A new over-current shutdown recirculation module and power circuit

Abstract

The application discloses a novel overcurrent shutdown and reclosing module and a power circuit, wherein the overcurrent shutdown and reclosing module can detect the current size in a loop, and when overcurrent occurs, the loop is disconnected, and after a time delay, reclosing is started; if the overcurrent state still exists after reclosing, the loop is continuously disconnected, and after a time delay, reclosing is continuously started, and the cycle is repeated; if the overcurrent state is removed after reclosing, the loop returns to normal power supply, and the following hardware devices are configured: self-locking devices, a current sensor, a comparator, switching devices and a delay trigger circuit. The circuit is simple in form, all the circuits are realized by hardware, a processor and software are not needed, and the anti-interference capability is high.

Description

Technical Field

[0001] This invention relates to a novel overcurrent shutdown cyclic reconnection module and power circuit. The overcurrent shutdown cyclic reconnection module is a novel pure hardware overcurrent shutdown cyclic reconnection module designed with discrete components. Its significant feature is that when applied in a circuit, the product can detect the magnitude of the current in the circuit. When an overcurrent occurs, the product immediately disconnects the circuit, delays for a period of time, and then reconnects. If the overcurrent condition still exists after reconnection, the circuit is disconnected again, and after a period of delay, it reconnects again, repeating the cycle. If the overcurrent condition is resolved after reconnection, the circuit returns to normal power supply. Background Technology

[0002] In a MOSFET operating circuit, it's common to detect the current value within the MOSFET loop. When an overcurrent occurs, the MOSFET is shut down to prevent damage. After a period of time following the overcurrent shutdown, the MOSFET is reconnected. At this point, it's necessary to determine if the overcurrent condition persists in the loop. If the overcurrent condition remains after reconnection, the loop is disconnected again, and after a delay, it is reconnected, repeating this cycle. If the overcurrent condition is resolved after reconnection, the MOSFET is turned on again. In practical applications, a processor is often used to detect overcurrent. When an overcurrent occurs, an internal timer starts counting, and after a delay, the processor issues a reconnection command, continuing to monitor the loop current until the overcurrent is resolved and the MOSFET is turned on again. However, in certain specific situations, to avoid malfunctions caused by electromagnetic interference, it's required to use logic built from discrete components to implement the above functions. Summary of the Invention

[0003] For the specific situations mentioned above, the present invention aims to provide a novel overcurrent shutdown cyclic reconnection module. This module is composed of discrete components, has a simple circuit configuration, is entirely implemented in hardware, requires no processor or software, and has strong anti-interference capabilities.

[0004] To address this, the novel overcurrent shutdown and reconnection module provided by this invention can detect the magnitude of the current in the circuit. When an overcurrent occurs, the circuit is disconnected, and after a delay, reconnection begins. If the overcurrent condition persists after reconnection, the circuit is disconnected again, and after a delay, reconnection continues, repeating this cycle. If the overcurrent condition is resolved after reconnection, the circuit returns to normal power supply. The module is configured with the following hardware components:

[0005] The first switching device is used to connect to the drive circuit of the circuit and disconnect the excitation of the drive circuit when there is an overcurrent in the circuit.

[0006] A current sensor is used to sense the current in a circuit and output a linear voltage value.

[0007] A comparator, configured with a first threshold and a second threshold, flips its first output when the voltage value output by the current sensor exceeds the first threshold, outputting a second state signal. A second switching device generates a first signal when the comparator outputs the second state signal, causing the first switching device to activate and disconnect the drive circuit's excitation, thus breaking the loop.

[0008] The delayed trigger circuit includes a charging capacitor. When the second switching device generates a first signal, the first switching device also connects the charging capacitor to the power supply to charge the charging capacitor. When the voltage on the charging capacitor is greater than a second threshold, the second output of the comparator flips and outputs a second state signal, causing the second switching device to generate a second signal, which restores the first switching device to its initial state, enabling the drive circuit to operate and the loop to function. When the first switching device returns to its initial state, the charging capacitor begins to discharge, causing its voltage to fall below the second threshold, and the second output of the comparator flips.

