TWI771002B - Current limiting circuits for power supply units - Google Patents

Abstract

The present invention relates to a current limiting circuit for a power supply device, comprising a first inversion module, a second inversion module, a first comparison module, a second comparison module and a frequency control module. The power supply device executes a current The sampling is converted into voltage, the first inversion module generates a first inversion voltage; the second inversion module generates a second inversion voltage according to the first inversion voltage; the first comparison module and the second comparison module execute the voltage comparing, when the first inversion voltage is greater than the first comparison voltage, a first warning signal is output, and when the second inversion voltage is greater than the second comparison voltage, a second warning signal is output; the frequency control module is based on the first warning signal A first current-limiting signal is generated, or a second current-limiting signal is generated 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

Current limiting circuits for power supply units

A current-limiting circuit, especially a current-limiting circuit for a power supply device.

Power supply devices such as power supplies, inverters, etc. that can convert AC to DC are used to provide stable power for electronic equipment. With the widespread popularity of electronic products, the precision and performance of electronic equipment have gradually improved. When electronic equipment is connected When the output current of the power supply device is too large, the internal components of the electronic equipment are easily damaged, resulting in failure of the electronic equipment. Therefore, it is necessary to monitor and control the output current of the power supply device to protect the electronic equipment behind the power supply device.

In order to prevent the excessive output current from affecting the connected electronic equipment, the output current of the power supply device is generally controlled through a current limiting circuit, and an output current value of the power supply device is detected by the current limiting circuit. When the output current value is too large, the The current limiting circuit turns off the power output of the power supply device by turning off each control switch in the power supply device, so as to immediately prevent the excessive output current from affecting the electronic equipment.

However, although turning off the power output of the power supply device can prevent excessive output current from damaging the back-end electronic equipment, it is easy to cause the electronic equipment to fail to operate due to the loss of input power, which affects the working efficiency of the electronic device. It can be seen that the existing current limiting circuit Further improvements are bound to be required.

In view of this, the present invention provides a current limiting circuit for a power supply device, which reduces the output current value of the power supply device on the one hand, and maintains the power output of the power supply device while limiting the current, so as to improve the performance of the conventional current limiting circuit. When the current is limited, the output power of the power supply unit is turned off, resulting in the problem that the electronic equipment cannot operate.

In order to achieve the foregoing, the present invention is used in a current limiting circuit for a power supply device, which is used in 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 output switch module. Group operation, the current limiting circuit of the power supply unit, including: A first inversion module has an input end and an output end, the input end of the first inversion module is electrically connected to the power supply device, and the first inversion module is based on an output current value of the power supply device sampling a corresponding sampling voltage, and performing voltage conversion and inversion processing on the sampling voltage to generate a first inversion voltage; A second inversion module has an input end and an output end, and the input end of the second inversion module is electrically connected to the output end of the first inversion module, and when the second inversion module After receiving the first inversion voltage, perform voltage conversion and inversion processing on the first inversion voltage to generate a second inversion voltage; A first comparison module has an input end and an output end, and the input end of the first comparison module is electrically connected to the output end of the first inversion module to receive the first inversion voltage, and to The first inversion voltage is compared with a preset first comparison voltage, and when the first inversion voltage is greater than the first comparison voltage, the output end of the first comparison module outputs a first warning signal; A second comparison module has an input end and an output end, and the input end of the second comparison module is electrically connected to the output end of the second inversion module to receive the second inversion voltage, and to The second inversion voltage is compared with a preset second comparison voltage, and when the second inversion voltage is greater than the second comparison voltage, the output end 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; Wherein, 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 is based on the first current-limiting signal. controlling the operation of the output switch module; Wherein, 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 is based on the second current-limiting signal Control the operation of the output switch module.

The present invention determines whether the output current in the positive phase and the output current in the negative phase are too large by comparing the first inversion voltage and the second inversion voltage with the first comparison voltage and the second comparison voltage The current limiting needs to be performed. When the current limiting needs to be performed, 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, so as to limit the output power of the power supply device. The purpose of the current is to prevent the back-end electronic equipment from being damaged due to excessive current, and to maintain the power output of the power supply device, further ensuring that the back-end electronic equipment can continue to operate.

