An overcurrent protection device

Abstract

The present application provides an overcurrent protection device, which relates to the field of electronic power design. The device includes: an overcurrent detection unit, a threshold comparison unit, and a latch feedback control unit; the overcurrent detection unit is connected to the threshold comparison unit; the threshold comparison unit is connected to the latch feedback control unit; the latch feedback control unit is connected to the overcurrent detection unit; the overcurrent detection unit is used to monitor the load's current usage data in real time; the threshold comparison unit is used to compare the current usage data with a preset circuit initial threshold, generate a feedback signal for latching; the latch feedback control unit is used to control the on and off of the load through the feedback signal. The overcurrent protection circuit of the present invention can flexibly adjust the overcurrent threshold according to the specific needs of the user and has a strong load-carrying capacity.

Description

Technical Field

[0001] The present application relates to the field of electronic power design, and in particular to an overcurrent protection device. Background Art

[0002] In electronic components such as semiconductor devices and chips, overcurrent conditions can cause the heat generated by electronic components to rise significantly, and may also cause failure or damage. In the traditional electronic power field and the mainstream circuits on the market, overcurrent protection solutions use external resistors or built-in fuses or discrete op amps for overcurrent protection, which have slow response speeds and low accuracy. The existing new high-side drive switches are expensive, and most of the overcurrent thresholds cannot be adjusted, which has large limitations and low cost-effectiveness. Summary of the invention

[0003] The purpose of the present invention is to provide an overcurrent protection device in order to solve the problems of complex circuits and low cost-effectiveness of existing overcurrent protection devices.

[0004] The above-mentioned purpose of the present application is achieved through the following technical solutions: The device comprises: an overcurrent detection unit, a threshold comparison unit, and a latch feedback control unit; the overcurrent detection unit is connected to the threshold comparison unit; the threshold comparison unit is connected to the latch feedback control unit; the latch feedback control unit is connected to the overcurrent detection unit; The overcurrent detection unit is used to monitor the current usage data of the load in real time; The threshold comparison unit is used to compare the current data with the preset circuit initial threshold value, and generate a feedback signal for latching; The latch feedback control unit is used to control the on and off of the load through a feedback signal.

[0005] Optionally, the overcurrent detection unit includes: a resistor R1, a resistor R2, a capacitor C3, a Hall current sensor U1 and a power terminal B+.

[0006] Optionally, pin 1 and pin 2 of the Hall current sensor U1 are connected to power terminal B+; Pin 7 of the Hall current sensor U1 is connected to one end of the resistor R1; The other end of the resistor R1 is connected to one end of the resistor R2; The other end of the resistor R1 is connected to one end of the capacitor C3; The other end of the capacitor C3 and the other end of the resistor R2 are grounded.

[0007] Optionally, the threshold comparison unit includes: a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a 5V power supply terminal, a diode D1 and a bidirectional comparator U13.

[0008] Optionally, pin 2 of the bidirectional comparator U13 is connected to the other end of the resistor R1 in the overcurrent detection unit; Pin 3 of the bidirectional comparator U13 is connected to one end of the resistor R4, and the other end of the resistor R4 is grounded; Pin 3 of the bidirectional comparator U13 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the 5V power supply terminal; Pin 1 of the bidirectional comparator U13 is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to a 5V power supply terminal; Pin 1 of the bidirectional comparator U13 is connected to one end of the resistor R6, and the other end of the resistor R6 is connected to pin 5 of the bidirectional comparator U13; Pin 5 of the bidirectional comparator U13 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to the 5V power supply terminal; Pin 7 of the bidirectional comparator U13 is connected to the cathode of the diode D1; Pin 6 of the bidirectional comparator U13 is connected to one end of the resistor R7, and the other end of the resistor R7 is grounded; Pin 6 of the bidirectional comparator U13 is connected to one end of the resistor R8; Pin 4 of the bidirectional comparator U13 is grounded.

