TWI825689B - Power supply capable of displaying efficiency - Google Patents

Abstract

A power supply capable of displaying efficiency is provided. The power supply includes a transformer, a primary side circuit and a secondary side circuit, a display unit, and a processor. The primary side circuit includes an excitation inductor. The processor receives a RMS voltage value and an average current value related to the excitation inductor, an input voltage value of an input power, and an output voltage value and an output current value from the secondary side circuit. The processor generates a compensation value based on the input voltage value, and calculates an efficiency value based on the compensation value, the RMS voltage value, the average current value, the output voltage value and the output current value. The processor controls the display unit to display information corresponding to the efficiency value.

Description

Display performance power supply

The present invention relates to a power supply, and in particular to a power supply with display performance.

Power supplies are used to provide power to various electronic devices. The performance value (or efficiency) of the power supply provided by the power supply requires the use of additional instruments to measure. However, measuring performance values through instruments requires complex pre-operations. In addition, the instrument will be affected by the environment (such as temperature and humidity) during the measurement process, resulting in poor accuracy of the performance value obtained.

The present invention provides a power supply that displays performance, can display a performance value with high accuracy, and can know the performance value of the power supply in real time.

The power supply with display performance of the present invention includes a rectifier, a transformer, a primary side circuit, a secondary side circuit, a display element and a processor. The rectifier rectifies the input power. The transformer includes a primary side winding and a secondary side winding. primary side The circuit is coupled to the primary side winding and coupled to the rectifier at the first node. The primary side circuit includes the sampling resistor and the magnetizing inductor. The sampling resistor and the primary side winding are coupled in series between the first node and the second node. The exciting inductor is coupled in parallel to the primary side winding. The secondary circuit is coupled to the secondary winding. The processor performs the following operations: receives the effective voltage value between the first node and the second node, receives the average current value of the current flowing through the exciting inductor, receives the input voltage value of the input power supply, receives the input voltage value from the secondary side circuit. Output voltage value and output current value; generate a compensation value based on the input voltage value, calculate the first power value based on the compensation value, the effective voltage value and the average current value, and calculate the second power value based on the output voltage value and the output current value; and , calculate the performance value based on the first power value and the second power value, and control the display element to display information corresponding to the performance value.

Based on the above, the embodiment of the present invention obtains the first power value by calculating the effective voltage value, the average current value and the input voltage value related to the input power supply, and obtains the third power value by calculating the output voltage value and output current value related to the output power supply. The second power value can be used to obtain and instantly display the work/output performance value of the power supply. In this way, the power supply that displays the performance can obtain the output performance value based on the various current values and voltage values corresponding to its internal circuit without adding additional instruments for measuring the performance value, so as to accurately and real-timely Display performance value.

In order to make the above-mentioned features and advantages of the present invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings.

100, 200, 700: power supply

110, 210: Rectifier

120, 220: Transformer

130, 230: Primary side circuit

131, 231: Primary side voltage sensor

132, 232: Primary side current sensor

140, 240: Secondary side circuit

150, 250: display components

160, 260: Processor

241: Secondary side current sensor

270: Input voltage sampling circuit

280: Output voltage sampling circuit

310:Controller

a1, b1, c1, d1, e1, f1, g1, a2, b2, c2, d2, e2, f2, g2: Display signal

CIN: stabilizing capacitor

CO: output capacitor

CX1, CX2: energy storage capacitor

DIN, DX: unidirectional diode

DIV, DIV1, DIV2: divider

DO: output diode

EF: effectiveness value

EF(%): Percentage of effectiveness value

GND, GND1, GND2: ground terminal

IL: average current value

IO: output current value

K: compensation value

LM: Magnetizing inductor

MUL1, MUL2, MUL3: multiplier

N1, N2, N3: winding

ND1, ND2: nodes

NP: primary side winding

NS: secondary side winding

PM1, PM2: power value

Q1: Power switch

RO1, RO2: resistor

RL: Sampling resistor

RX: energy resistor

SC: control signal

SD1, SD2: seven-segment display

SD1C, SD2C: display data

VCC1, VCC2: power supply

VI: input voltage value

VIN: input power

VL: effective voltage value

VO: output voltage value

VOUT: output power

VR: Rectified power supply

VREF: time-varying reference voltage value

FIG. 1 is a block diagram of a power supply according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a power supply according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of a processor according to the embodiment of FIG. 2 of the present invention.

FIG. 4 is a schematic diagram of a controller according to the embodiment of FIG. 3 of the present invention.

