CN214674334U - Current limiting circuit for power supply device - Google Patents
Current limiting circuit for power supply device Download PDFInfo
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- CN214674334U CN214674334U CN202121022325.1U CN202121022325U CN214674334U CN 214674334 U CN214674334 U CN 214674334U CN 202121022325 U CN202121022325 U CN 202121022325U CN 214674334 U CN214674334 U CN 214674334U
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Abstract
The utility model relates to a current-limiting circuit for power supply unit, include first opposition module, second opposition module, first comparison module, second comparison module and frequency control module group, power supply unit carries out the current sample and converts into voltage, and first opposition module carries out the voltage sample and produces first opposition voltage to power supply unit; the second inverting module generates a second inverting voltage according to the first inverting voltage; the first comparison module and the second comparison module execute voltage comparison, when the first reversed-phase voltage is greater than the first comparison voltage, the first comparison module outputs a first warning signal, and when the second reversed-phase 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 first current limiting signal or the second current limiting signal controls the power supply device to operate.
Description
Technical Field
A current limiting circuit, and more particularly, to a current limiting circuit for a power supply device.
Background
Power supply, dc-to-ac conversion's power supply unit such as dc-to-ac converter … are used for providing stable power for electronic equipment, and along with electronic product extensively popularizes, electronic equipment's fineness and performance also promote gradually, and when its output current of power supply unit that electronic equipment connects was too big, cause the inside device of electronic equipment to destroy easily, lead to electronic equipment to break down, consequently need monitor and control power supply unit's output current to the electronic equipment of protection power supply unit rear end.
In order to prevent the influence of the excessive output current on 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, and when the output current value is excessive, the current limiting circuit turns off the power supply output of the power supply device by turning off each control switch in the power supply device, so as to immediately prevent the influence of the excessive output current on the electronic equipment.
However, although the power output of the power supply device is turned off to prevent the excessive output current from damaging the rear-end electronic equipment, the electronic equipment is prone to fail to operate due to the loss of the input power, and the working efficiency of the electronic device is affected.
SUMMERY OF THE UTILITY MODEL
In view of the above, the present invention provides a current limiting circuit for a power device, which reduces an output current value of the power device, and maintains a power output of the power device while limiting the current, so as to solve the problem that the conventional current limiting circuit cannot operate due to the power device being turned off during current limiting.
In order to achieve the foregoing object, the present invention provides a current limiting circuit for a power supply device, wherein the power supply device comprises a control circuit and an output switch module, and the output switch module is controlled by a control signal outputted from the control circuit, and the current limiting circuit comprises:
the first inverting module is provided with an input end and an output end, the input end of the first inverting module is electrically connected with 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 carries out voltage conversion and inverting processing on the sampling voltage to generate a first inverting voltage;
the second inverting module is provided with an input end and an output end, the input end of the second inverting module is electrically connected with the output end of the first inverting module, and when the second inverting module receives the first inverting voltage, the first inverting voltage is subjected to voltage conversion and inverting processing to generate second inverting voltage;
the first comparison module is provided with an input end and an output end, the input end of the first comparison module is electrically connected with the output end of the first inverting module so as to receive the first inverting voltage, the first inverting voltage is compared with a preset first comparison voltage, and when the first inverting voltage is greater than the first comparison voltage, the output end of the first comparison module outputs a first warning signal;
the second comparison module is provided with an input end and an output end, the input end of the second comparison module is electrically connected with the output end of the second reversed-phase module so as to receive the second reversed-phase voltage, the second reversed-phase voltage is compared with a preset second comparison voltage, and when the second reversed-phase 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;
when the frequency control module receives the first warning signal, a first current limiting signal is generated and output to the power supply device, and the power supply device controls the operation of the output switch module according to the first current limiting signal;
when the frequency control module receives the second warning signal, a second current-limiting signal is generated and output to the power supply device, and the power supply device controls the operation of the output switch module according to the second current-limiting signal.
The utility model discloses a comparison of this first reverse phase voltage and this second reverse phase voltage and this first comparison voltage and this second comparison voltage, judge whether too big and need carry out the current-limiting with this output current of this output current and negative phase place when positive phase position, when needs carry out the current-limiting, again through this first current-limiting signal or this second current-limiting signal control this power supply unit's this output switch module function, reach and carry out the purpose of current-limiting to its output of this power supply unit, prevent that rear end electronic equipment from damaging because of too big electric current, and maintain this power supply unit's power output, the electronic equipment of further guarantee rear end can continuously function.
