CN216819370U - Protection circuit and electronic device - Google Patents
Protection circuit and electronic device Download PDFInfo
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- CN216819370U CN216819370U CN202123391336.XU CN202123391336U CN216819370U CN 216819370 U CN216819370 U CN 216819370U CN 202123391336 U CN202123391336 U CN 202123391336U CN 216819370 U CN216819370 U CN 216819370U
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Abstract
The application is applicable to the technical field of electronic circuits, and provides a protection circuit and electronic equipment, wherein the protection circuit is used for protecting a target circuit; the protection circuit comprises a sampling circuit, a comparison circuit and a detection circuit; the sampling circuit is used for sampling a target parameter of the target circuit and outputting a sampling value; the comparison circuit is connected with the sampling circuit and used for outputting a turn-off signal when a sampling value is greater than or equal to a first reference value; the turn-off signal is used for controlling the target circuit to be turned off; the first end of the detection circuit is connected between the sampling circuit and the comparison circuit, and the second end of the detection circuit is used for being connected with a target circuit; the detection circuit is used for carrying out fault detection on at least one of the sampling circuit and the comparison circuit and outputting a fault signal when a fault is detected; the fault signal is used for controlling the target circuit to be disconnected, so that the target circuit can be protected when the sampling value of the target parameter exceeds the first reference value or any one of the sampling circuit and the comparison circuit fails.
Description
Technical Field
The application belongs to the technical field of electronic circuits, and particularly relates to a protection circuit and an electronic device.
Background
The over-current/short-circuit protection circuit is used for performing over-current protection or short-circuit protection on a circuit, and can quickly turn off the whole circuit when the over-current or short-circuit phenomenon occurs in the circuit, so that the circuit is prevented from being damaged by over-current. However, in practical applications, the overcurrent/short-circuit protection circuit may be abnormal, which results in the failure of its protection function, thereby failing to protect the circuit and easily causing the circuit to be damaged during overcurrent.
SUMMERY OF THE UTILITY MODEL
In view of this, embodiments of the present application provide a protection circuit and an electronic device, so as to solve the technical problem that the protection of the current over-current/short-circuit protection circuit cannot be implemented when the protection function fails.
A first aspect for protecting a target circuit; the protection circuit comprises a sampling circuit, a comparison circuit and a detection circuit;
the sampling circuit is used for sampling a target parameter of the target circuit and outputting a sampling value;
the comparison circuit is connected with the sampling circuit and is used for outputting a turn-off signal when the sampling value is greater than or equal to a first reference value; the turn-off signal is used for controlling the target circuit to be disconnected;
the first end of the detection circuit is connected between the sampling circuit and the comparison circuit, and the second end of the detection circuit is used for being connected with the target circuit; the detection circuit is used for carrying out fault detection on at least one of the sampling circuit and the comparison circuit and outputting a fault signal when a fault is detected; the fault signal is used to control the target circuit to open.
Optionally, the target parameter is a target current; the sampling circuit is used for sampling the target current, converting the target current into a voltage sampling value and outputting the voltage sampling value;
the detection circuit comprises a voltage division unit and a comparison unit; the first end of the voltage division unit is connected between the sampling circuit and the comparison circuit, and the second end of the voltage division unit is connected with the comparison unit; the voltage division unit is used for outputting a voltage detection value after dividing the voltage sampling value output by the sampling circuit; the comparison unit is used for outputting the fault signal when the voltage detection value is larger than or equal to a second reference value.
Optionally, the detection circuit further includes a signal simulation unit and a detection unit; the output end of the signal simulation unit is connected with the second end of the voltage division unit; the signal simulation unit is used for outputting a simulation voltage signal to the comparison circuit through the voltage division unit; the analog voltage signal is a voltage signal with a voltage value higher than the first reference value;
the input end of the detection unit is connected with the output end of the comparison circuit, and the detection unit is used for detecting the output voltage value of the comparison circuit when the signal simulation unit outputs the simulation voltage signal and outputting the fault signal when the output voltage value is smaller than a third reference value.
