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CN-122000828-A - Counting type overcurrent protection circuit and protection method for AC overcurrent detection

CN122000828ACN 122000828 ACN122000828 ACN 122000828ACN-122000828-A

Abstract

The invention discloses a counting type overcurrent protection circuit and a protection method for AC overcurrent detection, which can count time and judge energy accumulation aiming at AC transient overcurrent, remarkably improve the reliability of a system, better protect devices and prolong the service life of the devices, the circuit comprises a current detection module, a high-speed comparator, a reset module, a period control module, a counter module and an overcurrent protection logic module, wherein the current detection module is used for outputting detection current and generating corresponding voltage signals, the voltage signal is connected to the positive input end of the high-speed comparator, the negative input end of the high-speed comparator is connected to the reference voltage, the high-speed comparator is used for comparing the voltage signal with the reference voltage, if the duration of the voltage signal exceeding the reference voltage is greater than a first threshold value, the high-speed comparator outputs a high level, the reset module is used for detecting the overcurrent time, and if the duration of the overcurrent is detected to exceed a second threshold value, the high level is output to reset the current detection module; the period control module is used for resetting the counter module when the period is ended, if the output of the high-speed comparator jumps once, the counter module counts value +1, and when the count reaches a set count threshold value, the OCP signal is triggered to execute the overcurrent protection action through the overcurrent protection logic module.

Inventors

  • SHI SHUNJI
  • XIA QIN
  • WANG YUAN
  • WANG WEIZHONG

Assignees

  • 陕西亚成微电子股份有限公司

Dates

Publication Date
20260508
Application Date
20251230

Claims (10)

  1. 1. The counting type overcurrent protection circuit for the alternating current overcurrent detection is characterized by comprising a current detection module, wherein the current detection module is used for outputting detection current and generating corresponding voltage signals, the output end of the current detection module is connected with the positive input end of a high-speed comparator, the voltage signals are connected with the positive input end of the high-speed comparator, the negative input end of the high-speed comparator is connected with reference voltage, the high-speed comparator is used for comparing the voltage signals generated by the current detection module with the reference voltage, if the duration of the voltage signals exceeding the reference voltage is longer than a first threshold value, the high-speed comparator outputs high level, the output end of the current detection module is also connected with a reset module, the input end of the reset module is connected with the output end of the high-speed comparator, the reset module is used for detecting overcurrent time, if the duration of the detected overcurrent exceeds a second threshold value, the output end of the high-speed comparator is connected with a period control module, the output end of the counter module is connected with an overcurrent protection logic module, the period control module is used for resetting the counter module when the period is ended, the counter module is in a period of time, the counter is triggered, and the count value reaches the threshold value after the counter logic is triggered after the counter module is in a certain time, the logic value is triggered, and the counter logic is triggered after the counter logic module is in an overcurrent state, the counter logic state reaches the counter logic state, and the counter logic state is triggered.
  2. 2. The counting type overcurrent protection circuit for the alternating current and overcurrent detection according to claim 1, wherein the current detection module comprises a current detection circuit and a resistor RS, a first output end of the current detection circuit is connected with one end of the resistor RS, the other end of the resistor RS is connected with GND, and a second output end of the current detection circuit is respectively connected with a positive input end of the high-speed comparator and the reset module.
  3. 3. The counting type overcurrent protection circuit for the alternating current and overcurrent detection according to claim 2, wherein the reset module comprises a duration judging circuit and an NMOS reset tube, a drain electrode of the NMOS reset tube is connected with a second output end of the current detection circuit, a source electrode of the NMOS reset tube is connected with GND, a grid electrode of the NMOS reset tube is connected with an output end of the duration judging circuit, and an input end of the duration judging circuit is connected with an output end of the high-speed comparator.
  4. 4. The counting type overcurrent protection circuit for detecting the alternating current and the overcurrent according to claim 3, wherein the duration judging circuit comprises a rising edge delay module and a logic AND gate, a first path of an output signal of the high-speed comparator enters the rising edge delay module, the first input end of the logic AND gate is input after the delay, a second path of the output signal of the high-speed comparator enters a second input end of the logic AND gate, and the output of the logic AND gate is connected with the grid electrode of the NMOS reset tube and is used for controlling the on or off of the NMOS reset tube.
  5. 5. The counting type overcurrent protection circuit for detecting the alternating current and the overcurrent according to claim 4, wherein the duration judging circuit detects that the overcurrent time exceeds 1us continuously, the duration judging circuit outputs a high level, and the voltage signal output by the current detecting module is reset through the NMOS reset tube.
  6. 6. The counting type overcurrent protection circuit for the alternating current and overcurrent detection according to claim 1, wherein the counter module comprises four D flip-flops, R ends of the four D flip-flops are all connected with output ends of the period control module, D ends of the four D flip-flops are all connected with respective QN ends, CLK ends of the D flip-flops D1 are connected with output ends of the high-speed comparator, Q ends of the D flip-flops D1 are respectively 1 counting output, CLK ends of the D flip-flops are connected with QN output ends of the D flip-flops D1, CLK ends of the D flip-flops D3 are respectively connected with QN output ends of the D flip-flops D2, CLK ends of the D flip-flops D4 are respectively 2 counting outputs, Q ends of the D flip-flops D3 are respectively 4 counting outputs, and Q ends of the D flip-flops D4 are respectively 8 counting outputs.
  7. 7. A counting type overcurrent protection method for detecting an alternating current and an overcurrent, characterized in that the counting type overcurrent protection circuit for detecting the alternating current and the overcurrent is adopted according to any one of claims 1 to 6, and the method comprises the following steps: 1) The period control module sets an OCP observation period, and clears the count value of the counter module after each observation period is finished; 2) The current detection module continuously detects the system current and inputs a voltage signal to the positive input end of the high-speed comparator; 3) If the duration of the voltage signal exceeding the reference voltage is longer than a first threshold value, the high-speed comparator outputs a high level, the high-speed comparator outputs a jump once, and the counter module counts value +1; 4) If the high-level duration time output by the high-speed comparator is greater than the second threshold value, resetting the current signal by the resetting module, and pulling down the output of the high-speed comparator; 5) If the count of the counter module exceeds the count threshold, the counter module outputs an OCP signal to the overcurrent protection logic module, and the overcurrent protection logic module performs overcurrent protection.
  8. 8. The method for counting type over-current protection for ac-current detection according to claim 9, wherein the first threshold is 1 ns-100 ns and the second threshold is 1 μs.
  9. 9. The counting type overcurrent protection method for the alternating current overcurrent detection according to claim 9, wherein the OCP observation period is 4-10 μs.
  10. 10. The method for counting type over-current protection for detecting an over-current according to claim 9, wherein the counting threshold is 2-8 times.