Drawings
Fig. 1 is a schematic diagram of a current limiting circuit for a power supply device according to the present invention.
Fig. 2 is a circuit diagram of a current limiting circuit for a power supply device according to the present invention.
Fig. 3 is a schematic diagram of waveforms for controlling the operation of the switch module according to the present invention.
Fig. 4 is a schematic diagram of a waveform of the switch module controlled by the second current-limiting signal according to the present invention.
Fig. 5 is a schematic diagram of a waveform of the switch module controlled by the first current-limiting signal according to the present invention.
Detailed Description
The following description of the preferred embodiments of the present invention will be made in conjunction with the drawings and the accompanying drawings to further illustrate the technical means adopted to achieve the objects of the present invention.
Referring to fig. 1, the present invention relates to a current limiting circuit 1 for a power device, which is used for a power device 100, the power device 100 includes a control circuit 110 and an output switch module 120, the control circuit 110 outputs a control signal to control the operation of the output switch module 120, the power device 100 performs current sampling and converts the current into voltage, the power device 100 can be an electronic device such as a power supply, an inverter …, etc. that relates to ac/dc conversion and provides power, the current limiting circuit 1 for a power device includes a first inverting module 10, a second inverting module 20, a first comparing module 30, a second comparing module 40, and a frequency control module 50.
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 power supply device 100, and perform voltage amplification and inverting processing on the sampling voltage to generate and output a first inverting voltage. 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, and when the second inverting module 20 receives the first inverting voltage, the first inverting voltage is amplified and inverted to generate and output a second inverting voltage.
The first comparing module 30 has an input terminal and an output terminal, the input terminal of the first comparing module 30 is electrically connected to the output terminal of the first inverting module 10, and an adjustable first comparing voltage is preset in the first comparing module 30, when the first comparing module 30 receives the first inverting voltage, the first comparing module 30 compares the first inverting voltage with the first comparing voltage, and when the first inverting voltage is greater than the first comparing voltage, the first comparing module 30 outputs a first warning signal.
The second comparing module 40 has an input terminal and an output terminal, the input terminal of the second comparing module 40 is electrically connected to the output terminal of the second inverting module 20, and an adjustable second comparing voltage is preset in the second comparing module 40, when the second comparing module 40 receives the second inverting voltage, the second comparing module 40 compares the second inverting voltage with the second comparing voltage, and when the second inverting voltage is greater than the second comparing voltage, the second comparing 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 comparing module 30 and the second comparing 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 comparing module 30 and the second warning signal output by the second comparing 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, and 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 cycle (duty cycle) of the first current limiting signal and the second current limiting signal, for example, reduce the duty cycle of the first current limiting signal and the second current limiting signal, the first current-limiting signal and the second current-limiting signal are then output to the power supply device 100, and the power supply device 100 controls the operation of the output switch module 120 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, the frequency of the first current-limiting signal and the second current-limiting signal does not need to be the same as the frequency of the control signal, 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.
When the power supply apparatus 100 does not receive the first current-limiting signal and the second current-limiting signal, that is, the first inverse voltage is not greater than the first comparison voltage, and the second inverse voltage is not greater than the second comparison voltage, the power supply apparatus 100 controls the on/off of each switch in the output switch module 120 by a control signal output by the control loop 110, so as to control the output power of the power supply apparatus 100; when the first inverse voltage is greater than the first comparison voltage, the current limiting circuit outputs the first current limiting signal to the power supply device 100, the output switch module 120 is controlled by the first current limiting signal to operate, and the first current limiting signal can reduce the on-time of each switch in the output switch module 120 because the duty ratio of the first current limiting signal is smaller than the control signal, thereby reducing the output current value of the output power supply of the power supply device 100; similarly, when the second inverse voltage is greater than the second comparison voltage, the current limiting circuit outputs the second current limiting signal to the power device 100, and the output switch module 120 is controlled by the second current limiting signal, and since the duty cycle of the second current limiting signal is smaller than the control signal, the second current limiting signal can reduce the on-time of each switch in the output switch module 120, and further reduce the output current value of the output power of the power device 100, thereby achieving the purpose of limiting the current of the power device 100.
Referring to fig. 2, a detailed circuit structure of the current limiting circuit 1 for a power supply device according to 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 device 100, and in this embodiment, the output switch module 120 of the power device 100 includes a first switch 121, a second switch 122, a third switch 123 and a fourth switch 124, and the control signal output by the control circuit 110 controls the first switch 121, the second switch 122, the third switch 123 and the fourth switch 124 to operate, wherein the first switch 121, the second switch 122, the third switch 123 and the fourth switch 124 may be mosfet switches.