The technical means adopted by the present invention to achieve the predetermined purpose of the invention are further described below with reference to the drawings and preferred embodiments of the present invention.

Please refer to FIG. 1 , 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 . A control signal is output to control the operation of the output switch module 120, the power supply device 100 performs current sampling and converts it into a voltage, and the power supply device 100 can be, for example, a power supply, an inverter, etc. related to AC-DC conversion and electronic devices that provide power , the current limiting circuit 1 for a power supply device includes a first inversion module 10, a second inversion module 20, a first comparison module 30, a second comparison module 40, and a frequency control module Group 50.

The first inverter module 10 has an input terminal and an output terminal. The input terminal of the first inverter module 10 is electrically connected to the power supply device 100 for sampling according to an output current value of the output power of the power supply device 100 . a corresponding sampling voltage, and performing voltage amplification and inversion processing on the sampling voltage to generate a first inversion voltage and output it. The second inversion module 20 has an input end and an output end. The input end of the second inversion module 20 is electrically connected to the output end of the first inversion module 10. When the second inversion module 20 After receiving the first inversion voltage, perform voltage amplification and inversion processing on the first inversion voltage to generate and output a second inversion voltage.

The first comparison module 30 has an input end and an output end. The input end of the first comparison module 30 is electrically connected to the output end of the first inversion module 10 , and the first comparison module 30 is internally pre-configured. An adjustable first comparison voltage is provided. When the first comparison module 30 receives the first inversion voltage, the first comparison module 30 performs voltage comparison between the first inversion voltage and 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.

The second comparison module 40 has an input end and an output end. The input end of the second comparison module 40 is electrically connected to the output end of the second inverting module 20 , and the second comparison module 40 is internally preset. An adjustable second comparison voltage is provided. When the second comparison module 40 receives the second inversion voltage, the second comparison module 40 performs voltage comparison between the second inversion voltage and the second comparison voltage , when the second inversion voltage is greater than the second comparison voltage, the second comparison module 40 outputs a second warning signal.

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 frequency control module The output end of 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 The control module 50 generates a first current limit signal according to the first warning signal, or generates a second current limit signal according to the second warning signal, and the frequency control module 50 can be adjusted according to a preset current limit The clock adjusts the frequency of the first current-limiting signal or the second current-limiting signal, and further adjusts the duty cycle of the first current-limiting signal and the second current-limiting signal, for example, reducing the first current-limiting signal the duty ratio of the current limit signal and the second current limit signal, and then output the first current limit signal and the second current limit signal to the power supply device 100, and the power supply device 100 receives the first current limit signal or the second current limit signal. Two current-limiting signals control the operation of the output switch module 120 , wherein the first current-limiting signal and the second current-limiting signal are pulse width modulation (PWM) signals, and the first current-limiting signal and the second current-limiting signal are pulse width modulation (PWM) signals. The frequency of the signal does 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 smaller than the duty cycle of the control signal.

When the power supply device 100 does not receive the first current-limiting signal and the second current-limiting signal, that is, the first inversion voltage is not greater than the first comparison voltage, and the second inversion voltage is not greater than the second comparison voltage voltage, the power supply device 100 is controlled by a control signal output from the control loop 110 to turn on or off each switch in the output switch module 120, thereby controlling the output power of the power supply device 100; and when the first inversion voltage When the 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. When the duty ratio is smaller than the control signal, the first current-limiting signal can reduce the turn-on 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 current-limiting signal is used When the inversion 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 to operate. The duty cycle of the signal is smaller than the control signal, and the second current-limiting signal can reduce the turn-on 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 correct performance. The purpose of the power supply device 100 is to limit the current.

Referring to FIG. 2 , the detailed circuit structure of the current limiting circuit 1 for a power supply device of the present invention will be 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 first Two switches 122 , a third switch 123 and a fourth switch 124 , the first switch 121 , the second switch 122 , the third switch 123 and the fourth switch 124 are controlled by the control signal output from the control loop 110 In operation, the first switch 121 , the second switch 122 , the third switch 123 and the fourth switch 124 can be MOSFET switches.