[0009] Optionally, the latch feedback control unit includes: a resistor R10, a resistor R11, a resistor R12, a resistor R13, a diode D2, a voltage regulator diode V2, a TVS diode V1, a P-MOS tube Q1, an N-MOS tube Q2, a DEF terminal, an EN terminal and an OUT terminal.

[0010] Optionally, the resistor R8 in the threshold comparison unit is connected to the EN terminal; Pin 7 of the bidirectional comparator U13 in the threshold comparison unit is connected to the DEF terminal; One end of the resistor R11 is grounded, and the other end is connected to the EN terminal; One end of the resistor R10 is connected to the EN terminal, and the other end is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the DEF terminal; Pin 1 of the N-MOS tube Q2 is connected to the anode of the diode D2, pin 2 is grounded, and pin 3 is connected to one end of the resistor R12; The other end of the resistor R12 is connected to pin 1 of the P-MOS tube Q1; Pin 2 of the P-MOS tube Q1 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to pin 1 of the N-MOS tube Q2; The cathode of the voltage stabilizing diode V2 is connected to the pin 2 of the MOS tube Q1, and the anode is connected to the pin 1 of the MOS tube Q1; Pin 2 of the MOS tube Q1 is connected to pins 3 and 4 of the Hall current sensor U1 in the overcurrent detection unit; Pin 3 of MOS tube Q1 is connected to the OUT terminal; Pin 1 of TVS diode V1 is connected to OUT terminal, and pin 2 is grounded; The Hall current sensor U1 adopts the CC6902S0-30A model; The bidirectional comparator U13 adopts the LM2903XK model; The P-MOS tube Q1 adopts the NCE6082AK model; The N-MOS tube Q2 adopts the L2N7002KLT1G model.

[0011] An overcurrent protection method, the method comprising: Get the current data of the load; Determine whether the current data is greater than a preset current threshold; if it is greater than the preset current threshold, output an overcurrent fault feedback signal, and control the load to disconnect the power supply through the overcurrent fault feedback signal to achieve overcurrent protection of the load.

[0012] The beneficial effects of the technical solution provided by this application are: Overcurrent protection for the power load is achieved through the Hall current sensor and the comparator. The circuit design is simple, the circuit reliability is high, the precision is high, it has a strong load capacity and the overcurrent threshold can be flexibly adjusted. It can be widely used in high-side drive circuits, solving the problem of complex circuits and low cost-effectiveness of existing overcurrent protection devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present application will be further described below with reference to the accompanying drawings and embodiments, in which: Figure 1 It is a circuit schematic diagram in an embodiment of the present application. DETAILED DESCRIPTION

[0014] In order to have a clearer understanding of the technical features, purposes and effects of the present application, the specific implementation methods of the present application are now described in detail with reference to the accompanying drawings.

[0015] An embodiment of the present application provides an overcurrent protection device.

[0016] Please refer to Figure 1 , Figure 1It is a circuit schematic diagram of an overcurrent protection device in an embodiment of the present application, comprising: an overcurrent detection unit, a threshold comparison unit, and a latch feedback control unit; the overcurrent detection unit is connected to the threshold comparison unit; the threshold comparison unit is connected to the latch feedback control unit; the latch feedback control unit is connected to the overcurrent detection unit; The overcurrent detection unit is used to monitor the current usage data of the load in real time; The threshold comparison unit is used to compare the current data with the preset circuit initial threshold value, and generate a feedback signal for latching; The latch feedback control unit is used to control the on and off of the load through a feedback signal.

[0017] The present application provides an embodiment as follows: the overcurrent detection unit uses a Hall current sensor to monitor the load current in real time, and its output is connected to the threshold comparison unit. The threshold comparison unit is used for setting the initial threshold of the circuit and for latching and fault feedback after overcurrent. When the system detects that the load current exceeds the current threshold, the system lowers the feedback signal voltage to instruct the control unit to turn off the power supply. The overcurrent protection circuit of the present invention can flexibly adjust the overcurrent threshold according to the specific needs of the user and has a strong load-carrying capacity.

