TWI826072B - Power supply device with high output stability - Google Patents

Abstract

A power supply device with high output stability includes a bridge rectifier, a transformer, a power switch element, an output stage circuit, a feedback compensation circuit, and a detection and control circuit. The transformer includes a main coil and a secondary coil. The power switch element selectively couples the main coil to a ground voltage according to a clock voltage. The output stage circuit generates an output voltage. The feedback compensation circuit generates a divided voltage and a capacitive voltage according to the output voltage. The detection and control circuit generates the clock voltage according to the capacitive voltage. The detection and control circuit also monitors the divided voltage. If the divided voltage is lower than or equal to a threshold voltage, the detection and control circuit will increase and update the capacitive voltage of the feedback compensation circuit.

Description

High output stability power supply

The present invention relates to a power supply, and in particular to a power supply with high output stability.

The power supply is an indispensable component in the notebook computer field. However, if the output stability of the power supply is insufficient, it will easily cause the overall operating performance of the related notebook computer to decline. 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 with high output stability, including: a bridge rectifier that generates a rectified potential based on a first input potential and a second input potential; a transformer including a main A coil and a secondary coil, wherein the primary coil is used to receive the rectified potential, and the secondary coil is used to output an induced potential; a power switch selectively couples the primary coil to the A ground potential; an output stage circuit, which generates an output potential based on the induced potential; a feedback compensation circuit, which generates a divided voltage potential and a capacitor potential based on the output potential; and a detection and control circuit, based on The capacitor potential is used to generate the clock potential; the detection and control circuit further monitors the divided voltage potential, and if the divided voltage potential is lower than or equal to a critical potential, the detection and control circuit will increase and updating the capacitor potential of the feedback compensation circuit.

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 FIG. 1 , the power supply 100 includes: a bridge rectifier 110 , a transformer 120 , a power switch 130 , an output stage circuit 140 , a feedback compensation circuit 150 , and a detection and control circuit 160 . 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 a rectified potential VR according to a first input potential VIN1 and a second input potential VIN2, wherein one of the first input potential VIN1 and the second input potential VIN2 can have any frequency and any amplitude. AC voltage. For example, the frequency of the AC voltage can be about 50Hz or 60Hz, and the root mean square (RMS) of the AC voltage can be about 90V to 264V, but it is not limited thereto. The transformer 120 includes a primary coil 121 and a secondary coil 122. The primary coil 121 may be located on one side of the transformer 120, and the secondary coil 122 may be located on the opposite side of the transformer 120. The primary coil 121 can be used to receive the rectified potential VR, and in response to the rectified potential VR, the secondary coil 122 can be used to output an induced potential VS. The power switch 130 can selectively couple the main coil 121 to a ground potential VSS (eg, 0V) 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 can couple the main coil 121 to the ground potential VSS (ie, the power switch 130 can be approximately a short-circuit path); conversely, 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 may approximate an open path). The output stage circuit 140 can generate an output potential VOUT according to the induced potential VS. For example, the output potential VOUT may be a DC potential, and its potential level may be between 18V and 20V, but is not limited thereto. The feedback compensation circuit 150 can generate a divided voltage potential VD and a capacitor potential VT according to the output potential VOUT. The detection and control circuit 160 can generate the clock potential VA according to the capacitor potential VT. The detection and control circuit 160 can further monitor the divided voltage potential VD. If the divided voltage potential VD is lower than or equal to a critical potential VTH, the detection and control circuit 160 will increase and update the capacitor potential VT of the feedback compensation circuit 150 . Under the design of the present invention, the detection and control circuit 160 can determine whether there is an error value in the capacitor potential VT of the feedback compensation circuit 150 based on the divided voltage potential VD. If so, the detection and control circuit 160 will appropriately adjust the capacitor potential VT of the feedback compensation circuit 150, thereby effectively improving the output 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 circuit 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 transformer 220, and a power switch 230. , an output stage circuit 240, a feedback compensation circuit 250, and a detection and control circuit 260. The first input node NIN1 and the second input node NIN2 of the power supply 200 can be used to receive a first input potential VIN1 and a second input potential VIN2 respectively. The output node NOUT of the power supply 200 can be used to output an output potential VOUT.

