Current limiting circuit for power supply devices

Abstract

The present invention relates to a current limiting circuit for a power supply device, comprising a first inverting module, a second inverting module, a first comparison module, a second comparison module and a frequency control module. The power supply device performs current sampling and converts it into voltage. The first inverting module performs voltage sampling on the power supply device and generates a first inverting voltage; the second inverting module generates a second inverting voltage according to the first inverting voltage; the first comparison module and the second comparison module perform voltage comparison. When the first inverting voltage is greater than the first comparison voltage, the first comparison module outputs a first warning signal, and when the second inverting voltage is greater than the second comparison voltage, the second comparison module outputs a second warning signal; the frequency control module generates a first current limiting signal according to the first warning signal, or generates a second current limiting signal according to the second warning signal, and the operation of the power supply device is controlled by the first current limiting signal or the second current limiting signal.

Description

Technical Field

[0001] A current limiting circuit, especially a current limiting circuit used in a power supply device. Background Art

[0002] Power supplies, inverters, etc., which can perform AC-DC conversion, are used to provide stable power for electronic devices. As electronic products become more popular, the sophistication and performance of electronic devices are gradually improving. When the output current of the power device connected to the electronic device is too large, it is easy to cause damage to the internal components of the electronic device, resulting in malfunction of the electronic device. Therefore, it is necessary to monitor and control the output current of the power device to protect the electronic equipment behind the power device.

[0003] In order to prevent excessive output current from affecting the connected electronic equipment, the output current of the power supply device is generally controlled by a current limiting circuit. The current limiting circuit detects an output current value of the power supply device. When the output current value is too large, the current limiting circuit turns off each control switch in the power supply device to turn off the power output of the power supply device, thereby immediately preventing the excessive output current from affecting the electronic equipment.

[0004] However, although shutting down the power output of the power supply device can prevent excessive output current from damaging the back-end electronic equipment, it can easily cause the electronic equipment to be unable to operate due to loss of input power, affecting the working efficiency of the electronic device. Therefore, it can be seen that the existing current limiting circuit is bound to need further improvement. Summary of the invention

[0005] In view of this, the present invention provides a current limiting circuit for a power supply device, which on the one hand reduces the output current value of the power supply device, and on the other hand maintains the power output of the power supply device while limiting the current, so as to improve the problem that the conventional current limiting circuit turns off the output power of the power supply device during current limiting, causing the electronic device to fail to operate.

[0006] To achieve the above, the current limiting circuit for a power supply device of the present invention is used for a power supply device, and the power supply device includes a control loop and an output switch module, and the control loop outputs a control signal to control the operation of the output switch module. The current limiting circuit of the power supply device includes:

[0007] a first inverting module having an input terminal and an output terminal, wherein the input terminal of the first inverting module is electrically connected to the power supply device, and the first inverting module samples a corresponding sampling voltage according to an output current value of the power supply device, and performs voltage conversion and inversion processing on the sampling voltage to generate a first inverted voltage;

[0008] a second inverting module having an input terminal and an output terminal, wherein the input terminal of the second inverting module is electrically connected to the output terminal of the first inverting module, and when the second inverting module receives the first inverting voltage, it performs voltage conversion and inversion processing on the first inverting voltage to generate a second inverting voltage;

[0009] a first comparison module having an input terminal and an output terminal, wherein the input terminal of the first comparison module is electrically connected to the output terminal of the first inversion module to receive the first inversion voltage and compare the first inversion voltage with a preset first comparison voltage; when the first inversion voltage is greater than the first comparison voltage, the output terminal of the first comparison module outputs a first warning signal;

[0010] a second comparison module having an input terminal and an output terminal, wherein the input terminal of the second comparison module is electrically connected to the output terminal of the second inversion module to receive the second inversion voltage and compare the second inversion voltage with a preset second comparison voltage. When the second inversion voltage is greater than the second comparison voltage, the output terminal of the second comparison module outputs a second warning signal;

[0011] a frequency control module electrically connected to the output end of the first comparison module and the output end of the second comparison module;

[0012] When the frequency control module receives the first warning signal, it generates a first current limiting signal and outputs the first current limiting signal to the power supply device, and the power supply device controls the output switch module to operate according to the first current limiting signal;

[0013] When the frequency control module receives the second warning signal, it generates a second current limiting signal and outputs the second current limiting signal to the power supply device, and the power supply device controls the output switch module to operate according to the second current limiting signal.