Optionally, the control circuit is further configured to control the target circuit to be in an open state when at least one of the shutdown signal and the fault signal is received.
Optionally, the voltage dividing unit includes a first resistor, a first capacitor, a first diode and a second diode, a first end of the first resistor is used as a first end of the voltage dividing unit, a second end of the first resistor is used as a second end of the voltage dividing unit, the first end of the first capacitor is connected to the second end of the first resistor, an anode of the first diode is connected to the second end of the first resistor, a cathode of the second diode is connected to the second end of the first resistor, the cathode of the first diode is connected to the power supply, and an anode of the second diode is grounded.
Optionally, the sampling circuit includes a second resistor, a third resistor, a fourth resistor, and a first operational amplifier, a first end of the second resistor is used as a first sampling end of the sampling circuit, a first end of the third resistor is used as a second sampling end of the sampling circuit, the first sampling end of the sampling circuit is used for connecting a low potential end of the target circuit, the second sampling end of the sampling circuit is used for connecting a high potential end of the target circuit, a second end of the second resistor is connected to a non-inverting input end of the first operational amplifier, a second end of the third resistor is connected to an inverting input end of the first operational amplifier, the fourth resistor is connected between the inverting input end and the output end of the first operational amplifier, and an output end of the first operational amplifier is used as an output end of the sampling circuit.
Optionally, the comparison circuit includes a comparator, a fifth resistor, and a third diode; the non-inverting input end of the comparator is used as the first input end of the comparison circuit, the first input end of the comparison circuit is used for being connected with the output end of the sampling circuit, the inverting input end of the comparator is used for receiving the first reference value, the output end of the comparator is used as the output end of the comparison circuit, the power supply end of the comparator is used for being connected with a second power supply voltage, the ground end of the comparator is grounded, the cathode of the third diode is connected with the non-inverting input end of the comparator, the anode of the third diode is connected with the first end of the fifth resistor, and the second end of the fifth resistor is connected with the output end of the comparator.
Optionally, the circuit further comprises an isolating switch circuit, the isolating switch circuit is connected with the comparison circuit, and the isolating switch circuit is used for isolating the turn-off signal and then outputting the isolated turn-off signal.
Optionally, the switch circuit includes a sixth resistor, a seventh resistor, an eighth resistor, and a first switch tube, a first end of the sixth resistor is used as the input end of the switch circuit, the input end of the switch circuit is connected to the output end of the comparison circuit, a second end of the sixth resistor and a first end of the seventh resistor are connected to the controlled end of the first switch tube, a second end of the seventh resistor and a first conducting end of the first switch tube are both grounded, a first end of the eighth resistor is used for connecting a third power voltage, and a second end of the eighth resistor and a second conducting end of the first switch tube are connected to each other and used as the output end of the switch circuit.
In a second aspect, an embodiment of the present application provides an electronic device, which includes a target circuit and a protection circuit as described in the first aspect or any optional manner of the first aspect.
The protection circuit and the electronic equipment provided by the embodiment of the application have the following beneficial effects:
according to the protection circuit provided by the embodiment of the application, the target parameter of the target circuit is sampled by the sampling circuit and the sampling value is output, and the shutdown signal is output by the comparison circuit when the sampling value is greater than or equal to the first reference value so as to control the target circuit to be disconnected, so that the target circuit can be protected when the sampling value of the target parameter of the target circuit exceeds the first reference value; in addition, at least one of the sampling circuit and the comparison circuit is subjected to fault detection through the detection circuit, and a fault signal is output when any one of the sampling circuit and the comparison circuit has a fault so as to control the disconnection of the target circuit, so that the target circuit can be protected when any one of the sampling circuit and the comparison circuit fails, and the multi-stage protection of the target circuit is realized.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
Fig. 1 is a schematic structural diagram of a protection circuit according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of a protection circuit according to another embodiment of the present application;
fig. 3 is a schematic circuit diagram of a protection circuit according to an embodiment of the present disclosure.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
It is noted that the terminology used in the description of the embodiments of the present application is for the purpose of describing particular embodiments of the present application only and is not intended to be limiting of the present application. In the description of the embodiments of the present application, "/" means "or" unless otherwise specified, for example, a/B may mean a or B; "and/or" herein is merely an associative relationship describing an association, meaning that there may be three relationships, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. The terms "comprising," including, "" having, "and variations thereof mean" including, but not limited to.