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 a current sampling and voltage converting output terminal of the power supply device 100, and a positive input terminal of the first inverting amplifier 11 is grounded.
The second inverting module 20 may 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 positive input terminal of the second inverting amplifier 21 is grounded.
The first comparing module 30 can be composed of a first amplifier 31 and a first comparing power source 32, a negative input terminal of the first amplifier 31 is electrically connected to the output terminal of the first inverting amplifier 11, a positive input terminal of the first amplifier 31 is electrically connected to the first comparing power source 32, the first comparing module 30 uses the output voltage of the first comparing power source 32 as the first comparing voltage, and the first comparing module 30 can adjust the first comparing voltage by changing the output voltage of the first comparing power source 32, when the first amplifier 31 determines that the first inverting voltage is greater than the first comparing voltage, the first amplifier 31 outputs the first warning signal.
The second comparing module 40 can be composed of a second amplifier 41 and a second comparing 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, the positive input terminal of the second amplifier 41 is electrically connected to the second comparing power supply 42, the second comparing module 40 uses the output voltage of the second comparing power supply 42 as the second comparing voltage, and the second comparing module 40 can adjust the second comparing voltage by changing the output voltage of the second comparing power supply 42, when the second amplifier 41 determines that the second inverting voltage is greater than the second comparing 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, wherein an input terminal of the first Flip-Flop 51 is electrically connected to an output terminal of the first amplifier 31, an output terminal of the first Flip-Flop 51 is electrically connected to the output switch module 120 of the power device 100, an input terminal of the second Flip-Flop 52 is connected to an output terminal of the second amplifier 41, an output terminal of the second Flip-Flop 52 is electrically connected to the output switch module 120 of the ac/dc converter, and the clock generator 53 is connected to 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 flops), and the first Flip-Flop 51 and the second Flip-Flop 52 use an output clock of the clock generator 53 as the predetermined current limited clock, and the frequency control module 50 can change the output clock of the clock generator 53 to adjust the predetermined current limited clock, 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 ratio of the first current-limiting signal according to the clock of the clock generator 53; 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 adjusts the frequency and duty cycle of the second current-limiting signal according to the clock of the clock generator 53.
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 input end of the logic control 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 device 100, the logic control module 60 includes a logic circuit, one input end of the logic circuit is connected to the control loop 110, the other input end of the logic circuit is connected to the first trigger 51 or the second trigger 52, and 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, and the logic circuit may be 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 flip-flop 51 or the value of the second current limiting signal output by the second flip-flop 52 is logically operated, and according to the logical operation result, 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 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 in the present embodiment. Wherein, the input terminal of the first nand gate 61 is electrically connected to the output terminals of the control loop 110 and the second flip-flop 52; the input terminal of the second nand gate 62 is electrically connected to the output terminals of the control loop 110 and the second flip-flop 52; an input terminal of the third nand gate 63 is electrically connected to the output terminal of the first nand gate 61 and the output terminal of the first flip-flop 51, and an output terminal of the third nand gate 63 is electrically connected to the second switch 122 via a buffer gate 67 (BUF); an input terminal of the fourth nand gate 64 is electrically connected to the output terminal of the second nand gate 62 and the output terminal of the first flip-flop 51, and an output terminal of the fourth nand gate 64 is electrically connected to the fourth switch 124 through a buffer gate 67; the output terminal of the first and gate 65 is electrically connected to the output terminal of the first nand gate 61 and the output terminal of the first flip-flop 51, and the output terminal of the first and gate 65 is electrically connected to the first switch 121 through a buffer gate 67; the input terminal of the second and gate 66 is electrically connected to the output terminal of the second nand gate 62 and the output terminal of the first flip-flop 51, and the output terminal of the second and gate 66 is electrically connected to the third switch 123 through a buffer gate 67.
Referring to fig. 3 to 5, the flow of the first current-limiting signal and the second current-limiting signal controlling the output switch module 120 of the present invention is illustrated by waveform diagrams, 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 circuit 110, V6 corresponds to the waveform of the output signal of the second flip-flop 52, and V7 corresponds to the waveform of the output signal of the first flip-flop 51. Referring to fig. 3, when the first inverted 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 inverted voltage is not greater than the second comparison voltage, the second amplifier 41 outputs the normal state signal through the second flip-flop 52, and the normal state signal is set to a high level in this embodiment, taking the normal state signal as 1 as an example, the control loop 110 outputs the control signal, after the logic control module 60 performs logic operation on the normal state signals of the first flip-flop 51 and the second flip-flop 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.