The first inverting module 10 may be composed of a first inverting amplifier 11 , the 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 the first inverting amplifier 11 The positive input of 11 is grounded.

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

The first comparison module 30 can 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 first amplifier 31 The positive input terminal 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 can change the The output voltage of the first comparison power source 32 adjusts the first comparison voltage. When the first amplifier 31 determines that the first inversion voltage is greater than the first comparison voltage, the first amplifier 31 outputs the first warning signal.

The second comparison module 40 can be composed of a second amplifier 41 and a second comparison power supply 42 , the negative input end of the second amplifier 41 is electrically connected to the output end of the second inverting amplifier 21 , the second amplifier 41 The positive input terminal 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 can change the The output voltage of the second comparison power source 42 adjusts the second comparison voltage. When the second amplifier 41 determines that the second inversion voltage is greater than the second comparison voltage, the second amplifier 41 outputs the second warning signal.

The frequency control module 50 includes a first flip-flop 51 , a second flip-flop 52 and a clock generator 53 . The input terminal of the first flip-flop 51 is electrically connected to the output terminal of the first amplifier 31 . The output terminal of the first flip-flop 51 is electrically connected to the output switch module 120 of the power supply device 100 , the input terminal of the second flip-flop 52 is connected to the output terminal of the second amplifier 41 , and the second flip-flop 52 is connected to the output terminal of the second amplifier 41 . The output terminal of 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 terminals of the first flip-flop 51 and the second flip-flop 52, wherein, The first flip-flop 51 and the second flip-flop 52 can be D flip-flops (D Flip Flop), and the first flip-flop 51 and the second flip-flop 52 use the clock generator 53 The output clock is the default current-limiting clock, the frequency control module 50 can adjust the default current-limiting clock by changing the output clock of the clock generator 53, when the first flip-flop 51 When receiving the first warning signal from the first amplifier 31 , the first flip-flop 51 generates the first current-limiting signal, and adjusts the frequency and the frequency of the first current-limiting signal according to the clock of the clock generator 53 . duty cycle; similarly, when the second flip-flop 52 receives the second warning signal from the second amplifier 41, the second flip-flop 52 generates the second current-limiting signal and generates it according to the clock The clock of the device 53 adjusts the frequency and duty cycle of the second current-limiting signal.

Further, a logic control module 60 may be disposed between the frequency control module 50 and the control loop 110 and the output switch module 120. The logic control module 60 has an input end and an output end. The logic control module 60 The input end of the module 60 is connected to the control loop 110 and the frequency control module 50 , the output end of the logic control module 60 is connected to the output switch module 120 of the power supply device 100 , and the logic control module 60 includes a A logic circuit, one input end of the logic circuit is connected to the control loop 110, the other input end is connected to the first flip-flop 51 or the second flip-flop 52, and the output end of the logic circuit is connected to the output switch mode The first switch 121, the second switch 122, the third switch 123 or the fourth switch 124 in the group 120, the logic circuit can be based on the value of the control signal output by the control loop 110, the first positive The value of the first current-limiting signal output by the inverter 51 or the value of the second current-limiting signal output by the second flip-flop 52 is subjected to a logic operation, and 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.