The embodiment of the application firstly provides a protection circuit which is used for protecting a target circuit. Fig. 1 is a schematic structural diagram of a protection circuit according to an embodiment of the present disclosure. As shown in fig. 1, the protection circuit includes a sampling circuit 11, a comparison circuit 12, and a detection circuit 13.
The sampling circuit 11 is configured to sample a target parameter of a target circuit and output a sampled value. For example, the target parameter may be a target current, and the sampled value may be a voltage sampled value corresponding to the target current.
The comparison circuit 12 is connected with the sampling circuit 11, and the comparison circuit 12 is used for comparing the sampling value with a first reference value and outputting a turn-off signal when the sampling value is greater than or equal to the first reference value; the shutdown signal is used to control the target circuit to open. The first reference value corresponds to an overcurrent protection threshold value of the target circuit.
For example, the first reference value may be a first voltage reference value corresponding to the overcurrent protection threshold. The comparison circuit 12 can compare the voltage sampling value with the first voltage reference value and output a turn-off signal when the voltage sampling value is greater than or equal to the first voltage reference value, so that overcurrent protection of the target circuit is realized and the circuit is prevented from being damaged by overcurrent.
A first end of the detection circuit 13 is connected between the sampling circuit 11 and the comparison circuit 12, and a second end of the detection circuit 13 is used for being connected with a target circuit; the detection circuit 13 is configured to perform fault detection on at least one of the sampling circuit 11 and the comparison circuit 12, and output a fault signal when detecting that at least one of the sampling circuit 11 and the comparison circuit 12 has a fault; the fault signal is used for controlling the target circuit to be disconnected, so that the target circuit can be protected when any one of the sampling circuit 11 and the comparison circuit 12 fails, and further the target circuit can be protected in multiple stages.
In the embodiment of the present application, a shutdown circuit (not shown) is provided in the target circuit.
In one possible implementation, the comparison circuit 12 may output a shutdown signal to the shutdown circuit when the sampled value is greater than or equal to the first reference value to control the shutdown circuit to disconnect the target circuit. The detection circuit 13 may output a fault signal to the shutdown circuit to control the shutdown circuit to open the target circuit when detecting that at least one of the sampling circuit 11 and the comparison circuit 12 has a fault.
In another possible implementation, as shown in fig. 2, the protection circuit further includes a control circuit 14. The comparison circuit 12 may output a shutdown signal to the control circuit 14 when the sampled value is greater than or equal to the first reference value. The control circuit 14 controls the shutdown circuit to open the target circuit upon receiving the shutdown signal. The detection circuit 13 may output a failure signal to the control circuit 14 when detecting that at least one of the sampling circuit 11 and the comparison circuit 12 has a failure. When receiving the fault signal, the control circuit 14 may control the shutdown circuit to disconnect the target circuit; on the other hand, a fault indication signal can be output. The fault prompt signal is used for prompting a user that at least one of the sampling circuit 11 and the comparison circuit 12 has a fault, so that the user can timely know the fault state of the sampling circuit 11 and the comparison circuit 12.
In a specific application, for example, the control circuit 14 may be connected to a buzzer (not shown), and the control circuit 14 may output a fault notification signal to the buzzer to notify the fault by controlling the buzzer to sound. The control circuit 14 may also be connected to an indicator light (not shown), and the control circuit 14 may output a fault indication signal to the indicator light, so as to indicate the fault by controlling the indicator light to enter a preset state (e.g., an illuminated or flashing state).
In one possible implementation, the shutdown signal and the fault signal may be high level signals. In other embodiments, the shutdown signal and the fault signal may also be low level signals.