[0018] As an embodiment, in normal operation, the latch feedback control unit will open the switch, and then connect the current sampling unit to the load output, so as to sample the output load current and output the corresponding voltage value of the sampled current. The threshold comparison unit is used for the initial threshold setting of the circuit in the first direction, and is used to compare the voltage value corresponding to the sampled current output by the current sampling unit, and transmit the signal to the next direction when the sampled voltage is greater than the reference voltage, and transmit the feedback signal to the latch feedback control unit in the second direction. The latch feedback control unit is respectively connected to the threshold comparison unit and the output load, and shuts down the circuit upon receiving the overcurrent feedback signal from the threshold comparison unit.

[0019] The overcurrent detection unit includes: a resistor R1, a resistor R2, a capacitor C3, a Hall current sensor U1 and a power terminal B+.

[0020] Pin 1 and pin 2 of the Hall current sensor U1 are connected to the power terminal B+; Pin 7 of the Hall current sensor U1 is connected to one end of the resistor R1; The other end of the resistor R1 is connected to one end of the resistor R2; The other end of the resistor R1 is connected to one end of the capacitor C3; The other end of the capacitor C3 and the other end of the resistor R2 are grounded.

[0021] The threshold comparison unit includes: a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a 5V power supply terminal, a diode D1 and a bidirectional comparator U13.

[0022] Pin 2 of the bidirectional comparator U13 is connected to the other end of the resistor R1 in the overcurrent detection unit; Pin 3 of the bidirectional comparator U13 is connected to one end of the resistor R4, and the other end of the resistor R4 is grounded; Pin 3 of the bidirectional comparator U13 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the 5V power supply terminal; Pin 1 of the bidirectional comparator U13 is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to a 5V power supply terminal; Pin 1 of the bidirectional comparator U13 is connected to one end of the resistor R6, and the other end of the resistor R6 is connected to pin 5 of the bidirectional comparator U13; Pin 5 of the bidirectional comparator U13 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to the 5V power supply terminal; Pin 7 of the bidirectional comparator U13 is connected to the cathode of the diode D1; Pin 6 of the bidirectional comparator U13 is connected to one end of the resistor R7, and the other end of the resistor R7 is grounded; Pin 6 of the bidirectional comparator U13 is connected to one end of the resistor R8; Pin 4 of the bidirectional comparator U13 is grounded.

[0023] The latch feedback control unit includes: a resistor R10, a resistor R11, a resistor R12, a resistor R13, a diode D2, a voltage regulator diode V2, a TVS diode V1, a P-MOS transistor Q1, an N-MOS transistor Q2, a DEF terminal, an EN terminal and an OUT terminal.

[0024] The resistor R8 in the threshold comparison unit is connected to the EN terminal; Pin 7 of the bidirectional comparator U13 in the threshold comparison unit is connected to the DEF terminal; One end of the resistor R11 is grounded, and the other end is connected to the EN terminal; One end of the resistor R10 is connected to the EN terminal, and the other end is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the DEF terminal; Pin 1 of the N-MOS tube Q2 is connected to the anode of the diode D2, pin 2 is grounded, and pin 3 is connected to one end of the resistor R12; The other end of the resistor R12 is connected to pin 1 of the P-MOS tube Q1; Pin 2 of the P-MOS tube Q1 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to pin 1 of the N-MOS tube Q2; The cathode of the voltage stabilizing diode V2 is connected to the pin 2 of the MOS tube Q1, and the anode is connected to the pin 1 of the MOS tube Q1; Pin 2 of the MOS tube Q1 is connected to pins 3 and 4 of the Hall current sensor U1 in the overcurrent detection unit; Pin 3 of MOS tube Q1 is connected to the OUT terminal; Pin 1 of TVS diode V1 is connected to OUT terminal, and pin 2 is grounded; The Hall current sensor U1 adopts the CC6902S0-30A model; The bidirectional comparator U13 adopts the LM2903XK model; The P-MOS tube Q1 adopts the NCE6082AK model; The N-MOS tube Q2 adopts the L2N7002KLT1G model.