Description

Counting type overcurrent protection circuit and protection method for AC overcurrent detection Technical Field The invention relates to the technical field of overcurrent protection, in particular to a counting type overcurrent protection circuit and a protection method for detecting alternating current and overcurrent. Background The prior art Over-current protection (OCP) circuit is mostly based on the duration of the direct current, for example, the protection mechanism is triggered when the Over-current lasts more than 1-4 microseconds (μs). However, in ac load or high speed switching applications, spike overstretches (Spurious Spike Current) often occur, which last only 1 nanosecond (ns) to 100 nanoseconds (ns), but can be as high as tens of megahertz (MHz). The OCP circuit in the prior art cannot respond to such rapid transient overcurrents in time, so that repeated peak currents can accumulate stress in the device, and further damage to the MOS transistor or shortening of the service life of the device is caused. Therefore, a new OCP architecture capable of performing time statistics and energy accumulation determination for ac transient overcurrents is needed. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a counting type overcurrent protection circuit and a protection method for AC overcurrent detection, which can count time and judge energy accumulation aiming at AC transient overcurrent, remarkably improve the reliability of a system, better protect devices and prolong the service life of the devices. In order to achieve the above purpose, the invention provides a counting type overcurrent protection circuit for detecting alternating current and overcurrent, which comprises a current detection module, wherein the current detection module is used for outputting detection current and generating corresponding voltage signals, the output end of the current detection module is connected with the positive input end of a high-speed comparator, the voltage signals are connected with the positive input end of the high-speed comparator, the negative input end of the high-speed comparator is connected with reference voltage, the high-speed comparator is used for comparing voltage signals generated by the current detection module with the reference voltage, if the duration of the voltage signals exceeding the reference voltage is greater than a first threshold value, the high-speed comparator outputs high level, the output end of the current detection module is also connected with a reset module, the input end of the reset module is connected with the output end of the high-speed comparator, the reset module is used for detecting overcurrent time, if the duration of the detection overcurrent exceeds a second threshold value, the high-speed comparator is output to reset the current detection module, the output high level is connected with a counter module, the output of the counter module is connected with a period control module, the output of the counter module is connected with an overcurrent protection logic module, the period control module is used for resetting the counter module when the period is finished, the counter module is reset, and the count value reaches the threshold value of the logic after the counter module is reset, and the counter logic module is reset after the counter module reaches the threshold value and the counter logic value is triggered, the counter logic is reset after the counter logic module reaches the counter logic and the counter logic module is triggered. Further, the current detection module comprises a current detection circuit and a resistor RS, a first output end of the current detection circuit is connected with one end of the resistor RS, the other end of the resistor RS is connected with GND, and a second output end of the current detection circuit is respectively connected with a positive input end of the high-speed comparator and the reset module. Further, the reset module comprises a duration time judging circuit and an NMOS reset tube, the drain electrode of the NMOS reset tube is connected with the second output end of the current detection circuit, the source electrode of the NMOS reset tube is connected with GND, the grid electrode of the NMOS reset tube is connected with the output end of the duration time judging circuit, and the input end of the duration time judging circuit is connected with the output end of the high-speed comparator. Further, the duration time judging circuit comprises a rising edge delay module and a logic AND gate, a first path of an output signal of the high-speed comparator enters the rising edge delay module and is input into a first input end of the logic AND gate after delay, a second path of the output signal of the high-speed comparator enters a second input end of the logic AND gate, and the output of the logic AND gate is connected with a grid electrode of the NMOS reset tube