In another embodiment of the present application, the sampling circuit 11 is configured to sample a target current of a target circuit and convert the target current into a voltage sampling value for outputting. Based on this, as shown in fig. 2, the detection circuit 13 includes a voltage division unit 131 and a comparison unit 132. A first terminal of the voltage dividing unit 131 is connected between the sampling circuit 11 and the comparing circuit 12, and a second terminal of the voltage dividing unit 131 is connected to the comparing unit 132. The voltage dividing unit 131 is configured to divide the voltage sampling value output by the sampling circuit 11 and output a voltage detection value. The comparison unit 132 is configured to compare the voltage detection value with a second reference value, and output a fault signal when the voltage detection value is greater than or equal to the second reference value.
In this embodiment, when the sampling circuit 11 fails, even if the input end of the sampling circuit 11 has no signal input, the voltage sampling value of the output end is greater than or equal to the preset value, so the second reference value may be determined according to the preset value and the voltage division value of the voltage sampling value by the voltage division unit 131, and specifically, the second reference value may be a difference value between the preset value and the voltage division value. The preset value may be an empirical value, for example, the preset value may be 5 volts.
In this embodiment, whether the voltage sampling value output by the sampling circuit 11 is normal is determined by determining the magnitude relationship between the voltage sampling value and the second reference value, so as to implement fault detection on the sampling circuit 11.
In yet another embodiment of the present application, as shown in fig. 2, the detection circuit 13 further includes a signal simulation unit 133 and a detection unit 134. An output terminal of the signal simulation unit 133 is connected to a second terminal of the voltage division unit 131. The signal simulation unit 133 is configured to output a simulation voltage signal to the comparison circuit 12 through the voltage division unit 131. The analog voltage signal is a voltage signal with a voltage value higher than a first reference value. The analog voltage signal is used to simulate the voltage signal actually output by the sampling circuit 11 under the overcurrent condition.
The input terminal of the detection unit 134 is connected to the output terminal of the comparison circuit 12, and the detection unit 134 is configured to detect the output voltage value of the comparison circuit 12 when the signal simulation unit 133 outputs the analog voltage signal, and output a fault signal when the output voltage value is smaller than the third reference value.
Since the analog voltage signal is a voltage signal having a voltage value higher than the first reference value, when the comparison circuit 12 is normal, the output voltage value thereof is greater than or equal to the third reference value; when the comparison circuit is in fault, the output voltage value is smaller than the third reference value. Therefore, while the signal simulation unit 133 outputs the analog voltage signal to the comparison circuit, the fault state of the comparison circuit 12 can be determined by judging the magnitude relationship between the output voltage value of the comparison circuit 12 and the third reference value, and fault detection of the comparison circuit is realized.
In a specific application, the comparing unit 132, the signal simulating unit 133 and the detecting unit 134 may be integrated with the control circuit 14 in one processor.
In a further embodiment of the application, the protection circuit further comprises an isolating switch circuit 15. The isolator switch circuit 15 is connected to the comparator circuit 12. The isolating switch circuit 15 is configured to isolate the shutdown signal output by the comparison circuit 12 and output the isolated shutdown signal. In this embodiment, the detection circuit 13 may be connected to an output terminal of the isolation switch circuit 15 to detect the isolated turn-off signal.
In one possible implementation, the isolating switch circuit 15 may be connected to the control circuit 14. In order to facilitate signal detection by the control circuit 14, the disconnecting switch circuit 15 may perform level conversion on the shutdown signal output by the comparison circuit 12 to obtain a low level signal after receiving the shutdown signal, and output the low level signal to the control circuit 14. When the control circuit 14 detects the low level signal, it controls the shutdown circuit to open the target circuit.
In yet another embodiment of the present application, the protection circuit further comprises a reference circuit 16. Reference circuit 16 is connected to comparison circuit 12. Reference circuit 16 is used to provide a first reference value to comparison circuit 12, e.g., is used to provide a first voltage reference value to comparison circuit 12.