[0014] The present invention determines whether the output current in the positive phase and the output current in the negative phase are too large and need to be limited by comparing the first reverse voltage and the second reverse voltage with the first comparison voltage and the second comparison voltage. When current limiting is required, the output switch module of the power supply device is controlled to operate through the first current limiting signal or the second current limiting signal, thereby achieving the purpose of current limiting the output power of the power supply device, preventing the back-end electronic equipment from being damaged due to excessive current, maintaining the power output of the power supply device, and further ensuring that the back-end electronic equipment can continue to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The figure is a circuit block diagram of a current limiting circuit for a power supply device according to the present invention.

[0016] Figure 2The circuit diagram of the current limiting circuit used for the power supply device of the present invention is shown in FIG.

[0017] Figure 3 It is a waveform diagram of the operation of the switch module controlled by the control signal in the present invention.

[0018] Figure 4 It is a waveform diagram of the operation of the switch module controlled by the second current limiting signal in the present invention.

[0019] Figure 5 It is a waveform diagram of the operation of the switch module controlled by the first current limiting signal in the present invention. DETAILED DESCRIPTION

[0020] The following is a detailed description of the technical means used by the present invention to achieve the intended purpose of the invention with reference to the drawings and preferred embodiments of the present invention.

[0021] Please see Figure 1 As shown, the present invention is a current limiting circuit 1 for a power supply device, which is used for a power supply device 100. The power supply device 100 includes a control loop 110 and an output switch module 120. The control loop 110 outputs a control signal to control the operation of the output switch module 120. The power supply device 100 performs current sampling and converts it into voltage. The power supply device 100 can be, for example, a power supply, an inverter, etc., an electronic device involving AC-DC conversion and power supply. The current limiting circuit 1 for the power supply device includes a first inverting module 10, a second inverting module 20, a first comparison module 30, a second comparison module 40, and a frequency control module 50.

[0022] The first inverting module 10 has an input terminal and an output terminal. The input terminal of the first inverting module 10 is electrically connected to the power supply device 100 to sample a corresponding sampling voltage according to an output current value of the output power of the power supply device 100, and perform voltage amplification and inversion processing on the sampling voltage to generate a first inverted voltage and output it. The second inverting module 20 has an input terminal and an output terminal. The input terminal of the second inverting module 20 is electrically connected to the output terminal of the first inverting module 10. After the second inverting module 20 receives the first inverted voltage, it performs voltage amplification and inversion processing on the first inverted voltage to generate a second inverted voltage and output it.

[0023] The first comparison module 30 has an input terminal and an output terminal. The input terminal of the first comparison module 30 is electrically connected to the output terminal of the first inversion module 10. The first comparison module 30 is preset with an adjustable first comparison voltage. When the first comparison module 30 receives the first inversion voltage, the first comparison module 30 compares the first inversion voltage with the first comparison voltage. When the first inversion voltage is greater than the first comparison voltage, the first comparison module 30 outputs a first warning signal.

[0024] The second comparison module 40 has an input terminal and an output terminal. The input terminal of the second comparison module 40 is electrically connected to the output terminal of the second inverting module 20. An adjustable second comparison voltage is preset inside the second comparison module 40. When the second comparison module 40 receives the second inverting voltage, the second comparison module 40 compares the second inverting voltage with the second comparison voltage. When the second inverting voltage is greater than the second comparison voltage, the second comparison module 40 outputs a second warning signal.