5A and 5B are schematic diagrams of a display according to the embodiment of FIG. 2 of the present invention.

FIG. 6 is a circuit diagram of a display according to the embodiment of FIG. 5A of the present invention.

FIG. 7 is a schematic diagram of a power supply according to an embodiment of the present invention.

Some embodiments of the present invention will be described in detail with reference to the accompanying drawings. The component symbols cited in the following description will be regarded as the same or similar components when the same component symbols appear in different drawings. These embodiments are only part of the present invention and do not disclose all possible implementations of the present invention. Rather, these embodiments are only examples within the scope of the patent application of the invention.

Please refer to FIG. 1 , which is a block diagram of a power supply according to an embodiment of the present invention. In this embodiment, the power supply 100 includes a rectifier 110, a transformer 120, a primary side circuit 130, a secondary side circuit 140, and a display element. 150 and processor 160. Rectifier 110 rectifies input power VIN to produce rectified power VR. The transformer 120 is coupled to the primary side circuit 130 and the secondary side circuit 140, and the transformer 120 performs a voltage transformation operation on the rectified power supply VR. Transformer 120 includes a primary side winding NP and a secondary side winding NS. In this embodiment, the primary side circuit 130 includes a sampling resistor RL, a magnetizing inductor LM, and a power switch Q1. The sampling resistor RL and the primary side winding NP are coupled in series between the node ND1 and the node ND2. The exciting inductor LM is coupled in parallel to the primary side winding NP. The first terminal of the power switch Q1 is coupled to the node ND2. The second terminal of the power switch Q1 is coupled to the ground terminal GND1. The control terminal of the power switch Q1 receives the control signal SC. The secondary circuit 140 is coupled to the secondary winding NS. Secondary side circuit 140 provides output power to the load.

In this embodiment, the processor 160 is further coupled to the display element 150 . The processor 160 receives the effective voltage value VL between the node ND1 and the node ND2, the average current value IL of the current flowing through the exciting inductor LM, and the input voltage value VI of the input power supply VIN. In this embodiment, the effective voltage value VL is provided by the primary side voltage sensor 131, for example. The average current value IL is provided, for example, by the primary side current sensor 132 . Therefore, the processor 160 generates the compensation value K according to the input voltage value VI, and calculates the first power value PM1 (ie, the input power value) according to the compensation value K, the effective voltage value VL and the average current value IL. In addition, the processor 160 also receives the output voltage value VO and the output current value IO of the secondary side circuit 140, and calculates the second power value PM2 (ie, the output power value) based on the output voltage value VO and the output current value IO. The processor 160 calculates the performance value EF based on the first power value PM1 and the second power value PM2. The performance value EF is associated with the performance status of the power supply 100 . besides, The processor 160 can also control the display element 150 to display a real-time message corresponding to the current performance value EF.

The display element 150 can provide a display function for a liquid crystal display (LCD), at least one light-emitting diode (LED), at least one organic light-emitting diode (OLED), etc. display device.

The processor 160 is, for example, a central processing unit (CPU), or other programmable general-purpose or special-purpose microprocessor (Microprocessor), digital signal processor (Digital Signal Processor, DSP), programmable Controllers, Application Specific Integrated Circuits (ASIC), Programmable Logic Devices (PLD) or other similar devices or combinations of these devices, which can load and execute computer programs.

It is worth mentioning here that the power supply 100 can obtain the first power value PM1 and the second power value PM2 by itself and calculate the performance value EF without using additional instruments for measurement. In this way, the present invention can avoid the inconvenience and measurement errors caused by using additional instruments, and can provide high-precision results. In addition, the display element 150 can display the performance value EF of the power supply 100 in real time. In this way, the instantaneous power output status of the power supply 100 can be known.

Please refer to FIG. 2 , which is a circuit diagram of a power supply according to an embodiment of the present invention. The power supply 200 includes a rectifier 210, a transformer 220, a primary side circuit 230, a secondary side circuit 240, a display element 250, a processor 260, Primary side voltage sensor 231, primary side current sensor 232 and input voltage sampling circuit 270.

In this embodiment, the rectifier 210 is a full-bridge rectifier. The configuration of the rectifier 210 in this embodiment is only an example. Any rectifier circuit that can rectify alternating current is within the scope of the present invention, and the configuration of the rectifier of the present invention is not limited to this embodiment.

The implementation of the transformer 220, the primary side circuit 230 and the display element 250 of this embodiment can be sufficiently taught in the embodiment of FIG. 1 and will not be described again.