[0009] In some embodiments, the module provided by the present invention is also configured with a switching power supply for converting a 5V power supply into a 12V power supply.

[0010] In some embodiments, the input terminal of the switching power supply is connected to capacitors C1 and C2, and the output terminal is connected to capacitors C3 and C4.

[0011] In some implementations, the driving circuitry is configured in the module and includes an optocoupler.

[0012] In some embodiments, the first switch includes a first set of contacts, a second set of contacts, and a common terminal. The first set of contacts is configured with a stationary contact A, a stationary contact B serving as an output for connection to a drive circuit of the circuit, and a first actuating element. One end of the first actuating element is fixedly connected to the stationary contact B, and the other end switches from the stationary contact A to the common terminal when the coil is energized. The second set of contacts is configured with a stationary contact C, a stationary contact D connected to the circuit ground, and a second actuating element. One end of the second actuating element is fixedly connected to the stationary contact D, and the other end switches from the common terminal to the stationary contact C when the coil is energized.

[0013] In some implementations, the second switch is a solid-state relay that includes two sets of inputs and outputs.

[0014] In some embodiments, the delayed trigger circuit further includes a charging resistor R1 and a discharging resistor R2.

[0015] Another object of the present invention is to provide a power circuit comprising:

[0016] Power device Q1;

[0017] The driving circuit is used to drive the power device Q1 to turn on and off; and

[0018] The overcurrent protection circuit is used to detect the current in the circuit formed by the power device Q1. When an overcurrent occurs, the circuit is disconnected, and after a delay, it is reconnected. If the overcurrent condition still exists after reconnection, the circuit is disconnected again, and after a delay, it is reconnected again. This process is repeated until the overcurrent condition is resolved after reconnection, at which point the circuit returns to normal power supply.

[0019] The overcurrent protection circuit is a novel overcurrent shutdown and reconnection module provided by this invention.

[0020] In some embodiments, the drive circuit includes a high-speed optocoupler whose output is connected to the control terminal of the power device Q1 via a resistor R7.

[0021] In some embodiments, a resistor R8 is connected in series between the control terminal and the power output terminal of the power device Q1.

[0022] The beneficial effects of this invention include:

[0023] 1) The circuit is simple in form, and the entire circuit is implemented in hardware, without the need for processors and software, and has strong anti-interference ability.

[0024] 2) The judgment logic is composed of discrete components, which has high stability and extremely fast switch control response speed.

[0025] 3) Low cost and small product size. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0027] Figure 1 A block diagram illustrating the working principle of the novel overcurrent shutdown cyclic reconnection module provided by this invention;

[0028] Figure 2 A block diagram illustrating the working principle of the current sensor provided by this invention;

[0029] Figure 3 The driving circuit principle block diagram provided by the present invention;

[0030] Figure 4 This is a block diagram illustrating the timing triggering principle of the delay circuit provided by the present invention.

[0031] Figure 5 A block diagram illustrating the relay self-locking principle is provided for this invention. Detailed Implementation

[0032] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make the invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0033] The module provided by this invention uses a current sensor to detect the current in the circuit and feeds the current value back to the input of the comparator. When an overcurrent occurs, the comparator starts to switch levels to shut down the drive circuit, thereby turning off the circuit. At the same time, a delay trigger circuit is used to delay the circuit. After a certain delay, the comparator is triggered to switch levels to reconnect and make the circuit work. The current in the circuit is detected until the overcurrent is released and normal operation is restored.