[0025] The frequency control module 50 has an input end and an output end. The input end of the frequency control module 50 is electrically connected to the output ends of the first comparison module 30 and the second comparison module 40. The output end of the frequency control module 50 is electrically connected to the power supply device 100. The frequency control module 50 receives the first warning signal output by the first comparison module 30 and the second warning signal output by the second comparison module 40. The frequency control module 50 generates a first current limiting signal according to the first warning signal, or generates a second current limiting signal according to the second warning signal. The frequency control module 50 can adjust the frequency of the first current limiting signal or the second current limiting signal according to an adjustable preset current limiting clock, and further adjust the duty ratio (duty) of the first current limiting signal and the second current limiting signal. cycle), for example, reducing the duty cycle of the first current limiting signal and the second current limiting signal, and then outputting the first current limiting signal and the second current limiting signal to the power supply device 100, and the power supply device 100 controls the output switch module 120 to operate by the first current limiting signal or the second current limiting signal, wherein the first current limiting signal and the second current limiting signal are pulse width modulation (PWM) signals, and the frequencies of the first current limiting signal and the second current limiting signal do not need to be the same as the frequency of the control signal, and the duty cycle of the first current limiting signal and the second current limiting signal is less than the duty cycle of the control signal.

[0026] When the power supply device 100 does not receive the first current limiting signal and the second current limiting signal, that is, the first reverse voltage is not greater than the first comparison voltage, and the second reverse voltage is not greater than the second comparison voltage, the power supply device 100 controls the opening or closing of each switch in the output switch module 120 by a control signal output by the control loop 110, thereby controlling the output power of the power supply device 100; and when the first reverse voltage is greater than the first comparison voltage, the current limiting circuit outputs the first current limiting signal to the power supply device 100, and the output switch module 120 is controlled by the first current limiting signal to operate. Since the duty cycle of the first current limiting signal is less than that of the control signal , the first current limiting signal can reduce the opening time of each switch in the output switch module 120, thereby reducing the output current value of the output power of the power supply device 100; similarly, when the second reverse voltage is greater than the second comparison voltage, the current limiting circuit outputs the second current limiting signal to the power supply device 100, and the output switch module 120 is controlled by the second current limiting signal. Since the duty cycle of the second current limiting signal is less than the control signal, the second current limiting signal can reduce the opening time of each switch in the output switch module 120, thereby reducing the output current value of the output power of the power supply device 100, thereby achieving the purpose of current limiting the power supply device 100.

[0027] Please see Figure 2 As shown, the detailed circuit structure of the current limiting circuit 1 for a power supply device of the present invention is described below. The current limiting circuit is connected between a power input terminal and a power output terminal of the power supply device 100. In this embodiment, the output switch module 120 of the power supply device 100 includes a first switch 121, a second switch 122, a third switch 123 and a fourth switch 124. The control signal output by the control loop 110 controls the operation of the first switch 121, the second switch 122, the third switch 123 and the fourth switch 124. The first switch 121, the second switch 122, the third switch 123 and the fourth switch 124 can be metal oxide semi-conductor field effect transistor switches.

[0028] The first inverting module 10 may be composed of a first inverting amplifier 11 , a negative input terminal of the first inverting amplifier 11 is electrically connected to the current sampling to voltage output terminal of the power supply device 100 , and a positive input terminal of the first inverting amplifier 11 is grounded.

[0029] The second inverting module 20 may be composed of a second inverting amplifier 21 , a negative input terminal of the second inverting amplifier 21 is electrically connected to the output terminal of the first inverting amplifier 11 , and a positive input terminal of the second inverting amplifier 21 is grounded.

[0030] The first comparison module 30 may be composed of a first amplifier 31 and a first comparison power supply 32. The negative input terminal of the first amplifier 31 is electrically connected to the output terminal of the first inverting amplifier 11, and the positive input terminal of the first amplifier 31 is electrically connected to the first comparison power supply 32. The first comparison module 30 uses the output voltage of the first comparison power supply 32 as the first comparison voltage, and the first comparison module 30 may adjust the first comparison voltage by changing the output voltage of the first comparison power supply 32. When the first amplifier 31 determines that the first inverting voltage is greater than the first comparison voltage, the first amplifier 31 outputs the first warning signal.