In this embodiment, the primary side voltage sensor 231 is coupled to the nodes ND1 and ND2 and the processor 260 . The primary side voltage sensor 231 senses the effective voltage value VL between the node ND1 and the node ND2 and provides the effective voltage value VL to the processor 260 . The effective voltage value VL may be the root mean square voltage value located between the node ND1 and the node ND2. That is, the effective voltage value VL is the Root Mean Square (RMS) value of the voltage value connected in series between the sampling resistor RL and the exciting inductor LM. In other embodiments, the primary side voltage sensor 231 may be integrated into the primary side circuit 230 .

It should be noted that in this embodiment, the voltage value across the exciting inductor LM will exhibit a negative value at some points in time. The sampling resistor RL is provided to raise the voltage level of the effective voltage value VL. Therefore, the effective voltage value VL is not less than zero at any point in time. In this way, the sampling resistor RL can avoid distortion of the effective voltage value VL and can also reduce the error of the first power value PM1.

In this embodiment, the primary side current sensor 232 is coupled to the processor 260 . The primary side current sensor 232 is coupled in parallel to the magnetizing inductor LM. Primary side current sensor 232 is coupled to processor 260 . The primary side current sensor 232 senses the average current value IL of the current flowing through the magnetizing inductor LM and provides the average current value IL to the processor 260 . In other embodiments, the primary side current sensor 232 may be integrated into the primary side circuit 230 .

In this embodiment, the input voltage sampling circuit 270 is coupled between the input power supply VIN and the processor 260 . The input voltage sampling circuit 270 samples the input power supply VIN to obtain the input voltage value VI, and provides the input voltage value VI to the processor 260 .

In this embodiment, the input voltage sampling circuit 270 may include a unidirectional diode DIN and a voltage stabilizing capacitor CIN. The anode of the one-way diode DIN is coupled to the input power supply VIN. The cathode of the one-way diode DIN is coupled to the first terminal of the voltage stabilizing capacitor CIN and the processor 260 . The second terminal of the voltage stabilizing capacitor CIN is coupled to the ground terminal GND1. The input voltage sampling circuit 270 will instantly sample the input voltage value VI of the input power supply VIN via the one-way diode DIN and the voltage stabilizing capacitor CIN. Therefore, the input voltage value VI is an instant voltage value.

Compared with the embodiment of FIG. 1 , the transformer 220 further includes windings N1 ~ N2 and energy storage capacitors CX1 ~ CX2. Winding N1 is electrically isolated from the primary side winding NP. Winding N1 is coupled in parallel to energy storage capacitor CX1. Winding N1 is coupled to processor 260 . The winding N1 senses the electric energy of the primary side winding NP to generate corresponding electric energy. The energy storage capacitor CX1 filters the electric energy generated by the winding N1 and generates the power supply VCC1 to the processor 260 . Therefore, through the transforming operation of the primary side winding NP and the winding N1, the processor 260 can obtain the power supply VCC1. Power supply VCC1 is associated with input power supply VIN. When the processor 260 receives the power supply VCC1, it indicates that the primary side circuit 230 is operating normally. Therefore, the processor 260 can normally calculate the first power value PM1.

Similarly, winding N2 is electrically isolated from the secondary side winding NS. Winding N2 is coupled in parallel to energy storage capacitor CX2. Winding N2 is coupled to processor 260 . Winding N2 senses the electric energy of secondary side winding NS and generates corresponding electric energy. The energy storage capacitor CX2 filters the electric energy generated by the winding N2 and then generates the power supply VCC2 to the processor 260 . Therefore, through the transforming operation of the secondary side winding NS and the winding N2, the processor 260 can obtain the power supply VCC2. Power supply VCC2 is associated with output power supply VOUT. When the processor 260 receives the power supply VCC2, it means that the power supply 200 can normally provide the output power VOUT. Therefore, the processor 260 can normally calculate the second power value PM2.

In this embodiment, the transformer 220 further includes a winding N3. The power supply 200 further includes an output voltage sampling circuit 280 . The output voltage sampling circuit 280 is coupled between the winding N3 and the processor 260 . Winding N3 is electrically isolated from the secondary side winding NS. The output voltage sampling circuit 280 samples the output power supply VOUT. Through the transforming operation of the secondary side winding NS and the winding N3, the output voltage sampling circuit 280 obtains the output voltage value VO, and provides the output voltage value VO to the processor 260.