In a further embodiment of the application, the protection circuit further comprises a first filter circuit 17. A first terminal of the first filter circuit 17 is connected to the output terminal of the sampling circuit 11, and a second terminal of the first filter circuit 17 is connected to a first input terminal of the comparison circuit 12 and a first terminal of the detection circuit 13. The third terminal of the first filter circuit 17 is grounded. The first filter circuit 17 is configured to filter the electric signal output by the sampling circuit 11.
In yet another embodiment of the present application, the protection circuit further comprises a second filter circuit 18. A first terminal of the second filter circuit 18 is connected to the output terminal of the comparator circuit 12, and a second terminal of the second filter circuit 18 is connected to the input terminal of the isolator circuit 15. The third terminal of the second filter circuit 18 is grounded. The second filter circuit 18 is used for filtering the electric signal output by the comparator circuit 12.
Fig. 3 is a schematic circuit diagram of a protection circuit according to an embodiment of the present disclosure. As shown in fig. 3, in an embodiment of the present application, the voltage dividing unit 131 includes a first resistor R1, a first capacitor C1, a first diode D1, and a second diode D2. A first end of the first resistor R1 is used as a first end of the voltage dividing unit 131, a second end of the first resistor R1 is used as a second end of the voltage dividing unit 131, a first end of the first capacitor C1 is connected to a second end of the first resistor R1, a second end of the first capacitor C1 is grounded, an anode of the first diode D1 is connected to a second end of the first resistor R1, a cathode of the second diode D2 is connected to a second end of the first resistor R1, a cathode of the first diode D1 is connected to the first power voltage VDD1, and an anode of the second diode D2 is grounded.
In this embodiment, the voltage dividing value of the voltage dividing unit 11 for the voltage sampling value is a voltage drop across the first resistor R1, that is, a difference value between the voltage sampling value output by the sampling circuit 11 and the voltage detection value output by the voltage dividing unit 131 is a voltage drop across the first resistor R1.
In this embodiment, the first capacitor C1 is disposed at the second end of the first resistor R1 to filter noise at the second end of the first resistor R1, so that the accuracy of the voltage detection value can be improved, and the accuracy of the comparing unit 132 in detecting the fault of the sampling circuit 11 can be improved.
The voltage detection value is stabilized by arranging the voltage stabilizing circuit composed of the first diode D1 and the second diode D2 at the second end of the first resistor R1, so that the voltage detection value can be more accurate, and the accuracy of the comparison unit 132 in detecting the fault of the sampling circuit 11 is further improved.
In another embodiment of the present application, the sampling circuit 11 may be a differential sampling circuit, and the sampling circuit 11 includes a first sampling terminal and a second sampling terminal, the first sampling terminal is used for connecting to the low potential terminal Cur ″ of the target circuit, and the second sampling terminal is used for connecting to the high potential terminal Cur + of the target circuit. Specifically, the sampling circuit 11 includes a second resistor R2, a third resistor R3, a fourth resistor R4, and a first operational amplifier U1. The first end of the second resistor R2 is used as the first sampling end of the sampling circuit 11, the first end of the third resistor R3 is used as the second sampling end of the sampling circuit 11, the second end of the second resistor R2 is connected to the noninverting input end INT1+ of the first operational amplifier U1, the second end of the third resistor R3 is connected to the inverting input end INT 1-of the first operational amplifier U1, the fourth resistor R4 is connected between the inverting input end INT 1-and the output end Vout1 of the first operational amplifier U1, and the output end Vout1 of the first operational amplifier U1 is used as the output end of the sampling circuit 11.
In this embodiment, when the target circuit is over-current or short-circuit, the voltage value of the output terminal Vout1 of the first operational amplifier U1 is greater than or equal to the first reference value.