[0025] An overcurrent protection method, the method comprising: Get the current data of the load; Determine whether the current data is greater than a preset current threshold; if it is greater than the preset current threshold, output an overcurrent fault feedback signal, and control the load to disconnect the power supply through the overcurrent fault feedback signal to achieve overcurrent protection of the load.

[0026] As an embodiment, the working principle of the present invention is: shut down the control EN output high, so that the gate voltage of the field effect tube Q2 rises, the source and drain are turned on, the gate of the field effect tube Q1 is grounded, the source and drain are turned on, and the circuit starts to work normally. At this time, the Hall current sensor U1 starts to detect the current. The resistance ratio of the resistor R3 and the resistor R4 is set in the threshold comparison unit to adjust the voltage value of +INA to change the overcurrent threshold. The static output of the Hall current sensor is 2.5V. For every 1A increase in load current, the OUT voltage of the Hall current sensor increases by 67mV. Therefore, the resistance ratio of the resistor R3 pull-up power supply 5V cannot be lower than 1:1. R3=10K, R4=20K, the overcurrent threshold is:

[0027]

[0028] When the output current When the current is greater than 12.39A, the voltage of the bidirectional comparator -INA connected to the OUT pin of the Hall current sensor U1 is greater than +INA; after two comparisons by the bidirectional comparator U13, the OUTB pin outputs an overcurrent fault feedback signal DET. Indicates input current; Indicates the maximum current.

[0029] After two comparisons by the bidirectional comparator U13, OUTB outputs an overcurrent fault feedback signal DET, and the feedback latch unit latches the fault alarm signal.

[0030] As an embodiment, the current sensing to voltage rise time of the Hall current sensor U1 of the present invention can reach the voltage sampling pin OUT within 2us, and the response time of the ordinary current sensor is 10~20ms, and the accuracy is 67mv / 1A. The time from the comparison result at both ends of the bidirectional comparator LM2903 to the output response is 3us. When the sampling voltage exceeds the set threshold voltage, the overcurrent protection condition is reached. The on-state internal resistance of the PMOS tube Q1 is 13mΩ, and td(on) can reach 18ns.

[0031] As an embodiment, the current sampling unit of the present invention can adjust the delay time through the RC circuit composed of capacitor C3 and resistor R1, and adjust the overcurrent protection threshold by changing the threshold comparison unit resistors R3 and R4. All electronic components are packaged in chip form, and the parameters can be flexibly adjusted according to different application scenarios, with a wide range of application types.

[0032] The above are only exemplary embodiments of the present disclosure and cannot be used to limit the scope of the present disclosure. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure.

[0033] This application is intended to cover any variation, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the art not described in the present disclosure. The description and examples are to be regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

Claims

1. An overcurrent protection device, characterized in that: The device comprises: an overcurrent detection unit, a threshold comparison unit, and a latch feedback control unit; the overcurrent detection unit is connected to the threshold comparison unit; the threshold comparison unit is connected to the latch feedback control unit; the latch feedback control unit is connected to the overcurrent detection unit; The overcurrent detection unit is used to monitor the current usage data of the load in real time; The threshold comparison unit is used to compare the current data with the preset circuit initial threshold value, and generate a feedback signal for latching; The latch feedback control unit is used to control the on and off of the load through a feedback signal.

2. An overcurrent protection device as claimed in claim 1, characterized in that: The overcurrent detection unit includes: a resistor R1, a resistor R2, a capacitor C3, a Hall current sensor U1 and a power terminal B+.