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 transformer 220 includes a primary coil 221 and a secondary coil 222, wherein the transformer 220 may further 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 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, which can be connected to the primary side). isolated). In detail, 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 Connected to a second node 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 to output an induced potential VS, 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 power switch 230 includes a first transistor M1. For example, the first transistor M1 may be an N-type Metal-Oxide-Semiconductor Field-Effect Transistor (NMOSFET). The first 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 first transistor M1 The terminal is used to receive a clock potential VA, the first terminal of the first transistor M1 is coupled to the ground potential VSS, and the second terminal of the first transistor M1 is coupled to the second node N2. The power switch 230 may further have a built-in parasitic capacitor CP. In detail, the parasitic capacitor CP has a first end and a second end, wherein the first end of the parasitic capacitor CP is coupled to the second node N2, and the second end of the parasitic capacitor CP is coupled to the ground potential VSS. . It must be understood that the total parasitic capacitance between the first terminal and the second terminal of the first transistor M1 can be simulated as the aforementioned parasitic capacitor CP, which is not an external independent component.

The output stage circuit 240 includes a fifth diode D5 and a first capacitor C1. 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 to receive the induced potential VS, and the cathode of the fifth diode D5 is coupled to the output Node NOUT. 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 output node NOUT, and the second terminal of the first capacitor C1 is coupled to the common node NCM.

In some embodiments, the feedback compensation circuit 250 includes a linear optocoupler 252, a voltage regulator 254, a second capacitor C2, a third capacitor C3, 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 output node NOUT to receive the output potential VOUT, and the second terminal of the first resistor R1 is Coupled to a fourth node N4 to output a divided voltage potential VD. 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 fourth node N4, and the second terminal of the second resistor R2 is coupled to the common node N4. Node NCM. The second capacitor C2 has a first terminal and a second terminal, wherein the first terminal of the second capacitor C2 is coupled to a fifth node N5, and the second terminal of the second capacitor C2 is coupled to the fourth node. N4.

In some embodiments, linear optocoupler 252 is implemented with a PC817 electronic component. The linear optical coupler 252 includes a light-emitting diode DL and a bicarrier junction transistor Q1 (for example, NPN type). The light-emitting diode DL has an anode and a cathode, wherein the anode of the light-emitting diode DL is coupled to the output node NOUT, and the cathode of the light-emitting diode DL is coupled to the fifth node N5. The bipolar junction transistor Q1 has a collector and an emitter. The collector of the bipolar junction transistor Q1 is used to output a feedback potential VF to the detection and control circuit 260, and the bipolar junction transistor Q1 The emitter of junction transistor Q1 is coupled to a sixth node N6.

In some embodiments, voltage regulator 254 is implemented with a TL431 electronic component. The voltage regulator 254 has an anode, a cathode, and a reference terminal, wherein the anode of the voltage regulator 254 is coupled to the common node NCM, the cathode of the voltage regulator 254 is coupled to the fifth node N5, and the voltage regulator 254 has an anode, a cathode, and a reference terminal. The reference terminal of 254 is coupled to the fourth node N4.

In addition, 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 sixth node N6 to provide a capacitance potential VT, and the second terminal of the third capacitor C3 is coupled to ground potential VSS. It must be noted that the feedback potential VF is related to the capacitor potential VT. Therefore, the detection and control circuit 260 can also obtain relevant information about the capacitor potential VT by analyzing the feedback potential VF.

The detection and control circuit 260 includes a microcontroller unit (MCU) 262, an error amplifier (Error Amplifier) 266, a second transistor M2, a third transistor M3, a fourth capacitor C4, and a third resistor R3. For example, the second transistor M2 and the third transistor M3 may each be an N-type MOSFET.