As shown in fig. 4, when the second inverse voltage is greater than the second comparison voltage, it represents that the output current is too large when the power supply apparatus 100 is in the positive phase, the control loop 110 outputs a control right replacing signal, and the first amplifier 31 outputs the normal state signal through the first flip-flop 51, in this embodiment, the control right replacing signal and the normal state signal are at the high level, that is, the control right replacing signal and the normal state signal are 1 as an example, after the logic control module 60 performs logic operation on the normal state signal output by the first flip-flop 51, the control right replacing signal output by the control loop 110, and the second current limiting signal output by the second flip-flop 52, the logic operation module outputs the second current limiting signal to the output switch module 120, and 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 operate according to the second current-limiting signal, so as to reduce the output current of the power supply device 100 when the power supply device is in the positive phase, thereby achieving the current limitation when the power supply device is in the positive phase.
Referring to fig. 5, when the first inverse voltage is greater than the first comparison voltage, it represents that the output current is too large when the power supply apparatus 100 is in the negative phase, the control loop 110 outputs a control right replacing signal, and the second amplifier 41 outputs the normal state signal through the second flip-flop 52, in this embodiment, the control right replacing signal and the normal state signal are at the high level, that is, the control right replacing signal and the normal state signal are 1 as an example, after the logic control module 60 performs logic operation on the normal state signal output by the second flip-flop 52, the control right replacing signal output by the control loop 110, and the first current limiting signal output by the first flip-flop 51, the logic operation module outputs the first current limiting signal to the output switch module 120, and controls the first switch 121 to be turned off and the second switch 122 to be turned on, and controlling the third switch 123 and the fourth switch 124 to operate according to the first current-limiting signal, so as to reduce the output current of the power device 100 when the power device is in the negative phase, thereby achieving the current limitation in the negative phase.
In addition, the utility model discloses a duty cycle when this first current-limiting signal and this second current-limiting signal reduce this output switch module 120 of this power supply unit 100 and function, through the on-time that reduces each switch, reduces this power supply unit 100's output current value, and maintains this power supply unit 100's power output, keeps the electron device that this power supply unit 100 rear end is connected to last the function.
It should be noted that, in the embodiment, the normal state signal and the control right replacing signal are taken as high level for example, but the normal state signal and the control right alternating signal can also be taken as low level, which is not limited by the embodiment, and the settings of the logic control module 60 and the output switch module 120 can be changed according to the number and arrangement of logic gates and switches, which is not limited by the embodiment.
To sum up, the utility model discloses a current-limiting circuit 1 for power supply unit judges whether this output current of this output current and negative phase when with positive phase and this output current of negative phase are too big and need carry out the current-limiting through this first comparison module 30 and this second comparison module 40 respectively according to this first opposite-phase voltage and this second opposite-phase voltage and the comparison of this first comparison voltage and this second comparison voltage, when this output current of positive phase is too big, this second current-limiting signal control this output switch module 120 of output by this frequency control module 50 is in the switch of positive phase and is moved, because the duty cycle of this second current-limiting signal is less than this control signal, this output current value of its output power when this power supply unit 100 is in positive phase can be reduced to this second current-limiting signal, carry out positive phase current-limiting to this power supply unit 100; similarly, when the output current of the negative phase is too large, the first current-limiting signal outputted by the frequency control module 50 controls the switch of the output switch module 120 in the negative phase, because the duty ratio 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 in the negative phase, and perform negative phase current-limiting on the power supply device 100, therefore, 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, so as to achieve the purpose of current-limiting the output power of the power supply device 100, prevent the rear-end electronic device from being damaged due to too high output current, and further improve the operation stop of the rear-end electronic device due to directly stopping the power output of the power supply device 100 in the prior art, the problem of influencing the operation of the electronic device.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and although the present invention has been described with reference to the preferred embodiment, it is not intended to limit the present invention, and any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical content disclosed above without departing from the technical scope of the present invention, but any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention still fall within the technical scope of the present invention.