[0031] The second comparison module 40 may be composed of a second amplifier 41 and a second comparison power supply 42. The negative input terminal of the second amplifier 41 is electrically connected to the output terminal of the second inverting amplifier 21, and the positive input terminal of the second amplifier 41 is electrically connected to the second comparison power supply 42. The second comparison module 40 uses the output voltage of the second comparison power supply 42 as the second comparison voltage, and the second comparison module 40 may adjust the second comparison voltage by changing the output voltage of the second comparison power supply 42. When the second amplifier 41 determines that the second inverting voltage is greater than the second comparison voltage, the second amplifier 41 outputs the second warning signal.

[0032] The frequency control module 50 includes a first trigger 51, a second trigger 52 and a clock generator 53. The input end of the first trigger 51 is electrically connected to the output end of the first amplifier 31, the output end of the first trigger 51 is electrically connected to the output switch module 120 of the power supply device 100, the input end of the second trigger 52 is connected to the output end of the second amplifier 41, the output end of the second trigger 52 is electrically connected to the output switch module 120 of the AC / DC converter, and the clock generator 53 is connected to the clock input ends of the first trigger 51 and the second trigger 52, wherein the first trigger 51 and the second trigger 52 can be D flip-flops (D Flip Flops). Flop), and the first trigger 51 and the second trigger 52 use the output clock of the clock generator 53 as the preset current limiting clock. The frequency control module 50 can adjust the preset current limiting clock by changing the output clock of the clock generator 53. When the first trigger 51 receives the first warning signal from the first amplifier 31, the first trigger 51 generates the first current limiting signal, and adjusts the frequency and duty cycle of the first current limiting signal according to the clock of the clock generator 53; similarly, when the second trigger 52 receives the second warning signal from the second amplifier 41, the second trigger 52 generates the second current limiting signal, and adjusts the frequency and duty cycle of the second current limiting signal according to the clock of the clock generator 53.

[0033] Furthermore, a logic control module 60 may be provided between the frequency control module 50, the control loop 110 and the output switch module 120. The logic control module 60 has an input end and an output end. The input end of the logic control module 60 is connected to the control loop 110 and the frequency control module 50, and the output end of the logic control module 60 is connected to the output switch module 120 of the power supply device 100. The logic control module 60 includes a logic circuit, one of the input ends of the logic circuit is connected to the control loop 110, and the other input end is connected to the first trigger 51 or the second trigger 52. The output end of the logic circuit is connected to the first switch 121, the second switch 122, the third switch 123 or the fourth switch 124 in the output switch module 120. The logic circuit can perform a logic operation according to the value of the control signal output by the control loop 110, the value of the first current limiting signal output by the first trigger 51 or the value of the second current limiting signal output by the second trigger 52. According to the result of the logic operation, the first switch 121, the second switch 122, the third switch 123 and the fourth switch 124 can be controlled by the control signal, the first current limiting signal or the second current limiting signal.

[0034] In the present embodiment, the logic circuit includes a first NAND gate 61 (NAND), a second NAND gate 62 (NAND), a third NAND gate 63 (NAND), a fourth NAND gate 64 (NAND), a first AND gate 65 (AND), a second AND gate 66 (AND) and a plurality of buffer gates 67 (BUF), but the types and combinations of the plurality of logic gates are not limited to the present embodiment. Among them, the input end of the first NAND gate 61 is electrically connected to the output end of the control loop 110 and the second flip-flop 52; the input end of the second NAND gate 62 is electrically connected to the output end of the control loop 110 and the second flip-flop 52; the input end of the third NAND gate 63 is electrically connected to the output end of the first NAND gate 61 and the output end of the first flip-flop 51, and the output end of the third NAND gate 63 is electrically connected to the second switch 122 via a buffer gate 67 (BUF); the input end of the fourth NAND gate 64 is electrically connected to the output end of the second NAND gate 62 and the output end of the third NAND gate 63. The output end of a trigger 51, the output end of the fourth AND gate 64 is electrically connected to the fourth switch 124 via a buffer gate 67; the output end of the first AND gate 65 is electrically connected to the output end of the first AND gate 61 and the output end of the first trigger 51, and the output end of the first AND gate 65 is electrically connected to the first switch 121 via a buffer gate 67; the input end of the second AND gate 66 is electrically connected to the output end of the second AND gate 62 and the output end of the first trigger 51, and the output end of the second AND gate 66 is electrically connected to the third switch 123 via a buffer gate 67.