In this embodiment, the logic circuit includes a first inversion and gate 61 (NAND), a second inversion and gate 62 (NAND), a third inversion and gate 63 (NAND), and a fourth inversion and gate 64 (NAND), a first and gate 65 (AND), a second and gate 66 (AND), and a plurality of same gates 67 (BUF), but the type and combination of the plurality of logic gates are not limited to this embodiment. The input terminal of the first inverter and gate 61 is electrically connected to the control loop 110 and the output terminal of the second flip-flop 52 ; the input terminal of the second inverter and gate 62 is electrically connected to the control loop 110 and the second flip-flop 52 . The output terminal of the flip-flop 52; the input terminal of the third inverter and gate 63 is electrically connected to the output terminal of the first flip-flop and gate 61 and the output terminal of the first flip-flop 51, and the output terminal of the third inverter and gate 63 is electrically connected The output terminal is electrically connected to the second switch 122 through a gate 67 (BUF); the input terminal of the fourth inverter and gate 64 is electrically connected to the output terminal of the second inverter and gate 62 and the output terminal of the first flip-flop 51 , the output terminal of the fourth inverter and gate 64 is electrically connected to the fourth switch 124 through a gate 67 ; the output terminal of the first inverter and gate 65 is electrically connected to the output terminal of the first inverter and the gate 61 and the first positive inverter The output terminal of the switch 51, the output terminal of the first and gate 65 is electrically connected to the first switch 121 through a gate 67; the input terminal of the second and gate 66 is electrically connected to the output terminal of the second inversion gate 62 and the The output end of the first flip-flop 51 , the output end of the second and gate 66 are electrically connected to the third switch 123 via a common gate 67 .

Referring to FIGS. 3 to 5 , the following waveform diagrams are used to illustrate the process of controlling the output switch module 120 by the first current-limiting signal and the second current-limiting signal in the present invention, wherein V1 corresponds to the first switch 121 The signal waveform, 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, and V6 corresponds to the signal waveform of the control loop 110. The waveform of the output signal of the second flip-flop 52 and V7 correspond to the waveform of the output signal of the first flip-flop 51 . As shown in FIG. 3 , when the first inversion voltage is not greater than the first comparison voltage, the first amplifier 31 outputs a normal state signal through the first flip-flop 51 , and when the second inversion voltage is not larger than the first comparison voltage When the voltage is greater than the second comparison voltage, the second amplifier 41 outputs the normal state signal through the second flip-flop 52. In this embodiment, the normal state signal is at a high level, that is, the normal state signal is 1 as an example , and the control loop 110 outputs the control signal, the logic control module 60 uses the normal state signal of the first flip-flop 51 and the second flip-flop 52 and the control signal output by the control loop 110 After the logic operation, the logic control module 60 outputs the control signal to the output switch module 120, and the first switch 121, the second switch 122, the third switch 123 and the fourth switch 124 are controlled by the control signal Alternate action.

As shown in FIG. 4 , when the second inversion voltage is greater than the second comparison voltage, it means that the output current is too large when the power supply device 100 is in the positive phase, the control loop 110 outputs a control right replacement signal, and the first The amplifier 31 outputs the normal state signal through the first flip-flop 51. 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 the For example, the logic control module 60 uses the normal state signal output by the first flip-flop 51 , the control right replacement signal output by the control loop 110 , and the second current-limiting signal output by the second flip-flop 52 . After performing the logic operation, the logic operation module outputs the second current limiting signal to the output switch module 120, controls the third switch 123 to turn on and the fourth switch 124 to turn off, and controls the first switch 121 and the first switch 121 The two switches 122 are actuated according to the second current limiting signal to reduce the output current of the power supply device 100 when it is in the positive phase, so as to achieve the current limiting in the positive phase.

As shown in FIG. 5 , when the first inversion voltage is greater than the first comparison voltage, it means that the output current is too large when the power supply device 100 is in the negative phase, the control loop 110 outputs a control right replacement signal, and the second The amplifier 41 outputs the normal state signal through the second flip-flop 52. In this embodiment, the control right replacement signal and the normal state signal are high levels, that is, the control right replacement signal and the normal state signal are 1 as the For example, the logic control module 60 uses the normal state signal output by the second flip-flop 52 , the control right replacement signal output by the control loop 110 , and the first current-limiting signal output by the first flip-flop 51 . After the logic operation is performed, the logic operation module outputs the first current-limiting signal to the output switch module 120, controls the first switch 121 to close and the second switch 122 to open, and controls the third switch 123 and the first switch The four switches 124 are actuated according to the first current limiting signal to reduce the output current of the power supply device 100 when it is in the negative phase, so as to achieve the current limiting in the negative phase.

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. The output current value of the power supply device 100 is maintained, and the power output of the power supply device 100 is maintained, so that the electronic device connected to the rear end of the power supply device 100 can continue to operate.