The microcontroller 262 can receive the divided voltage potential VD and the feedback potential VF, and can generate the clock potential VA and an inverted clock potential VB according to the feedback potential VF (or the capacitor potential VT), wherein the clock potential VA and the inverted clock potential VB may have complementary logic levels. In addition, the microcontroller 262 monitors the divided voltage potential VD more continuously, wherein the microcontroller 262 stores a lookup table 264 . If the divided voltage potential VD is lower than or equal to a critical potential VTH (for example: 2.5V), the microcontroller 262 will query the lookup table 264 according to the divided voltage potential VD to generate a corresponding target potential VG. In some embodiments, the lookup table 264 of the microcontroller 262 may be as follows: Divided voltage potential VD Corresponding target potential VG Target duty cycle of clock potential VA 2.5V 3.1V 30% 2.3V 3.3V 38% 2.1V 3.5V 46% 1.9V 3.7V 54% 1.7V 3.9V 62% 1.5V 4.1V 70% 1.3V 4.3V 78% 1.1V 4.5V 86% Table 1: Comparison table of microcontrollers

For example, if the divided voltage potential VD becomes low, the target potential VG generated by the microcontroller 262 will subsequently become high, thereby increasing the target duty cycle of the clock potential VA. In some embodiments, the sum of the divided voltage potential VD and the corresponding target potential VG can be a constant value (for example: 5.6V), but it is not limited to this.

The second transistor M2 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 second transistor M2 The terminal is used to receive the inverted clock potential VB, the first terminal of the second transistor M2 is coupled to a seventh node N7, and the second terminal of the second transistor M2 is coupled to the second node N2. The third resistor R3 has a first terminal and a second terminal, wherein the first terminal of the third resistor R3 is coupled to an eighth node N8, and the second terminal of the third resistor R3 is coupled to The seventh node N7. The fourth capacitor C4 has a first terminal and a second terminal, wherein the first terminal of the fourth capacitor C4 is coupled to the eighth node N8, and the second terminal of the fourth capacitor C4 is coupled to the ground potential VSS.

The error amplifier 266 has a positive input terminal, a negative input terminal, and an output terminal. The positive input terminal of the error amplifier 266 is used to receive the target potential VG, and the negative input terminal of the error amplifier 266 is used to receive the capacitor potential VT. The output terminal of the error amplifier 266 is used to output a control potential VC. The third transistor M3 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 third transistor M3 The terminal is used to receive the control potential VC, the first terminal of the third transistor M3 is coupled to the sixth node N6, and the second terminal of the third transistor M3 is coupled to the eighth node N8.

Figure 3 shows a potential waveform diagram of the power supply 200 according to an embodiment of the present invention, in which the horizontal axis represents time and the vertical axis represents each potential level. Please refer to Figures 2 and 3 together to understand the operating principle of the power supply 200.

When the clock potential VA has a high logic level, the first transistor M1 will be enabled, and the second transistor M2 will be disabled. At this time, electromagnetic energy will be stored in the magnetizing inductor LM of the transformer 220, and the parasitic capacitor CP of the power switch 230 will be charged.

On the contrary, when the pulse potential VA has a low logic level, the first transistor M1 will be disabled and the second transistor M2 will be enabled. At this time, the first capacitor C1 is indirectly charged by the magnetizing inductor LM, and the fourth capacitor C4 is indirectly charged by the parasitic capacitor CP. It should be noted that the fourth capacitor C4 can approximately store an average potential, which is equal to the potential V8 at the eighth node N8.

Figure 4 shows a potential waveform diagram of the power supply 200 according to an embodiment of the present invention, in which the horizontal axis represents time and the vertical axis represents each potential level. Please refer to Figures 2 and 4 together to understand the operating principle of the power supply 200.

If the divided voltage potential VD is lower than or equal to the critical potential VTH, it means that the potential level of the output potential VOUT is too low. This may be caused by the third capacitor C3 deteriorating and its capacitance potential VT being insufficient. As mentioned above, the microcontroller 262 will generate the target potential VG according to the divided voltage potential VD. At this time, the error amplifier 266 compares the target potential VG with the capacitor potential VT to generate the control potential VC. It must be noted that if the potential difference between the target potential VG and the capacitor potential VT becomes larger, the control potential VC will gradually increase. The third transistor M3 can transfer the energy stored in the fourth capacitor C4 to the third capacitor C3 according to the control potential VC, thereby compensating the capacitance potential VT of the third capacitor C3. In some embodiments, the third transistor M3 can operate in a triode mode (which can also be called a "Linear Region"). That is, if the control potential VC becomes higher, the third transistor M3 will be able to transmit more energy to the third capacitor C3.