3. An overcurrent protection device as claimed in claim 2, characterized in that: Pin 1 and pin 2 of the Hall current sensor U1 are connected to the power terminal B+; Pin 7 of the Hall current sensor U1 is connected to one end of the resistor R1; The other end of the resistor R1 is connected to one end of the resistor R2; The other end of the resistor R1 is connected to one end of the capacitor C3; The other end of the capacitor C3 and the other end of the resistor R2 are grounded.

4. An overcurrent protection device as claimed in claim 2, characterized in that: The threshold comparison unit includes: a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a 5V power supply terminal, a diode D1 and a bidirectional comparator U13.

5. An overcurrent protection device as claimed in claim 4, characterized in that: Pin 2 of the bidirectional comparator U13 is connected to the other end of the resistor R1 in the overcurrent detection unit; Pin 3 of the bidirectional comparator U13 is connected to one end of the resistor R4, and the other end of the resistor R4 is grounded; Pin 3 of the bidirectional comparator U13 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the 5V power supply terminal; Pin 1 of the bidirectional comparator U13 is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to a 5V power supply terminal; Pin 1 of the bidirectional comparator U13 is connected to one end of the resistor R6, and the other end of the resistor R6 is connected to pin 5 of the bidirectional comparator U13; Pin 5 of the bidirectional comparator U13 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to the 5V power supply terminal; Pin 7 of the bidirectional comparator U13 is connected to the cathode of the diode D1; Pin 6 of the bidirectional comparator U13 is connected to one end of the resistor R7, and the other end of the resistor R7 is grounded; Pin 6 of the bidirectional comparator U13 is connected to one end of the resistor R8; Pin 4 of the bidirectional comparator U13 is grounded.

6. An overcurrent protection device as claimed in claim 4, characterized in that: The latch feedback control unit includes: a resistor R10, a resistor R11, a resistor R12, a resistor R13, a diode D2, a voltage regulator diode V2, a TVS diode V1, a P-MOS transistor Q1, an N-MOS transistor Q2, a DEF terminal, an EN terminal and an OUT terminal.

7. An overcurrent protection device as claimed in claim 6, characterized in that: The resistor R8 in the threshold comparison unit is connected to the EN terminal; Pin 7 of the bidirectional comparator U13 in the threshold comparison unit is connected to the DEF terminal; One end of the resistor R11 is grounded, and the other end is connected to the EN terminal; One end of the resistor R10 is connected to the EN terminal, and the other end is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the DEF terminal; Pin 1 of the N-MOS tube Q2 is connected to the anode of the diode D2, pin 2 is grounded, and pin 3 is connected to one end of the resistor R12; The other end of the resistor R12 is connected to pin 1 of the P-MOS tube Q1; Pin 2 of the P-MOS tube Q1 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to pin 1 of the N-MOS tube Q2; The cathode of the voltage stabilizing diode V2 is connected to the pin 2 of the MOS tube Q1, and the anode is connected to the pin 1 of the MOS tube Q1; Pin 2 of the MOS tube Q1 is connected to pins 3 and 4 of the Hall current sensor U1 in the overcurrent detection unit; Pin 3 of MOS tube Q1 is connected to the OUT terminal; Pin 1 of TVS diode V1 is connected to OUT terminal, and pin 2 is grounded; The Hall current sensor U1 adopts the CC6902S0-30A model; The bidirectional comparator U13 adopts the LM2903XK model; The P-MOS tube Q1 adopts the NCE6082AK model; The N-MOS tube Q2 adopts the L2N7002KLT1G model.

8. An overcurrent protection method, implemented based on an overcurrent protection device according to any one of claims 1 to 7, characterized in that: The method comprises: Get the current data of the load; Determine whether the current data is greater than a preset current threshold; if it is greater than the preset current threshold, output an overcurrent fault feedback signal, and control the load to disconnect the power supply through the overcurrent fault feedback signal to achieve overcurrent protection of the load.

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