It should be noted that, in this 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 can also be low level, which is not the case in this embodiment. The configuration of the logic control module 60 and the output switch module 120 can be changed according to the number and configuration of logic gates and switches, which is not limited to this embodiment.

To sum up, the current limiting circuit 1 for a power supply device of the present invention passes through the first comparison module 30 and the second comparison module 40 according to the first inversion voltage and the second inversion voltage and the first inversion voltage respectively. A comparison voltage is compared with the second comparison voltage to determine whether the output current in the positive phase and the output current in the negative phase are too large and need to be limited. When the output current in the positive phase is too large, the frequency is controlled by the frequency The second current-limiting signal output by the module 50 controls the switching operation of the output switch module 120 in positive phase. Since the duty cycle of the second current-limiting signal is smaller than the control signal, the second current-limiting signal can be reduced When the power supply device 100 is in the positive phase, the output current value of the power supply is outputted, and the positive phase current limit is performed on the power supply device 100; similarly, when the output current of the negative phase is too large, the frequency control module 50 outputs the output current value. The first current-limiting signal controls the switching operation of the output switch module 120 in negative phase. Since the duty cycle of the first current-limiting signal is smaller than that of the control signal, the first current-limiting signal can reduce the power supply device 100 in the When the output current value of the power supply is in the negative phase, the power supply device 100 is subjected to negative phase current limiting. It can be seen that the present invention can pass the first current limiting when the output current value is in the positive phase or the negative phase. The signal or the second current-limiting signal controls the operation of the output switch module 120 of the power supply device 100 to achieve the purpose of limiting the output power of the power supply device 100 to prevent damage to the back-end electronic device caused by excessive output current. And further improve the problem that the operation of the back-end electronic device is stopped due to directly stopping the power output of the power supply device 100 in the prior art, which affects the operation of the electronic device.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Personnel, within the scope of not departing from the technical solution of the present invention, can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content disclosed above, provided that any content that does not depart from the technical solution of the present invention, according to the technical solution of the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solutions of the present invention.

1: Current limiting circuit for power supply unit 10: The first inverting module 11: The first inverting amplifier 20: The second inverting module 21: Second inverting amplifier 30: The first comparison module 31: First Amplifier 32: The first comparison power supply 40: Second Comparison Module 41: Second amplifier 42: Second comparison power supply 50: Frequency control module 51: The first flip-flop 52: The second flip-flop 53: Clock generator 60: Logic control module 61: The first counter and the gate 62: The second counter and gate 63: The third anti and gate 64: The fourth counter and gate 65: First and gate 66: Second and gate 67: Same gate 100: Power supply unit 110: Control loop 120: Output switch module 121: The first switch 122: Second switch 123: The third switch 124: Fourth switch

FIG. 1 is a circuit block diagram of a current limiting circuit used in a power supply device according to the present invention. Figure 2: The circuit diagram of the current limiting circuit used in the power supply device of the present invention. Figure 3: Schematic diagram of the waveform of the control signal to control the operation of the switch module. FIG. 4 is a schematic diagram of the waveform of the switching module controlled by the second current-limiting signal. FIG. 5 is a schematic diagram of the waveform of the switching module controlled by the first current-limiting signal.

1: Current limiting circuit for power supply unit

10: The first inverting module

20: The second inverting module

30: The first comparison module

40: Second Comparison Module

50: Frequency control module

100: Power supply unit

110: Control loop

120: Output switch module

Claims (10)