Claims (10)
1. A current limiting circuit for a power supply device, wherein the power supply device comprises 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 for the power supply device comprises:
the first inverting module is provided with an input end and an output end, the input end of the first inverting module is electrically connected with 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 carries out voltage conversion and inverting processing on the sampling voltage to generate a first inverting voltage;
the second inverting module is provided with an input end and an output end, the input end of the second inverting module is electrically connected with the output end of the first inverting module, and when the second inverting module receives the first inverting voltage, the first inverting voltage is subjected to voltage conversion and inverting processing to generate second inverting voltage;
the first comparison module is provided with an input end and an output end, the input end of the first comparison module is electrically connected with the output end of the first inverting module so as to receive the first inverting voltage, the first inverting voltage is compared with a preset first comparison voltage, and when the first inverting voltage is greater than the first comparison voltage, the output end of the first comparison module outputs a first warning signal;
the second comparison module is provided with an input end and an output end, the input end of the second comparison module is electrically connected with the output end of the second reversed-phase module so as to receive the second reversed-phase voltage, the second reversed-phase voltage is compared with a preset second comparison voltage, and when the second reversed-phase 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;
when the frequency control module receives the first warning signal, a first current limiting signal is generated and output to the power supply device, and the power supply device controls the operation of the output switch module according to the first current limiting signal;
when the frequency control module receives the second warning signal, a second current-limiting signal is generated and output to the power supply device, and the power supply device controls the operation of the output switch module according to the second current-limiting signal.
2. The current-limiting circuit of claim 1, wherein 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 predetermined 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 of claim 1, wherein when the first inverted voltage is not greater than the first comparison voltage and when the second inverted voltage is not greater than the second comparison voltage, the power device controls the operation of the output switch module according to the control signal output by the control loop;
when the first inverse voltage is larger 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 inverse voltage is larger 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 of claim 1, further comprising:
a logic control module electrically connected between the frequency control module and the control circuit and the output switch module, and including an input terminal, an output terminal and a logic circuit;
the input end of the logic control module is connected with the control loop and the frequency control module, and the output end of the logic control module is connected with the output switch module of the power supply device.
5. The current-limiting circuit of claim 4, wherein the first comparing module outputs a normal state signal via the frequency control module when the first inverted voltage is not greater than the first comparing voltage, and the second comparing module outputs the normal state signal via the frequency control module when the second inverted voltage is not greater than the second comparing voltage, the logic control module outputs the control signal after performing logic operation on each of the normal state signal and the control signal output by the control loop, and the power device controls the output switch module with the control signal;
when the second inverse voltage is larger than the second comparison voltage, the control loop outputs a control right replacing signal, the first comparison module outputs the normal state signal through the frequency control module, the logic control module carries out logic operation by the normal state signal, the control right replacing 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 controls the output switch module by the second current limiting signal;
when the first inverse voltage is larger than the first comparison voltage, the control loop outputs the control right replacing signal, the second comparison module outputs the normal state signal through the frequency control module, the logic control module performs logic operation by the normal state signal, the control right replacing 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 by the first current limiting signal.
6. The current-limiting circuit of claim 1, wherein the first inverting module comprises 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 end of the second inverting amplifier is electrically connected with an output end of the first inverting amplifier, and a positive input end of the second inverting amplifier is grounded.
7. The current-limiting circuit of claim 1, wherein the first comparing module comprises a first amplifier and a first comparing 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 comparing power supply, and the first comparing power supply outputs the first comparing 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 end of the second amplifier is electrically connected with the output end of the second inverting module, a positive input end of the second amplifier is electrically connected with the second comparison power supply, and the second comparison power supply outputs the second comparison voltage to the positive input end of the second amplifier.
8. The current-limiting circuit of claim 1, wherein the frequency control module comprises a first flip-flop, a second flip-flop, and a clock generator, an input terminal of the first flip-flop is electrically connected to the output terminal of the first comparing module, an output terminal of the first flip-flop is electrically connected to the output switch module of the power device, an input terminal of the second flip-flop is connected to the second comparing module, an output terminal of the second flip-flop is electrically connected to the output switch module of the power device, and the clock generator is connected to a clock input terminal of the first flip-flop and the second flip-flop.
9. The current-limiting circuit of claim 8, wherein the first and second flip-flops respectively use the output clock of the clock generator as a predetermined current-limiting clock, the first and second flip-flops respectively adjust the frequency and duty cycles of the first and second current-limiting signals according to the predetermined current-limiting clock, and the duty cycles of the first and second current-limiting signals are smaller than the duty cycle of the control signal.
10. The current-limiting circuit of 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 when the power device 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 when the power device is in a positive phase.
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| CN202121022325.1U CN214674334U (en) | 2021-05-13 | 2021-05-13 | Current limiting circuit for power supply device |
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| CN (1) | CN214674334U (en) |
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2021
- 2021-05-13 CN CN202121022325.1U patent/CN214674334U/en active Active
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