[0034] Reference Figures 1-5 The overcurrent shutdown and reconnection module provided by this invention is configured with a self-locking device, a current sensor, a comparator, a switching device, and a delayed trigger circuit. The self-locking device is used to connect to the drive circuit of the loop, cutting off the excitation of the drive circuit control terminal to disconnect the loop when an overcurrent occurs. The self-locking device includes a first set of contacts, a second set of contacts, and a common terminal. The first set of contacts includes a stationary contact A, a stationary contact B (used as an output for connection to the drive circuit of the loop), and a first actuating element. One end of the first actuating element is fixedly connected to the stationary contact B, and the other end switches from the stationary contact A to the common terminal when the coil is energized. The second set of contacts includes a stationary contact C connected to a 5V power supply via resistor R3, a stationary contact D connected to the 5V GND of the circuit, and a second actuating element. One end of the second actuating element is fixedly connected to the stationary contact D, and the other end switches from the common terminal to the stationary contact C when the coil is energized. This self-locking device can directly implement a self-locking circuit using a relay with two sets of switching contacts, such as... Figure 5 As shown, the negative terminal of the control relay coil is high. If the negative terminal of the relay coil is high, the relay does not engage; if the negative terminal of the relay coil is high, the relay coil engages and locks, achieving relay self-locking technology. Alternatively, this self-locking device can also be implemented using two independent relays.

[0035] A current sensor is used to sense the current in a circuit and output a linear voltage value. Current sensors typically employ the Hall effect, sensing the current in the circuit and outputting a linear voltage value. This voltage value shares a common ground with the current sensor's power supply voltage. A 5V power supply powers the current sensor via capacitors C5 and C6. The block diagram of the current sensor's working principle is shown below. Figure 2 As shown.

[0036] The comparator operates as follows: a 5V power supply is provided to the comparator via capacitors C5 and C6. A working voltage threshold is set at the positive input terminal of the comparator (formed by voltage division of the 5V power supply through resistors R10 and R11). The voltage at the negative input terminal is adjustable. When the voltage at the positive input terminal is greater than the voltage at the negative input terminal, the comparator outputs a high level; when the voltage at the positive input terminal is less than the voltage at the negative input terminal, the comparator outputs a low level. The working voltage threshold can be set and adjusted by adjusting the resistance values ​​of resistors R10 and R11. The comparator includes a first positive input terminal, a first inverting input terminal, a second positive input terminal, a second inverting input terminal, a first output, and a second output. The first positive input terminal is configured with the first threshold, and the second positive input terminal is configured with the second threshold. When the voltage value output by the current sensor is greater than the first threshold, the first output of the comparator flips, outputting a first control signal.

[0037] The switching device generates a first signal when the comparator outputs a first control signal, causing the self-locking device to activate and cut off the excitation of the drive circuit control terminal, thus disconnecting the drive circuit and breaking the loop. This switching device can be configured as a dual-channel solid-state relay, or as a dual-channel switch composed of discrete components.

[0038] The delayed trigger circuit includes a charging capacitor C1, a charging resistor R3, and a discharging resistor R4. When the switching device generates the first signal, the self-locking device also causes the power supply to charge the capacitor C1 through the charging resistor R3. The charging capacitor C1 is connected to the second inverting input of the comparator. When the voltage on the charging capacitor C1 is greater than the second threshold, the second output of the comparator flips and outputs a second control signal, causing the switching device to generate a second signal, which restores the self-locking device to its initial state and enables the drive circuit to work, thus activating the loop. At this time, the charging capacitor C1 begins to discharge, causing its voltage to fall below the second threshold, and the second output of the comparator flips.

[0039] The principle of the timed trigger circuit is as follows: a voltage threshold is set at the positive terminal of the comparator, and the capacitor is charged through an RC circuit at the negative terminal of the comparator. When the voltage across the capacitor reaches the voltage threshold, the comparator output flips from high to low. The circuit block diagram is shown below. Figure 4 As shown.

[0040] To improve the applicability of the overcurrent shutdown cycle reconnection module provided by this invention, a drive circuit is configured in the module. This drive circuit is used to turn on and off the power devices in the drive circuit, thereby connecting and disconnecting the circuit. The drive circuit is configured according to the power devices being driven, such as a high-speed optocoupler, but it can also be configured as a general optocoupler.

[0041] Furthermore, the module provided by this invention is configured with a power supply module as a driving source. This power supply module is a switching power supply used to convert 5V power to 12V power. Capacitors C1 and C2 are connected to the input terminal of the switching power supply, and capacitors C3 and C4 are connected to the output terminal. The configuration of the capacitors effectively filters the power supply, ensuring stability and anti-interference capability.