A current limiting circuit for a power supply device 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 power supply The current limiting circuit of the device, including: A first inversion module has an input end and an output end, the input end of the first inversion module is electrically connected to the power supply device, and the first inversion module is based on an output current value of the power supply device sampling a corresponding sampling voltage, and performing voltage conversion and inversion processing on the sampling voltage to generate a first inversion voltage; A second inversion module has an input end and an output end, and the input end of the second inversion module is electrically connected to the output end of the first inversion module, and when the second inversion module After receiving the first inversion voltage, perform voltage conversion and inversion processing on the first inversion voltage to generate a second inversion voltage; A first comparison module has an input end and an output end, and the input end of the first comparison module is electrically connected to the output end of the first inversion module to receive the first inversion voltage, and to The first inversion voltage is compared with a preset first comparison voltage, and when the first inversion voltage is greater than the first comparison voltage, the output end of the first comparison module outputs a first warning signal; A second comparison module has an input end and an output end, and the input end of the second comparison module is electrically connected to the output end of the second inversion module to receive the second inversion voltage, and to The second inversion voltage is compared with a preset second comparison voltage, and when the second inversion voltage is greater than the second comparison voltage, the output end 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; Wherein, 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 is based on the first current-limiting signal. controlling the operation of the output switch module; Wherein, 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 is based on the second current-limiting signal Control the operation of the output switch module. The current limiting circuit for a power supply device as claimed in claim 1, wherein the frequency control module adjusts the frequency and duty of the first current limiting signal and the second current limiting signal according to a preset current limiting clock ratio, and the duty ratio of the first current-limiting signal and the second current-limiting signal is smaller than the duty ratio of the control signal. The current limiting circuit for a power supply device as claimed in claim 1, wherein when the first inversion voltage is not greater than the first comparison voltage, and when the second inversion 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 inversion 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 inversion 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. The current limiting circuit for a power supply device as described in claim 1, further comprising: a logic control module, electrically connected between the frequency control module and the control loop and the output switch module, and comprising an input end, an output end and a logic circuit; Wherein, 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. The current limiting circuit for a power supply device as claimed in claim 4, wherein when the first inversion voltage is not greater than the first comparison voltage, the first comparison module outputs a normal state via the frequency control module signal, and when the second inversion voltage is not greater than the second comparison voltage, the second comparison module outputs the normal state signal through the frequency control module, and the logic control module uses each of the normal state signals and the After the control signal output by the control loop is subjected to logic operation, the logic control module outputs the control signal, and the power supply device controls the output switch module with the control signal; Wherein, when the second inversion 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 through the frequency control module, and the logic control module outputs the normal state signal. After the group performs 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 for control, and the power supply device uses the first current-limiting signal to control. Two current-limiting signals control the output switch module; Wherein, when the first inversion 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 through the frequency control module, and the logic control module outputs the normal state signal. After the group performs 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 uses the first current-limiting signal. The current limiting signal controls the output switch module. The current limiting circuit for a power supply device according to claim 1, wherein the first inverting module is composed of a first inverting amplifier, and a negative input end of the first inverting amplifier is electrically connected to the power supply device The current sampling is transferred to the voltage output terminal, 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 the second inverting amplifier is A positive input is grounded. The current limiting circuit for a power supply device as claimed in claim 1, wherein the first comparison module is composed of a first amplifier and a first comparison power supply, and a negative input end of the first amplifier is electrically connected to the an output terminal of the first inverter 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; Wherein, 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, and a negative input terminal of the second amplifier is electrically connected to the output terminal of the second inverter module. The positive input terminal 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. The current limiting circuit for a power supply device as claimed in claim 1, wherein the frequency control module comprises a first flip-flop, a second flip-flop and a clock generator, and the first flip-flop has a An input terminal is electrically connected to the output terminal of the first comparison module, an output terminal of the first flip-flop is electrically connected to the output switch module of the power supply device, and an input terminal of the second flip-flop is connected to the second a comparison module, an output terminal of the second flip-flop is electrically connected to the output switch module of the power supply device, and the clock generator is connected to a clock input terminal of the first flip-flop and the second flip-flop . The current limiting circuit for a power supply device according to claim 8, wherein the first flip-flop and the second flip-flop use the output clock of the clock generator as a preset current-limiting clock, The first flip-flop and the second flip-flop 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 first current-limiting signal and The duty cycle of the second current limiting signal is smaller than the duty cycle of the control signal. The current limiting circuit for a power supply device as claimed in claim 1, wherein 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 the power supply device is in negative phase , or use the second current limiting signal to control the operation of the output switch module to reduce the output current value of the power supply device when it is in a positive phase.

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