In another embodiment of the present application, the comparison circuit 12 includes a comparator U2, a fifth resistor R5, and a third diode D3. A non-inverting input terminal INT2+ of the comparator U2 is used as a first input terminal of the comparator circuit 12, the first input terminal of the comparator circuit 12 is used for connecting an input terminal of the sampling circuit 11, an inverting input terminal INT 2-of the comparator U2 is used for receiving a first reference value, an output terminal Vout2 of the comparator U2 is used as an output terminal of the comparator circuit 12, a power supply terminal of the comparator U2 is used for connecting a second power supply voltage VDD2, a ground terminal of the comparator U2 is grounded, a cathode of the third diode D3 is connected to a non-inverting input terminal INT2+ of the comparator U1, an anode of the third diode D3 is connected to a first terminal of the fifth resistor R5, and a second terminal of the fifth resistor R5 is connected to an output terminal Vout2 of the comparator U2.
In this embodiment, the comparator U2 is configured to compare the voltage value of the output terminal Vout1 of the first operational amplifier U1 with a first reference value, and output a high level signal when the voltage value of the output terminal Vout1 of the first operational amplifier U1 is greater than the first reference value, where the high level signal is a shutdown signal.
In this embodiment, the output terminal Vout2 of the comparator U2 is connected to the non-inverting input terminal INT2+ of the comparator U2 through the fifth resistor R5 and the third diode D3, so that it can be ensured that the output terminal Vout2 and the non-inverting input terminal INT2+ of the comparator U2 are always high-level signals when the target circuit is subjected to an overcurrent or short-circuit phenomenon, and further ensured that the target circuit is always in an off state when the target circuit is subjected to the overcurrent or short-circuit phenomenon, thereby implementing overcurrent or short-circuit protection on the target circuit.
In another embodiment of the present application, the isolation switch circuit 15 includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a first switch transistor Q1. A first end of the sixth resistor R6 is used as an input end of the isolating switch circuit 15, an input end of the isolating switch circuit 15 is connected to an output end of the comparison circuit 12, a second end of the sixth resistor R6 and a first end of the seventh resistor R7 are commonly connected to a controlled end of the first switch tube Q1, a second end of the seventh resistor R7 and a first conducting end of the first switch tube Q1 are both grounded, a first end of the eighth resistor R8 is used for connecting the third power voltage VDD3, and a second end of the eighth resistor R8 and a second conducting end of the first switch tube Q1 are commonly connected and used as an output end of the isolating switch circuit 15.
Illustratively, the first switch Q1 may be an NPN transistor. The base of the NPN transistor may serve as the controlled terminal of the first switch Q1, the emitter of the NPN transistor may serve as the first conducting terminal of the first switch Q1, and the collector of the NPN transistor may serve as the second conducting terminal of the first switch Q1. Based on this, when the comparator U2 outputs a high level signal, the NPN transistor is turned on, so that the switching circuit 16 outputs a low level signal. Based on this, when the comparator U2 outputs a high level signal (i.e., an off signal), the first switch tube Q1 is turned on, and at this time, the output end of the isolating switch circuit 15 outputs a low level signal, thereby implementing level conversion of the off signal.
In yet another embodiment of the present application, the reference circuit 16 may include a ninth resistor R9, a tenth resistor R10, and a second capacitor C2. A first end of the ninth resistor R9 is used for receiving the reference voltage REF, a second end of the ninth resistor R9 is used as an output end of the reference circuit 16, an output end of the reference circuit 16 is used for being connected to the inverting input end INT2 of the comparator U2, a first end of the tenth resistor R10 is connected to a second end of the ninth resistor R9, a first end of the second capacitor C2 is connected to a second end of the ninth resistor R9, and a second end of the tenth resistor R10 and a second end of the second capacitor C2 are both grounded.
In this embodiment, the ninth resistor R9 divides the reference voltage REF and outputs the first reference value to the inverting input terminal INT 2-of the comparator U2.
In yet another embodiment of the present application, the first filter circuit 17 may include an eleventh resistor R11 and a third capacitor C3. A first terminal of the eleventh resistor R11 is used as a first terminal of the first filter circuit 17, a second terminal of the eleventh resistor R11 is connected to the first terminal of the third capacitor C3 and is used as a second terminal of the first filter circuit 17, and a second terminal of the third capacitor C3 is used as a third terminal of the first filter circuit 17.