It is worth mentioning here that the primary side winding NP is electrically isolated from the winding N1. The secondary side winding NS is electrically isolated from the windings N2 and N3 respectively. Therefore, the power supply 200 can prevent the processor 260 from encountering electromagnetic interference or crashing during the power supply process. In addition, the electrical isolation configuration of the present invention can also protect the safety of users.

In this embodiment, the output voltage sampling circuit 280 may include a unidirectional diode DX and an energy resistor RX. The anode of the unidirectional diode DX is coupled to the first end of the winding N3. The cathode of the unidirectional diode DX is coupled to the first terminal of the energy resistor RX and the processor 260 . The second terminal of the energy resistor RX is coupled to the second terminal of the winding N3. The output voltage sampling circuit 280 obtains the output voltage value through the energy resistor RX.

In this embodiment, the secondary side circuit 240 includes an output diode DO, an output capacitor CO, and a secondary side current sensor 241 . The anode of the output diode DO is coupled to the first end of the secondary side winding NS. The cathode of the output diode DO is coupled to the output power supply VOUT and serves as the output terminal of the secondary side circuit 240 . The first terminal of the output capacitor CO is coupled to the cathode of the output diode DO. The first terminal of the output capacitor CO serves as the output terminal of the secondary side circuit 240 . The second terminal of the output capacitor CO is coupled to the secondary side current sensor 241 . The secondary current sensor 241 is coupled between the second terminal of the output capacitor CO and the second terminal of the secondary winding NS. The secondary side current sensor 241 senses the output current value IO.

In this embodiment, the secondary side current sensor 241 may include resistors RO1, RO2 and a secondary side divider DIV. The resistor RO1 is coupled between the second terminal of the output capacitor CO and the second terminal of the secondary winding NS. The second end of the secondary side winding NS is coupled to the ground terminal GND2. Resistor RO1 provides a voltage value corresponding to the output current value IO. Resistor RO2 provides a reference resistance value, that is, the resistance value of resistor RO2 itself. The resistance values of resistors RO1 and RO2 are substantially equal.

In this embodiment, the secondary side divider DIV is coupled to the resistor RO1, RO2 and processor 260. The secondary side divider DIV receives the voltage value corresponding to the output current value IO, divides the voltage value corresponding to the output current value IO by the reference resistance value to obtain the output current value IO, and provides the output current value IO to the processor 260 .

In this embodiment, the processor 260 receives the effective voltage value VL, the average current value IL, the input voltage value VI, the output voltage value VO, the output current value IO, and the power supplies VCC1 and VCC2. The processor 260 outputs a message corresponding to the performance value EF. This information can be a percentage value of the performance value and is represented by display data SD1C and SD2C.

Display element 250 includes seven-segment displays SD1, SD2. The seven-segment displays SD1 and SD2 can display Arabic numerals to respectively represent tens-digit information and single-digit information of the percentage value of the performance value. For example, the seven-segment display SD1 is used to display tens-digit information. The seven-segment display SD2 is used to display single-digit information. In other embodiments, the seven-segment displays SD1 and SD2 may display performance values in other representations.

Please refer to FIG. 2 and FIG. 3. FIG. 3 is a schematic diagram of the processor 260 according to the embodiment of FIG. 2 of the present invention. In this embodiment, the processor 260 further includes dividers DIV1, DIV2, multipliers MUL1~MUL3 and a controller 310. The dividers DIV1 and DIV2 may be circuits with division operation functions. The multipliers MUL1~MUL3 can be circuits with multiplication functions.

The divider DIV1 receives the input voltage value VI and the time-varying reference voltage value VREF. The divider DIV1 divides the input voltage value VI by the time-varying reference voltage value VREF to generate the compensation value K, as shown in the following equation (1):

In this embodiment, the time-varying reference voltage value VREF may be a parameter known within the processor 260 and may change in size over time. The time-varying reference voltage value VREF may be negatively or positively related to the input voltage value VI. In other embodiments, the compensation value K is the result of dividing the time-varying reference voltage value VREF by the input voltage value VI. It should be understood that different ways of obtaining the compensation value K will be related to the waveform of the time-varying reference voltage value VREF.

The multiplier MUL1 is coupled to the divider DIV1. The multiplier MUL1 multiplies the compensation value K, the effective voltage value VL and the average current value IL to generate the power value PM1, as shown in the following equation (2): PM 1= K × VL × IL (2).