[0035] Please see Figures 3 to 5As shown, the following waveform diagram is used to illustrate the process of the first current limiting signal and the second current limiting signal controlling the output switch module 120 in the present invention, wherein V1 corresponds to the signal waveform of the first switch 121, V2 corresponds to the signal waveform of the second switch 122, V3 corresponds to the signal waveform of the third switch 123, V4 corresponds to the signal waveform of the fourth switch 124, V5 corresponds to the waveform of the output signal of the control loop 110, V6 corresponds to the waveform of the output signal of the second trigger 52, and V7 corresponds to the waveform of the output signal of the first trigger 51. Figure 3 As shown, when the first inverting voltage is not greater than the first comparison voltage, the first amplifier 31 outputs a normal state signal via the first trigger 51, and when the second inverting voltage is not greater than the second comparison voltage, the second amplifier 41 outputs the normal state signal via the second trigger 52. In this embodiment, the normal state signal is at a high level, that is, the normal state signal is 1 for example, and the control loop 110 outputs the control signal. After the logic control module 60 performs a logic operation on the normal state signals of the first trigger 51 and the second trigger 52 and the control signal output by the control loop 110, the logic control module 60 outputs the control signal to the output switch module 120, and the control signal controls the first switch 121, the second switch 122, the third switch 123 and the fourth switch 124 to alternately operate.

[0036] Cooperate Figure 4 As shown, when the second inverting voltage is greater than the second comparison voltage, it means that the output current of the power supply device 100 is too large when it is in the positive phase, and the control loop 110 outputs a control right replacement signal, and the first amplifier 31 outputs the normal state signal via the first trigger 51. In this embodiment, the control right replacement signal and the normal state signal are at a high level, that is, the control right replacement signal and the normal state signal are 1 as an example. After the logic control module 60 performs a logic operation on the normal state signal output by the first trigger 51, the control right replacement signal output by the control loop 110, and the second current limiting signal output by the second trigger 52, the logic operation module outputs the second current limiting signal to the output switch module 120, controls the third switch 123 to be turned on and the fourth switch 124 to be turned off, and controls the first switch 121 and the second switch 122 to be actuated according to the second current limiting signal, thereby reducing the output current of the power supply device 100 when it is in the positive phase, and achieving current limiting in the positive phase.

[0037] Cooperate Figure 5As shown, when the first reverse voltage is greater than the first comparison voltage, it means that the output current of the power supply device 100 is too large when it is in the negative phase, and the control loop 110 outputs a control right replacement signal, and the second amplifier 41 outputs the normal state signal via the second trigger 52. In this embodiment, the control right replacement signal and the normal state signal are high level, that is, the control right replacement signal and the normal state signal are 1 as an example. After the logic control module 60 performs a logic operation on the normal state signal output by the second trigger 52, the control right replacement signal output by the control loop 110, and the first current limiting signal output by the first trigger 51, the logic operation module outputs the first current limiting signal to the output switch module 120, controls the first switch 121 to be closed and the second switch 122 to be opened, and controls the third switch 123 and the fourth switch 124 to be actuated according to the first current limiting signal, thereby reducing the output current of the power supply device 100 when it is in the negative phase, and achieving current limiting in the negative phase.

[0038] In addition, the present invention reduces the duty cycle of the output switch module 120 of the power supply device 100 during operation through the first current limiting signal and the second current limiting signal, reduces the output current value of the power supply device 100 by reducing the opening time of each switch, and maintains the power output of the power supply device 100, thereby keeping the electronic device connected to the back end of the power supply device 100 able to operate continuously.

[0039] It should be noted that, in the present embodiment, the normal state signal and the control right replacement signal are taken as high level as an example, but the normal state signal and the control right replacement signal may also be low level, which is not limited to the present embodiment, and the configuration of the logic control module 60 and the output switch module 120 may be changed according to the number and configuration of logic gates and switches, which is not limited to the present embodiment.