[0042] The overcurrent shutdown and reconnection module provided by this invention, together with a high-speed optocoupler as the driving circuit and a power device Q1, can form a power circuit with overcurrent shutdown and reconnection function. The output of the high-speed optocoupler is connected to the driving terminal of the power device Q1 via a resistor R8, and a resistor R9 is connected in series between the control terminal and the power output terminal of the power device Q1.

[0043] The high-speed optocoupler controls the driving end of the power device Q1, and the driving source is the power module. The high-speed optocoupler controls the driving source to drive the power device Q1 to turn on and off. The current value in the circuit is detected by the current sensor. The dual comparators and dual solid-state relays work together to control the on and off of the relays, thereby realizing the high-speed optocoupler on and off control.

[0044] This invention utilizes an isolated power supply to drive power device Q1, and a high-speed optocoupler to control the switching of the drive power supply. When selecting the drive power supply, it is important to note that excessive drive capability will lead to high EMI generated by power device Q1 during switching, while insufficient drive capability will result in high switching losses of power device Q1. Therefore, the drive capability of the isolated power supply must be appropriately selected. The block diagram of the power device Q1 drive circuit is shown below. Figure 3 As shown.

[0045] In this paper, the power device Q1 is configured as a MOSFET. When an overcurrent occurs in the MOSFET circuit, the comparator flips the output signal to turn off the MOSFET, protecting the load downstream of the MOSFET from overcurrent damage. After turning off the MOSFET, there is a delay before attempting to reconnect the MOSFET. At this time, it is necessary to determine whether the overcurrent condition has been resolved. If the overcurrent condition has been resolved, the MOSFET resumes normal conduction. If the overcurrent condition has not been resolved, the circuit is disconnected again, and after a delay, the circuit is reconnected again. This process is repeated until the overcurrent condition is resolved.

[0046] Combination Figure 5The schematic diagram shown here will be used to further describe the overcurrent shutdown and reconnection module of this invention in more detail. A relay with two sets of switching contacts is used as a self-locking device. The positive and negative terminals of the external on / off control signal are connected to one set of switching contacts of the relay. A resistor R1 is configured between the positive terminal of the on / off control signal and the contact. When the circuit formed by the MOSFET is working normally, the comparator output terminal 1out is high, the first path of the solid-state relay is not conducting, and the negative terminal of the relay coil is floating. Similarly, the comparator output terminal 2out outputs a high level, the positive terminal of the relay coil is 5V, the relay is not energized, the high-speed optocoupler is conducting, the MOSFET is working normally, and the voltage value converted from the induced current value transmitted by the current sensor is compared with the comparator voltage threshold 1. When an overcurrent occurs in the circuit, the voltage value transmitted by the current sensor is greater than the comparator voltage threshold 1, the comparator output 1out is low, the first path of the solid-state relay is conducting, and the negative terminal of the relay coil is connected to 5V GND. Since the positive terminal of the relay coil is... At 5V, the relay starts to engage and lock, the high-speed optocoupler turns off the MOSFET, and the charging circuit starts working. When the charging capacitor reaches the voltage threshold 2, the comparator output 2out is low, the positive terminal of the relay coil is 5VGND, the relay is disconnected again, and the charging capacitor starts to discharge. The comparator output 2out is high, and the positive terminal of the relay coil is 5V. At the same time, the high-speed optocoupler starts to reconnect the MOSFET, and the current sensor continues to transmit the current value. If the overcurrent condition is resolved, as mentioned above, the negative terminal of the relay coil is floating, the relay does not engage, and the MOSFET works normally. If the overcurrent condition still exists, the negative terminal of the relay coil is 5VGND, the relay engages, the MOSFET remains off, the charging capacitor charges again, and the process of checking whether the overcurrent condition is resolved and repeatedly delaying and reconnecting the MOSFET continues until the overcurrent is resolved.