It should be noted that since the input voltage value VI is the voltage signal sampled by the input power supply VIN, it is an AC signal whose voltage value changes with time. Therefore, the average current value IL sensed by the magnetizing inductor LM is also an AC signal. In addition, since the average current value IL is related to the power value PM1, if the AC signal is directly multiplied, accuracy will be lost. The compensation value K is a time-varying parameter and is negatively related to the average current value IL and the effective voltage value VL. Therefore, the processor 260 uses the compensation value K to compensate for the AC fluctuation of the average current value IL to improve the accuracy of the power value PM1.

Multiplier MUL2 receives the output voltage value VO and the output current value IO. The multiplier MUL2 multiplies the output voltage value VO and the output current value IO to generate the power value PM2, as shown in the following equation (3): PM 2= VO × IO (3).

It should be noted that when processor 260 receives power supplies VCC1 and VCC2 When, the divider DIV1, multipliers MUL1 and MUL2 can perform the corresponding operations. In other words, the processor 260 can start operating only when receiving the power supplies VCC1 and VCC2.

The divider DIV2 is coupled to the multipliers MUL1 and MUL2, and divides the power value PM2 by the power value PM1 to generate an efficiency value EF. The multiplier MUL3 is coupled to the divider DIV2 and multiplies the performance value EF by 100 to generate a percentage value EF(%) corresponding to the performance value.

The controller 310 is coupled to the multiplier MUL3, and converts the percentage value EF (%) of the performance value into display data SD1C, SD2C.

Please refer to FIG. 4 , FIG. 5A and FIG. 5B . FIG. 4 is a schematic diagram of the controller 310 according to the embodiment of FIG. 3 of the present invention. 5A and 5B are schematic diagrams of a display according to the embodiment of FIG. 2 of the present invention. In this embodiment, the display data SD1C includes display signals a1~g1. Display data SD2C includes display signals a2~g2. The controller 310 outputs the display signals a1~g1 to the seven-segment display SD1. The controller 310 outputs the display signals a2~g2 to the seven-segment display SD2.

Please refer to FIG. 5A and FIG. 6 . FIG. 6 is a circuit diagram of the display according to the embodiment of FIG. 5A of the present invention. The seven-segment display SD1 contains 7 light-emitting diodes. The light emitting diode is a common cathode configuration. The anodes of the light-emitting diodes receive display signals a1~g1 respectively. The cathodes of the light-emitting diodes are commonly coupled to a ground terminal GND (eg, ground terminal GND2). In other embodiments, the light-emitting diodes may have a common anode configuration or a configuration corresponding to other driving modes. The configuration of the light-emitting diodes of the present invention is not limited to this implementation.

The seven light-emitting diodes of the seven-segment display SD1 respectively display messages corresponding to the numbers 0 to 9 according to the display signals a1 to g1. The corresponding relationship between the information displayed by the seven-segment display SD1 and the display signals a1~g1 is shown in Table (1).

The control signal "0" in Table (1) indicates that the signal input to the anode of the light-emitting diode has a low voltage value. Light-emitting diodes do not emit light based on low voltage values. In addition, the control signal "1" indicates that the signal input to the anode of the light-emitting diode has a high voltage value. Light emitting diodes emit light based on high voltage values.

The seven-segment display SD2 shown in FIG. 5B may have the same configuration as the seven-segment display SD1. The seven light-emitting diodes of the seven-segment display SD2 respectively display messages corresponding to the numbers 0 to 9 according to the display signals a2~g2. The corresponding relationship between the information displayed by the seven-segment display SD2 and the display signals a2~g2 is as shown in the following table (2):

FIG. 7 is a schematic diagram of a power supply according to an embodiment of the present invention. Please refer to FIG. 7 . The power supply 700 is provided with two seven-segment displays SD1 and SD2. Displays SD1 and SD2 respectively display tens-digit information and single-digit information of the percentage value of the performance value.

In summary, the power supply according to the embodiment of the present invention can self-measure the working status to obtain high-precision performance value, and can display the performance value in real time. In some embodiments, by compensating the average current value with a compensation value, the present invention can improve the correlation The accuracy of the power value of the input power supply is used to reduce the error of the performance value.