[0040] In summary, the current limiting circuit 1 for a power supply device of the present invention determines whether the output current in the positive phase and the output current in the negative phase are too large and need to be limited according to the comparison of the first reverse voltage and the second reverse voltage with the first comparison voltage and the second comparison voltage respectively by the first comparison module 30 and the second comparison module 40. When the output current in the positive phase is too large, the second current limiting signal output by the frequency control module 50 controls the switch action of the output switch module 120 in the positive phase. Since the duty cycle of the second current limiting signal is smaller than the control signal, the second current limiting signal can reduce the output current value of the output power of the power supply device 100 when it is in the positive phase, and perform positive phase current limiting on the power supply device 100. Similarly, when the output current in the negative phase is too large, the frequency control module 50 controls the output current of the output switch module 120 in the positive phase. The output first current limiting signal controls the switching action of the output switch module 120 in the negative phase. Since the duty cycle of the first current limiting signal is smaller than the control signal, the first current limiting signal can reduce the output current value of the output power of the power supply device 100 when it is in the negative phase, and perform negative phase current limiting on the power supply device 100. It can be seen that the present invention can control the operation of the output switch module 120 of the power supply device 100 through the first current limiting signal or the second current limiting signal when the output current value is in the positive phase or the negative phase, thereby achieving the purpose of current limiting the output power of the power supply device 100, preventing damage to the back-end electronic device caused by excessive output current, and further improving the problem of the known technology causing the operation of the back-end electronic device to stop due to directly stopping the power output of the power supply device 100, thereby affecting the operation of the electronic device.

[0041] The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been described above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technical personnel in this field can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A current limiting circuit for a power supply device, characterized in that: A power supply device is used, and the power supply device includes a control circuit and an output switch module, and the control circuit outputs a control signal to control the operation of the output switch module. The current limiting circuit of the power supply device is characterized by comprising: a first inverting module having an input terminal and an output terminal, wherein the input terminal of the first inverting module is electrically connected to the power supply device, and the first inverting module samples a corresponding sampling voltage according to an output current value of the power supply device, and performs voltage conversion and inversion processing on the sampling voltage to generate a first inverted voltage; a second inverting module having an input terminal and an output terminal, wherein the input terminal of the second inverting module is electrically connected to the output terminal of the first inverting module, and when the second inverting module receives the first inverting voltage, it performs voltage conversion and inversion processing on the first inverting voltage to generate a second inverting voltage; a first comparison module having an input terminal and an output terminal, wherein the input terminal of the first comparison module is electrically connected to the output terminal of the first inversion module to receive the first inversion voltage and compare the first inversion voltage with a preset first comparison voltage; when the first inversion voltage is greater than the first comparison voltage, the output terminal of the first comparison module outputs a first warning signal; a second comparison module having an input terminal and an output terminal, wherein the input terminal of the second comparison module is electrically connected to the output terminal of the second inversion module to receive the second inversion voltage and compare the second inversion voltage with a preset second comparison voltage. When the second inversion voltage is greater than the second comparison voltage, the output terminal of the second comparison module outputs a second warning signal; a frequency control module electrically connected to the output end of the first comparison module and the output end of the second comparison module; When the frequency control module receives the first warning signal, it generates a first current limiting signal and outputs the first current limiting signal to the power supply device, and the power supply device controls the output switch module to operate according to the first current limiting signal; When the frequency control module receives the second warning signal, it generates a second current limiting signal and outputs the second current limiting signal to the power supply device, and the power supply device controls the output switch module to operate according to the second current limiting signal.

2. The current limiting circuit for a power supply device according to claim 1, characterized in that: in, The frequency control module adjusts the frequency and duty cycle of the first current limiting signal and the second current limiting signal according to a preset current limiting clock, and the duty cycle of the first current limiting signal and the second current limiting signal is smaller than the duty cycle of the control signal.

3. The current limiting circuit for a power supply device according to claim 1, characterized in that: in, When the first reverse voltage is not greater than the first comparison voltage, and when the second reverse voltage is not greater than the second comparison voltage, the power supply device controls the output switch module to operate according to the control signal output by the control loop; When the first reverse voltage is greater than the first comparison voltage, the power supply device controls the output switch module to operate according to the first current limiting signal; When the second reverse voltage is greater than the second comparison voltage, the power supply device controls the output switch module to operate according to the second current limiting signal.

