the control terminal of the transistor M1 is used for Receiving a clock potential VA, the first terminal of the transistor M1 is coupled to the ground potential VSS, and the second terminal of the transistor M1 is coupled to the second node N2. For example, the clock potential VA can be maintained at a fixed potential when the power supply 200 is initialized, and can provide a periodic clock waveform after the power supply 200 enters the normal use stage.

The output stage circuit 240 includes a fifth diode D5 and a second capacitor C2. The fifth diode D5 has an anode and a cathode, wherein the anode of the fifth diode D5 is coupled to the third node N3, and the cathode of the fifth diode D5 is coupled to the output node NOUT. The second capacitor C2 has a first terminal and a second terminal, wherein the first terminal of the second capacitor C2 is coupled to the output node NOUT, and the second terminal of the second capacitor C2 is coupled to the common node NCM.

The feedback circuit 250 includes a sixth diode D6 and a third capacitor C3. The sixth diode D6 has an anode and a cathode, wherein the anode of the sixth diode D6 is coupled to the fourth node N4, and the cathode of the sixth diode D6 is coupled to a supply node NS to output A feedback supply potential VF is provided to the microcontroller 270 . The third capacitor C3 has a first terminal and a second terminal, wherein the first terminal of the third capacitor C3 is coupled to the supply node NS, and the second terminal of the third capacitor C3 is coupled to the ground potential VSS.

The voltage dividing circuit 260 includes a first resistor R1 and a second resistor R2. The first resistor R1 has a first terminal and a second terminal, wherein the first terminal of the first resistor R1 is coupled to the supply node NS to receive the feedback supply potential VF, and the second terminal of the first resistor R1 The terminal is coupled to a fifth node N5 to output a divided voltage potential VD to the microcontroller 270 . The second resistor R2 has a first terminal and a second terminal, wherein the first terminal of the second resistor R2 is coupled to the fifth node N5, and the second terminal of the second resistor R2 is coupled to the ground. Potential VSS.

The microcontroller 270 includes a sampling circuit 272, a Fast Fourier Transform (FFT) circuit 274, a control circuit 276, and a comparator 278. The sampling circuit 272 may sample the first input potential VIN1 and the second input potential VIN2 to generate a time domain (Time Domain) signal ST. The fast Fourier transform circuit 274 can convert the time domain signal ST into a frequency domain (Frequency Domain) signal SF. Figure 3 is a waveform diagram showing the time domain signal ST and the frequency domain signal SF according to an embodiment of the present invention. As shown in Figure 3, the frequency domain signal SF can be used to indicate one of the operating frequencies FIN of the first input potential VIN1 and the second input potential VIN2.

The control circuit 276 is coupled to the fifth node N5 and continuously monitors the divided voltage potential VD. If the divided voltage potential VD remains higher than or equal to a critical potential VTH for a predetermined time TD, the control circuit 276 will output a control potential VC with a high logic level; otherwise, the control circuit 276 will output a low logic level. Accurate control potential VC. The critical potential VTH and the predetermined time TD can be internal parameters of the control circuit 276, which can be adjusted according to different needs. For example, the predetermined time TD can be determined based on the frequency domain signal SF of the fast Fourier transform circuit 274 . The comparator 278 can compare the control potential VC and a reference potential VREF to selectively adjust the feedback supply potential VF. In some embodiments, the comparator 278 has a positive input terminal, a negative input terminal, and an output terminal, wherein the positive input terminal of the comparator 278 is used to receive the reference potential VREF, and the negative output terminal of the comparator 278 is used to receive the reference potential VREF. Upon receiving the control potential VC, the output terminal of the comparator 278 is coupled to the supply node NS.

FIG. 4 shows a waveform diagram of the divided voltage potential VD and the control potential VC according to an embodiment of the present invention. Initially, since the divided voltage potential VD is lower than the critical potential VTH, the control potential VC can be maintained at a low logic level. At this time, the microcontroller 270 is enabled and can be powered by the feedback supply potential VF at the supply node NS. Then, because the divided voltage potential VD rises and remains higher than or equal to the critical potential VTH for a predetermined time TD, the control circuit 276 switches the control potential VC from a low logic level to a high logic level. At this time, the control potential VC is higher than the reference potential VREF, so the output end of the comparator 278 will quickly pull down the feedback supply potential VF at the supply node NS, causing the microcontroller 270 to be disabled. That is, the over-voltage protection mechanism of the power supply 200 will be triggered only under conditions that last for a long time. On the contrary, even if a momentary high voltage noise occurs, the overvoltage protection mechanism cannot be activated because the duration is too short, so the probability of unexpected shutdown of the power supply 200 can be effectively reduced.