According to the measurement results in Figure 4, if the capacitor potential VT is raised from a lower level VL1 to a higher level VL2, the microcontroller 262 will increase the duty cycle (Duty Cycle) of the clock potential VA, so that The output potential VOUT of the power supply 200 increases accordingly. Therefore, even if the third capacitor C3 is aged due to high temperature, the output potential VOUT of the power supply 200 can still return to an acceptable range.

The present invention proposes a novel power supply that can automatically adjust its internal circuit according to real-time output conditions. According to the actual measurement results, using the power supply designed as mentioned above can greatly improve the overall output stability, so it is very suitable for use in various 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 1-43. 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 130,230:Power switcher 140,240: Output stage circuit 150,250: Feedback compensation circuit 160,260: Detection and control circuit 252:Linear Optocoupler 254:Voltage regulator 262:Microcontroller 264: Comparison table 266: Error amplifier C1: first capacitor C2: Second capacitor C3: The third capacitor C4: The fourth capacitor CP: parasitic capacitor D1: first diode D2: Second diode D3: The third diode D4: The fourth diode D5: The fifth diode DL: light emitting diode LM: Magnetizing inductor M1: the first transistor M2: Second transistor M3: The third transistor M4: The fourth transistor N1: first node N2: second node N3: The third node N4: fourth node N5: fifth node N6: The sixth node N7: The seventh node N8: The eighth node NCM: common node NIN1: first input node NIN2: second input node NOUT: output node Q1: Bicarrier junction transistor R1: first resistor R2: second resistor R3: The third resistor V8:potential VA: clock potential VB: reverse clock potential VC: control potential VD: voltage dividing potential VF: feedback potential VG: target potential VIN1: first input potential VIN2: second input potential VL1: lower level VL2: higher level VOUT: output potential VR: rectifier potential VS: induced potential VSS: ground potential VT: capacitor 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 circuit diagram showing a power supply according to an embodiment of the present invention. Figure 3 shows a potential waveform diagram of a power supply according to an embodiment of the present invention. Figure 4 shows a potential waveform diagram of a power supply according to an embodiment of the present invention.

100:Power supply

110: Bridge rectifier

120:Transformer

121: Main coil

122: Secondary coil

130:Power switcher

140:Output stage circuit

150:Feedback compensation circuit

160: Detection and control circuit

VA: clock potential

VD: voltage dividing potential

VIN1: first input potential

VIN2: second input potential

VOUT: output potential

VR: rectifier potential

VS: induced potential

VSS: ground potential

VT: capacitor potential

VTH: critical potential

Claims (8)