In yet another embodiment of the present application, the second filter circuit 18 may include a twelfth resistor R12 and a fourth capacitor C4. A first terminal of the twelfth resistor R12 is used as a first terminal of the second filter circuit 18, a second terminal of the twelfth resistor R12 is connected to the first terminal of the fourth capacitor C4 and is used as a second terminal of the second filter circuit 18, and a second terminal of the fourth capacitor C4 is used as a third terminal of the second filter circuit 18.
The protection circuit of this embodiment is further described with reference to fig. 3:
firstly, the sampling circuit 11 and the comparison circuit 12 can perform overcurrent protection on the target circuit, so that when the target circuit is subjected to overcurrent or short circuit, a shutdown signal is timely output to control the target circuit to be shut down.
Secondly, a detection circuit 13 is further arranged in the embodiment, and the detection circuit 13 can realize fault detection on the sampling circuit 11 and the comparison circuit 12 when the target circuit is not started, so that the sampling circuit 11 and the comparison circuit 12 are ensured to work normally in the running process of the target circuit, and secondary protection on the target circuit is realized. Specifically, the detection circuit 13 may sample the voltage at the output terminal of the sampling circuit 11. Since the sampling circuit 11 employs a differential sampling circuit that outputs a voltage of 0 when there is no input, it can be determined that there is a failure in the sampling circuit 11 when it is detected that the voltage output from the sampling circuit 11 is higher than 0, or higher than a certain threshold value. For example, when it is detected that the voltage output by the sampling circuit 11 is 5 volts, it may be determined that there is a fault, and the comparing unit 132 outputs a fault signal to shut down the target circuit, so as to prevent the target circuit from being started when the sampling circuit 11 is abnormal.
The detection circuit 13 may further output an analog voltage signal to an input terminal of the comparison circuit 12, so as to simulate a voltage signal actually output by the sampling circuit 11 when the target circuit is over-current, thereby detecting whether the comparison circuit 12 can normally output a shutdown signal, if not, indicating that a fault exists, and outputting a fault signal to shut down the target circuit, so as to avoid the target circuit being started when the comparison circuit 12 is abnormal.
The embodiment of the present application further provides an electronic device, which may include a target circuit and the protection circuit in any embodiment corresponding to fig. 1 to 3.
In one embodiment, the electronic device may be an energy storage device for storing electrical energy to power other devices when needed.
In other embodiments, the electronic device may also be other electric devices that need overcurrent protection.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.
Claims (10)
1. A protection circuit for protecting a target circuit; the protection circuit comprises a sampling circuit, a comparison circuit and a detection circuit;
the sampling circuit is used for sampling a target parameter of the target circuit and outputting a sampling value;
the comparison circuit is connected with the sampling circuit and is used for outputting a turn-off signal when the sampling value is greater than or equal to a first reference value; the turn-off signal is used for controlling the target circuit to be disconnected;
the first end of the detection circuit is connected between the sampling circuit and the comparison circuit, and the second end of the detection circuit is used for being connected with the target circuit; the detection circuit is used for carrying out fault detection on at least one of the sampling circuit and the comparison circuit and outputting a fault signal when a fault is detected; the fault signal is used to control the target circuit to open.
2. The protection circuit of claim 1, wherein the target parameter is a target current; the sampling circuit is used for sampling the target current, converting the target current into a voltage sampling value and outputting the voltage sampling value;
the detection circuit comprises a voltage division unit and a comparison unit; the first end of the voltage division unit is connected between the sampling circuit and the comparison circuit, and the second end of the voltage division unit is connected with the comparison unit; the voltage division unit is used for outputting a voltage detection value after dividing the voltage sampling value output by the sampling circuit; the comparison unit is used for outputting the fault signal when the voltage detection value is larger than or equal to a second reference value.