In some embodiments, component parameters of the power supply 200 may be as follows. The inductance value of the magnetizing inductor LM can be between 324μH and 396μH, preferably 360μH. The capacitance value of the first capacitor C1 can be between 96 μF and 144 μF, preferably 120 μF. The capacitance value of the second capacitor C2 can be between 544μF and 816μF, preferably 680μF. The capacitance value of the third capacitor C3 can be between 4.23μF and 5.17μF, preferably 4.7μF. The resistance value of the first resistor R1 can be between 9.9KΩ and 10.1KΩ, preferably 10KΩ. The resistance value of the second resistor R2 can be between 9.9KΩ and 10.1KΩ, preferably 10KΩ. The turns ratio of the primary coil 221 to the secondary coil 222 can be between 1 and 100, preferably 20. The turns ratio of the main coil 221 to the auxiliary coil 223 can be between 1 and 10, preferably 6.67. The reference potential VREF can be 14V. The switching frequency of the clock potential VA can be greater than or equal to 150kHz. The predetermined time TD may be equal to 2 times the reciprocal of the operating frequency FIN of the first input potential VIN1 and the second input potential VIN2 (that is, TD=2/FIN). The above parameter range is obtained based on the results of multiple experiments, which helps to minimize the possibility of unexpected shutdown of the power supply 200 while maximizing the conversion efficiency of the power supply 200 itself.

The present invention proposes a novel power supply. According to the actual measurement results, the power supply using the above design can prevent the over-voltage protection mechanism from being accidentally triggered due to the occurrence of instantaneous high-voltage noise, so it is very suitable for use in various electronic devices.

It is worth noting that the above-mentioned potential, current, resistance value, inductance value, capacitance value, and other component parameters are not limiting conditions of the present invention. Designers can adjust these settings according to different needs. The power supply of the present invention is not limited to the state shown in Figures 1-4. The present invention may only include any one or multiple features of any one or multiple embodiments of Figures 1-4. In other words, not all features shown in the figures need to be implemented in the power supply of the present invention at the same time. Although the embodiment of the present invention uses a metal oxide semi-field effect transistor as an example, the present invention is not limited thereto. Those skilled in the art can use other types of transistors, such as junction field effect transistors or fins. type field effect transistor, etc., without affecting the effect of the present invention.

The ordinal numbers in this specification and the scope of the patent application, such as "first", "second", "third", etc., have no sequential relationship with each other. They are only used to distinguish two items with the same Different components with names.

Although the present invention is disclosed above in terms of preferred embodiments, they are not intended to limit the scope of the present invention. Anyone skilled in the art can make slight changes and modifications without departing from the spirit and scope of the present invention. Therefore, The protection scope of the present invention shall be determined by the appended patent application scope.

100,200:Power supply 110,210: Bridge rectifier 120,220:Transformer 121,221: Main coil 122,222: Secondary coil 123,223: Auxiliary coil 130,230:Power switcher 140,240: Output stage circuit 150,250: Feedback circuit 160,260: voltage divider circuit 170,270:Microcontroller 272: Sampling circuit 274: Fast Fourier transform circuit 276:Control circuit 278: Comparator C1: first capacitor C2: Second capacitor C3: The third capacitor D1: first diode D2: Second diode D3: The third diode D4: The fourth diode D5: The fifth diode D6: The sixth diode FIN: operating frequency LM: Magnetizing inductor M1: Transistor N1: first node N2: second node N3: The third node N4: fourth node N5: fifth node NCM: common node NIN1: first input node NIN2: second input node NOUT: output node NS: supply node R1: first resistor R2: second resistor SF: frequency domain signal ST: time domain signal TD: established time VA: clock potential VC: control potential VD: voltage dividing potential VF: Feedback supply potential VIN1: first input potential VIN2: second input potential VOUT: output potential VR: rectifier potential VREF: reference potential VSS: ground potential VTH: critical potential

Figure 1 is a schematic diagram of a power supply according to an embodiment of the present invention. Figure 2 is a schematic diagram of a power supply according to an embodiment of the present invention. Figure 3 is a waveform diagram showing a time domain signal and a frequency domain signal according to an embodiment of the present invention. Figure 4 is a waveform diagram showing the divided voltage potential and the control potential according to an embodiment of the present invention.