Although the present invention has been disclosed above through embodiments, they are not intended to limit the present invention. Anyone with ordinary knowledge in the technical field may make some modifications 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:Power supply

110: Rectifier

120:Transformer

130: Primary side circuit

131: Primary side voltage sensor

132: Primary side current sensor

140:Secondary side circuit

150:Display components

160:processor

EF: effectiveness value

GND1: ground terminal

IL: average current value

IO: output current value

K: compensation value

LM: Magnetizing inductor

ND1, ND2: nodes

NP: primary side winding

NS: secondary side winding

PM1, PM2: power value

Q1: Power switch

RL: Sampling resistor

SC: control signal

VI: input voltage value

VIN: input power

VL: effective voltage value

VO: output voltage value

VR: Rectified power supply

Claims (12)

A power supply that displays performance, including: a rectifier configured to rectify an input power source; A transformer, including a primary side winding and a primary side winding; A primary side circuit, coupled to the primary side winding and coupled to the rectifier at a first node, includes a sampling resistor and a magnetizing inductor, wherein the sampling resistor and the primary side winding are coupled in series to between the first node and a second node, wherein the exciting inductor is coupled in parallel to the primary side winding; a primary side circuit coupled to the secondary side winding; a display element; and A processor configured to: Receive an effective voltage value between the first node and the second node, receive an average current value of the current flowing through the exciting inductor, receive an input voltage value of the input power supply, receive from the secondary side An output voltage value and an output current value of the circuit, A compensation value is generated based on the input voltage value, a first power value is calculated based on the compensation value, the effective voltage value and the average current value, and a second power value is calculated based on the output voltage value and the output current value, and Calculate a performance value based on the first power value and the second power value, and control the display element to display information corresponding to the performance value. The power supply as described in request item 1, further comprising: a primary-side voltage sensor coupled to the first node, the second node, and the processor, configured to sense the effective voltage value and provide the effective voltage value to the processor, The effective voltage value is the root mean square voltage value located between the first node and the second node. The power supply as described in request item 1, further comprising: A primary-side current sensor coupled to the magnetizing inductor and the processor is configured to sense the average current value and provide the average current value to the processor. The power supply as described in request item 1, further comprising: An input voltage sampling circuit is coupled to the processor and configured to sample the input power supply to obtain the input voltage value and provide the input voltage value to the processor. A power supply as claimed in claim 1, wherein: The transformer also includes a first winding and a second winding, The processor is coupled to the first winding and the second winding, and obtains a first power supply through the transformation operation of the primary side winding and the first winding, and through the transformation operation of the secondary side winding and the second winding. Press operation to obtain a second power source. The power supply as claimed in claim 5, wherein: When receiving the first power source, the processor calculates the first power value, and When receiving the second power source, the processor calculates the second power value. The power supply as claimed in claim 5, wherein: The transformer also includes a third winding, and The power supply also includes: An output voltage sampling circuit, coupled between the third winding and the processor, is configured to obtain the output voltage value through the transforming operation of the secondary side winding and the third winding, and provide the output voltage value to this processor. The power supply as claimed in claim 1, wherein the secondary side circuit includes: An output diode, the anode of the output diode is coupled to the first end of the secondary side winding, and the cathode of the output diode is used as the output end of the secondary side circuit; an output capacitor with a first terminal coupled to the cathode of the output diode; and A primary-side current sensor is coupled between the second terminal of the output capacitor and the second terminal of the secondary-side winding, and is configured to sense the output current value. The power supply of claim 8, wherein the secondary side current sensor includes: a first resistor coupled between the second terminal of the output capacitor and the second terminal of the secondary side winding, configured to provide a voltage value corresponding to the output current value; a second resistor configured to provide a reference resistance value; and a primary side divider, coupled to the first resistor, the second resistor and the processor, configured to receive a voltage value corresponding to the output current value and divide the voltage value corresponding to the output current value Use the reference resistor value to obtain the output current value, and provide the output current value to the processor, The reference resistance value is substantially equal to the resistance value of the first resistor. The power supply as claimed in claim 1, wherein the processor includes: a first divider configured to divide the input voltage value by a time-varying reference voltage value to generate the compensation value, wherein the compensation value is inversely related to the average current value and inversely related to the effective voltage value; a first multiplier, coupled to the first divider, configured to multiply the compensation value, the effective voltage value and the average current value to generate the first power value; a second multiplier configured to multiply the output voltage value and the output current value to generate the second power value; and A second divider, coupled to the first multiplier and the second multiplier, is configured to divide the second power value by the first power value to generate the performance value. The power supply as described in claim 10, wherein the processor further includes: A third multiplier, coupled to the second divider, is configured to multiply the performance value by 100 to generate a percentage value corresponding to the performance value. The power supply as described in claim 11, wherein the processor further includes: A controller, coupled to the third multiplier, is configured to convert the percentage value of the performance value into display data, and control the display element based on the display data.

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