[0047] This disclosure has been described with reference to the foregoing embodiments; however, these embodiments are merely examples for implementing this disclosure. It must be noted that the disclosed embodiments do not limit the scope of this disclosure. On the contrary, any changes and modifications made without departing from the spirit and scope of this disclosure are within the scope of patent protection of this disclosure.

Claims

1. A novel overcurrent shutdown and reconnection module, characterized in that, This module can detect the current in the circuit. When an overcurrent occurs, it disconnects the circuit, delays for a period of time, and then reconnects. If the overcurrent condition persists after reconnection, it disconnects the circuit again, delays for a period of time, and then reconnects again, repeating this cycle. If the overcurrent condition is resolved after reconnection, the circuit returns to normal power supply. It is configured with the following hardware devices: A self-locking device is used to connect to the drive circuit of the circuit. When there is an overcurrent in the circuit, the excitation of the drive circuit control terminal is cut off, the drive circuit is disconnected, and the circuit is disconnected. A current sensor is used to sense the current in a circuit and output a linear voltage value. The comparator is configured with a first threshold and a second threshold. When the voltage value output by the current sensor is greater than the first threshold, the first output of the comparator flips to form a first control signal. A switching device, when the comparator outputs a first control signal, generates a first signal to cause the self-locking device to activate, cutting off the excitation of the drive circuit control terminal, thus disconnecting the drive circuit and breaking the loop; and The delayed trigger circuit includes a charging resistor R3 and a charging capacitor C1. When the switching device generates a first signal, the self-locking device also causes the power supply to start the charging capacitor C1 through the charging resistor R3. When the voltage on the charging capacitor C1 is greater than the second threshold, the second output of the comparator flips and outputs a second control signal, causing the switching device to generate a second signal, which restores the self-locking device to its initial state, enabling the drive circuit to operate and the loop to function. When the self-locking device returns to its initial state, the charging capacitor C1 begins to discharge, causing its voltage to fall below the second threshold, and the second output of the comparator flips. The self-locking device includes a first set of contacts, a second set of contacts, and a common terminal. The first set of contacts is configured with a stationary contact A, a stationary contact B as an output for connection with the drive circuit of the circuit, and a first actuating element. One end of the first actuating element is fixedly connected to the stationary contact B, and the other end is switched from the stationary contact A to the common terminal when the coil is energized. The second set of contacts is configured with a stationary contact C, a stationary contact D connected to the circuit ground, and a second actuator. One end of the second actuator is fixedly connected to the stationary contact D, and the other end is switched from the common terminal to the stationary contact C when the coil is energized.

2. The novel overcurrent shutdown and reconnection module according to claim 1, characterized in that, The switching device is a solid-state relay with two sets of inputs and outputs.

3. The novel overcurrent shutdown and reconnection module according to claim 1, characterized in that, It is also equipped with a switching power supply for converting 5V power to 12V power.

4. The novel overcurrent shutdown and reconnection module according to claim 3, characterized in that, The input terminals of the switching power supply are connected to capacitors C1 and C2, and the output terminals are connected to capacitors C3 and C4.

5. The novel overcurrent shutdown and reconnection module according to claim 1, characterized in that, The driving circuit is configured in the module and includes an optocoupler.

6. A power circuit, characterized in that, The circuit includes: Power device Q1; The driving circuit is used to drive the power device Q1 to turn on and off; and The overcurrent protection circuit is used to detect the current in the circuit formed by the power device Q1. When an overcurrent occurs, the circuit is disconnected, and after a delay, it is reconnected. If the overcurrent condition still exists after reconnection, the circuit is disconnected again, and after a delay, it is reconnected again. This process is repeated until the overcurrent condition is resolved after reconnection, at which point the circuit returns to normal power supply. The overcurrent protection circuit is the novel overcurrent shutdown and reconnection module as described in any one of claims 1-5.

7. The power circuit according to claim 6, characterized in that: The driving circuit includes a high-speed optocoupler, the output of which is connected to the control terminal of the power device Q1 via a resistor R8.

8. The power circuit according to claim 6, characterized in that: A resistor R9 is connected in series between the control terminal and the power output terminal of the power device Q1.

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