A power supply with high output stability, including: a bridge rectifier, which generates a rectified potential according to a first input potential and a second input potential; a transformer, including a main coil and a secondary coil, wherein the main coil is used to receive the rectified potential, and the secondary coil is used to output an induced potential; a power switch selectively couples the main coil to a ground potential according to a clock potential; an output stage circuit is used according to The induced potential generates an output potential; a feedback compensation circuit generates a divided voltage potential and a capacitor potential based on the output potential; and a detection and control circuit generates the clock potential based on the capacitor potential; The detection and control circuit further monitors the divided voltage potential, and if the divided voltage potential is lower than or equal to a critical potential, the detection and control circuit will increase and update the capacitor of the feedback compensation circuit. potential; wherein the detection and control circuit includes: a microcontroller, which receives the divided voltage potential and a feedback potential from the feedback compensation circuit, and generates the clock potential and an inverse voltage according to the feedback potential. Phase clock potential, wherein the microcontroller further stores a lookup table; if the divided voltage potential is lower than or equal to the critical potential, the microcontroller will query the lookup table based on the divided voltage potential to Generate a target 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 to receive the first input potential, and the first diode The cathode is coupled to a first node to output the rectified potential; a second diode has 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 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 fourth diode The anode is coupled to the ground potential, and the cathode of the fourth diode is coupled to the second input node. The power supply of claim 2, wherein the transformer further builds a magnetizing inductor, the main coil has a first end and a second end, and the first end of the main coil is coupled to the first node To receive the rectified potential, the second end of the main coil is coupled to a second node, the exciting inductor has a first end and a second end, and the first end of the exciting inductor is coupled to The first node, the second end of the exciting inductor are 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 The third node is used to output the induced potential, and the second end of the secondary coil is coupled to a common node. The power supply of claim 3, wherein the power switch includes: A first transistor has a control end, a first end, and a second end, wherein the control end of the first transistor is used to receive the clock potential, and the first end of the first transistor The terminal is coupled to the ground potential, and the second terminal of the first transistor is coupled to the second node; wherein the power switch further has a built-in parasitic capacitor, the parasitic capacitor has a first terminal and a second terminal, the first terminal of the parasitic capacitor is coupled to the second node, and the second terminal of the parasitic capacitor is coupled to the ground potential. 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 to receive the induced potential, and the cathode of the fifth diode is coupled to an output node to output the output potential; and a first capacitor having a first terminal and a second terminal, wherein the first capacitor The first terminal is coupled to the output node, and the second terminal of the first capacitor is coupled to the common node. The power supply of claim 5, wherein the feedback compensation 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 An output node receives the output potential, and the second end of the first resistor is coupled to a fourth node to output the divided voltage potential; a second resistor has a first end and a second terminals, wherein the first terminal of the second resistor is coupled to the fourth node, and the second terminal of the second resistor is coupled to the common node; a second capacitor having a first terminal and a second terminal, wherein the first terminal of the second capacitor is coupled to a fifth node, and the second terminal of the second capacitor is coupled to the The fourth node; a voltage regulator having an anode, a cathode, and a reference terminal, wherein the anode of the voltage regulator is coupled to the common node, and the cathode of the voltage regulator is coupled to the third node. five nodes, and the reference terminal of the voltage regulator is coupled to the fourth node; a linear optical coupler including a light-emitting diode and a bicarrier junction transistor, wherein the light-emitting diode has An anode and a cathode, the anode of the light-emitting diode is coupled to the output node, the cathode of the light-emitting diode is coupled to the fifth node, the bicarrier junction transistor has a and an emitter, the collector of the bipolar junction transistor is used to output the feedback potential to the detection and control circuit, and the emitter of the bipolar junction transistor is coupled to a sixth node; and a third capacitor having a first terminal and a second terminal, wherein the first terminal of the third capacitor is coupled to the sixth node to provide the capacitance potential, and the third capacitor The second terminal of the three capacitors is coupled to the ground potential; wherein the feedback potential is associated with the capacitor potential. The power supply of claim 6, wherein the detection and control circuit further includes: a second transistor having a control terminal, a first terminal, and a second terminal, wherein the control of the second transistor The terminal is used to receive the inverted clock potential, the first terminal of the second transistor is coupled to a seventh node, and the second terminal of the second transistor is coupled to the second node ; A third resistor having a first terminal and a second terminal, wherein the first terminal of the third resistor is coupled to an eighth node, and the second terminal of the third resistor is coupled to connected to the seventh node; and a fourth capacitor having a first terminal and a second terminal, wherein the first terminal of the fourth capacitor is coupled to the eighth node, and the fourth capacitor The second terminal is coupled to the ground potential. Such as the power supply of claim 7, wherein the detection and control circuit further includes: an error amplifier having a positive input terminal, a negative input terminal, and an output terminal, wherein the positive input terminal of the error amplifier is In receiving the target potential, the negative input terminal of the error amplifier is used to receive the capacitor potential, and the output terminal of the error amplifier is used to output a control potential; and a third transistor has a control terminal, a first end, and a second end, wherein the control end of the third transistor is used to receive the control potential, the first end of the third transistor is coupled to the sixth node, and the The second terminal of the third transistor is coupled to the eighth node.

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