4. The current limiting circuit for a power supply device according to claim 1, characterized in that: Further included are: A logic control module, electrically connected between the frequency control module, the control loop and the output switch module, and comprising an input terminal, an output terminal and a logic circuit; The input end of the logic control module is connected to the control loop and the frequency control module, and the output end of the logic control module is connected to the output switch module of the power supply device.

5. The current limiting circuit for a power supply device according to claim 4, characterized in that: in, When the first reverse voltage is not greater than the first comparison voltage, the first comparison module outputs a normal state signal via the frequency control module, and when the second reverse voltage is not greater than the second comparison voltage, the second comparison module outputs the normal state signal via the frequency control module, and after the logic control module performs a logic operation on each of the normal state signals and the control signal output by the control loop, the logic control module outputs the control signal, and the power supply device controls the output switch module with the control signal; When the second reverse voltage is greater than the second comparison voltage, the control loop outputs a control right replacement signal, and the first comparison module outputs the normal state signal via the frequency control module. After the logic control module performs a logic operation on the normal state signal, the control right replacement signal output by the control loop, and the second current limiting signal, the logic operation module outputs the second current limiting signal to control the output switch module by the power supply device using the second current limiting signal. Among them, when the first reverse voltage is greater than the first comparison voltage, the control loop outputs the control right replacement signal, and the second comparison module outputs the normal state signal via the frequency control module. After the logic control module performs a logic operation on the normal state signal, the control right replacement signal output by the control loop and the first current limiting signal, the logic operation module outputs the first current limiting signal, and the power supply device controls the output switch module with the first current limiting signal.

6. The current limiting circuit for a power supply device according to claim 1, characterized in that: in, The first inverting module is composed of a first inverting amplifier, a negative input terminal of the first inverting amplifier is electrically connected to the current sampling to voltage output terminal of the power supply device, and a positive input terminal of the first inverting amplifier is grounded; The second inverting module is composed of a second inverting amplifier, a negative input terminal of the second inverting amplifier is electrically connected to an output terminal of the first inverting amplifier, and a positive input terminal of the second inverting amplifier is grounded.

7. The current limiting circuit for a power supply device according to claim 1, characterized in that: in, The first comparison module is composed of a first amplifier and a first comparison power supply, a negative input terminal of the first amplifier is electrically connected to the output terminal of the first inverting module, a positive input terminal of the first amplifier is electrically connected to the first comparison power supply, and the first comparison power supply outputs the first comparison voltage to the positive input terminal of the first amplifier; The second comparison module is composed of a second amplifier and a second comparison power supply, a negative input terminal of the second amplifier is electrically connected to the output terminal of the second inverting module, a positive input terminal of the second amplifier is electrically connected to the second comparison power supply, and the second comparison power supply outputs the second comparison voltage to the positive input terminal of the second amplifier.

8. The current limiting circuit for a power supply device according to claim 1, characterized in that: in, The frequency control module includes a first trigger, a second trigger and a clock generator, an input end of the first trigger is electrically connected to the output end of the first comparison module, an output end of the first trigger is electrically connected to the output switch module of the power supply device, an input end of the second trigger is connected to the second comparison module, an output end of the second trigger is electrically connected to the output switch module of the power supply device, and the clock generator is connected to a clock input end of the first trigger and the second trigger.

9. The current limiting circuit for a power supply device according to claim 8, characterized in that: in, The first trigger and the second trigger use the output clock of the clock generator as a preset current limiting clock. The first trigger and the second trigger adjust the frequency and duty cycle of the first current limiting signal and the second current limiting signal according to the preset current limiting clock, and the duty cycle of the first current limiting signal and the second current limiting signal is less than the duty cycle of the control signal.

10. The current limiting circuit for a power supply device according to claim 1, characterized in that: The frequency control module controls the operation of the output switch module with the first current limiting signal to reduce the output current value of the power supply device when it is in a negative phase, or controls the operation of the output switch module with the second current limiting signal to reduce the output current value of the power supply device when it is in a positive phase.

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