3. The protection circuit of claim 2, wherein the detection circuit further comprises a signal simulation unit and a detection unit; the output end of the signal simulation unit is connected with the second end of the voltage division unit; the signal simulation unit is used for outputting a simulation voltage signal to the comparison circuit through the voltage division unit; the analog voltage signal is a voltage signal with a voltage value higher than the first reference value;
the input end of the detection unit is connected with the output end of the comparison circuit, and the detection unit is used for detecting the output voltage value of the comparison circuit when the signal simulation unit outputs the simulation voltage signal and outputting the fault signal when the output voltage value is smaller than a third reference value.
4. The protection circuit according to any one of claims 1 to 3, further comprising a control circuit for controlling the target circuit to be in an open state upon receiving at least one of the shutdown signal and the fault signal.
5. The protection circuit according to claim 2, wherein the voltage dividing unit includes a first resistor, a first capacitor, a first diode, and a second diode, a first end of the first resistor is used as a first end of the voltage dividing unit, a second end of the first resistor is used as a second end of the voltage dividing unit, a first end of the first capacitor is connected to a second end of the first resistor, a second end of the first capacitor is grounded, an anode of the first diode is connected to a second end of the first resistor, a cathode of the second diode is connected to a second end of the first resistor, a cathode of the first diode is used for receiving a first power voltage, and an anode of the second diode is grounded.
6. The protection circuit according to any one of claims 1 to 3, wherein the sampling circuit comprises a second resistor, a third resistor, a fourth resistor and a first operational amplifier, a first end of the second resistor is used as a first sampling end of the sampling circuit, a first end of the third resistor is used as a second sampling end of the sampling circuit, the first sampling end of the sampling circuit is used for connecting a low potential end of the target circuit, the second sampling end of the sampling circuit is used for connecting a high potential end of the target circuit, the second end of the second resistor is connected with the non-inverting input end of the first operational amplifier, the second end of the third resistor is connected with the inverting input end of the first operational amplifier, the fourth resistor is connected between the inverting input end and the output end of the first operational amplifier, and the output end of the first operational amplifier is used as the output end of the sampling circuit.
7. The protection circuit according to any one of claims 1 to 3, wherein the comparison circuit comprises a comparator, a fifth resistor and a third diode; the non-inverting input end of the comparator is used as the first input end of the comparison circuit, the first input end of the comparison circuit is used for being connected with the output end of the sampling circuit, the inverting input end of the comparator is used for receiving the first reference value, the output end of the comparator is used as the output end of the comparison circuit, the power supply end of the comparator is used for being connected with a second power supply voltage, the ground end of the comparator is grounded, the cathode of the third diode is connected with the non-inverting input end of the comparator, the anode of the third diode is connected with the first end of the fifth resistor, and the second end of the fifth resistor is connected with the output end of the comparator.
8. The protection circuit according to any one of claims 1 to 3, further comprising an isolation switch circuit, wherein the isolation switch circuit is connected to the comparison circuit, and the isolation switch circuit is configured to isolate the turn-off signal and output the isolated turn-off signal.
9. The protection circuit according to claim 8, wherein the switch circuit includes a sixth resistor, a seventh resistor, an eighth resistor, and a first switch tube, a first end of the sixth resistor serves as an input end of the switch circuit, an input end of the switch circuit is connected to an output end of the comparison circuit, a second end of the sixth resistor and a first end of the seventh resistor are connected to the controlled end of the first switch tube in common, a second end of the seventh resistor and a first conducting end of the first switch tube are both grounded, a first end of the eighth resistor is used for connecting to a third power supply voltage, and a second end of the eighth resistor and a second conducting end of the first switch tube are connected in common and serve as an output end of the switch circuit.
10. An electronic device comprising a target circuit and the protection circuit according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123391336.XU CN216819370U (en) | 2021-12-29 | 2021-12-29 | Protection circuit and electronic device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123391336.XU CN216819370U (en) | 2021-12-29 | 2021-12-29 | Protection circuit and electronic device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216819370U true CN216819370U (en) | 2022-06-24 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202123391336.XU Active CN216819370U (en) | 2021-12-29 | 2021-12-29 | Protection circuit and electronic device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN216819370U (en) |
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2021
- 2021-12-29 CN CN202123391336.XU patent/CN216819370U/en active Active
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