100:Power supply 110: Bridge rectifier 120:Transformer 121: Main coil 122: Secondary coil 123: Auxiliary coil 130:Power switcher 140:Output stage circuit 150:Feedback circuit 160: Voltage dividing circuit 170:Microcontroller C1: first capacitor LM: Magnetizing inductor TD: established time VA: clock potential VD: voltage dividing potential VF: Feedback supply potential VIN1: first input potential VIN2: second input potential VOUT: output potential VR: rectifier potential VSS: ground potential VTH: critical potential

Claims (9)

A power supply includes: a bridge rectifier, which generates a rectified potential according to a first input potential and a second input potential; a first capacitor, which stores the rectified potential; a transformer, which includes a main coil and a secondary coil , and an auxiliary coil, wherein the transformer has a built-in magnetizing inductor, and the main coil is used to receive the rectification potential; a power switch selectively couples the main coil to a ground according to a clock potential. potential; an output stage circuit is coupled to the auxiliary coil and generates an output potential; a feedback circuit is coupled to the auxiliary coil and generates a feedback supply potential; a voltage dividing circuit is based on the feedback supply potential to generate a divided voltage potential; and a microcontroller that is powered by the feedback supply potential and generates the clock potential, wherein if the divided voltage potential remains higher than or equal to a critical potential for After a predetermined time, the microcontroller will be automatically disabled for over-voltage protection; the predetermined time is equal to twice the reciprocal of the operating frequency of the first input potential and the second input potential. The power supply of claim 1, wherein the bridge rectifier includes: a first diode having an anode and a cathode, wherein the anode of the first diode is coupled to a first input node. receiving the first input potential, and the cathode of the first diode is coupled to a first node to output the rectified potential; a second diode having an anode and a cathode, wherein the anode of the second diode is coupled to a second input node to receive the second input potential, and the a cathode is coupled to the first node; a third diode having an anode and a cathode, wherein the anode of the third diode is coupled to the ground potential, and the the cathode is coupled to the first input node; and a fourth diode having an anode and a cathode, wherein the anode of the fourth diode is coupled to the ground potential, and the fourth diode the cathode of the pole body is coupled to the second input node; wherein the first capacitor has a first terminal and a second terminal, and the first terminal of the first capacitor is coupled to the first node, The second terminal of the first capacitor is coupled to the ground potential. The power supply of claim 2, wherein the main coil has a first end and a second end, the first end of the main coil is coupled to the first node to receive the rectified potential, and the main coil has a first end and a second end. The second terminal is coupled to a second node, the magnetizing inductor has a first terminal and a second terminal, the first terminal of the magnetizing inductor is coupled to the first node, and the magnetizing inductor The second end is coupled to the second node, the secondary coil has a first end and a second end, the first end of the secondary coil is coupled to a third node, and the secondary coil has a first end and a second end. The second end is coupled to a common node, the auxiliary coil has a first end and a second end, the first end of the auxiliary coil is coupled to a fourth node, and the second end of the auxiliary coil The terminals are coupled to this ground potential. The power supply of claim 3, wherein the power switch includes: A transistor has a control terminal, a first terminal, and a second terminal, wherein the control terminal of the transistor is used to receive the clock potential, and the first terminal of the transistor is coupled to the ground potential, and the second terminal of the transistor is coupled to the second node. The power supply of claim 3, wherein the output stage circuit includes: a fifth diode having an anode and a cathode, wherein the anode of the fifth diode is coupled to the third node, and The cathode of the fifth diode is coupled to an output node to output the output potential; and a second capacitor has a first terminal and a second terminal, wherein the first terminal of the second capacitor is is coupled to the output node, and the second terminal of the second capacitor is coupled to the common node. The power supply of claim 3, wherein the feedback circuit includes: a sixth diode having an anode and a cathode, wherein the anode of the sixth diode is coupled to the fourth node, and The cathode of the sixth diode is coupled to a supply node to output the feedback supply potential; and a third capacitor having a first terminal and a second terminal, wherein the first terminal of the third capacitor A terminal is coupled to the supply node, and the second terminal of the third capacitor is coupled to the ground potential. The power supply of claim 6, wherein the voltage dividing circuit includes: a first resistor having a first terminal and a second terminal, wherein the first terminal of the first resistor is coupled to the a supply node to receive the feedback supply potential, and the second end of the first resistor is coupled to a fifth node to output the divided voltage potential; and a second resistor having a first terminal and a second terminal, wherein the first terminal of the second resistor is coupled to the fifth node, and the second terminal of the second resistor is coupled to connected to this ground potential. The power supply of claim 6, wherein the microcontroller includes: a sampling circuit that samples the first input potential and the second input potential to generate a time domain signal; a fast Fourier transform circuit that converts the time domain signal The domain signal is converted into a frequency domain signal; a control circuit monitors the divided voltage potential, wherein if the divided voltage potential remains higher than or equal to the critical potential for the predetermined time, the control circuit will output a high logic A control potential of a level; and a comparator that compares the control potential with a reference potential to selectively adjust the feedback supply potential; wherein the predetermined time is determined based on the frequency domain signal. The power supply of claim 8, wherein the comparator has a positive input terminal, a negative input terminal, and an output terminal, wherein the positive input terminal of the comparator is used to receive the reference potential, and the comparator has a positive input terminal. The negative output terminal is used to receive the control potential, and the output terminal of the comparator is coupled to the supply node.

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