Overvoltage protection circuit and device thereof

Abstract

The embodiment of the utility model discloses an overvoltage protection circuit and a device thereof. The circuit comprises a switch unit; the input end of the switch unit is connected with input power; a control unit; the input end of the control unit is connected with a signal source, and the output end of the control unit is connected with the controlled end of the switch unit; a protection unit; the input end of the protection unit is connected with an input power supply. The output end of the protection unit is connected with the controlled end of the switch unit. The switch unit outputs a second voltage in response to a control signal input by the control unit; when the first voltage input by the input power supply is greater than a protection voltage threshold, the protection unit outputs a protection signal to the switch unit, so that the switch unit stops outputting the second voltage. According to the mode, the overvoltage protection circuit composed of the voltage stabilizing diode is arranged on the power supply part, so that the overvoltage protection of the power supply part is realized, a post-stage module is prevented from being damaged by over-high interference voltage input, and the reliability and the safety of the power supply circuit are improved.

Description

Technical Field

[0001] The embodiments of the utility model relate to a field, and in particular to an overvoltage protection circuit and a device thereof. Background Art

[0002] In recent years, wireless chargers have become popular in cars. In-car systems generally use wireless chargers to charge mobile phones. As the charging power increases, the heat generated by wireless chargers also increases. The input power supply in cars is generally 12 or 24V. In order to prevent excessive interference voltage input from damaging the wireless charging module, hardware overvoltage protection is added to the power input part. Utility Model Content

[0003] The main technical problem solved by the embodiments of the utility model is to provide a method for preventing the wireless charging module from being damaged by the impact of excessively high interference voltage.

[0004] In order to solve the above technical problems, a technical solution adopted by the utility model is: to provide an overvoltage protection circuit, comprising: a switch unit; the input end of the switch unit is connected to an input power supply; a control unit; the input end of the control unit is connected to a signal source, and the output end of the control unit is connected to a controlled end of the switch unit; a protection unit; the input end of the protection unit is connected to the input power supply, and the output end of the protection unit is connected to the controlled end of the switch unit; the switch unit outputs a second voltage in response to a control signal input by the control unit; when the first voltage input by the input power supply is greater than a protection voltage threshold, the protection unit outputs a protection signal to the switch unit to stop the switch unit from outputting the second voltage.

[0005] In some embodiments, the input end of the control unit includes a first input end and a second input end, and the signal source includes a first signal source and a second signal source; the first input end of the control unit is connected to the first signal source, and the second input end of the control unit is connected to the second signal source.

[0006] In some embodiments, the switch unit includes a fourth resistor, a sixth resistor, a seventh resistor, a sixteenth resistor, a first switch tube, a second switch tube, a first capacitor and a fourth capacitor; wherein the first end of the fourth resistor is connected to the input power supply, the first end of the sixth resistor and the source of the first switch tube, the second end of the fourth resistor is connected to the gate of the second switch tube, the first end of the sixteenth resistor, the output end of the protection unit and the output end of the control unit, the gate of the first switch tube is connected to the second end of the sixth resistor, the first end of the seventh resistor, the drain of the second switch tube and the first end of the first capacitor, and the drain of the first switch tube is connected to the second end of the first capacitor and the first end of the fourth capacitor as the output end of the switch unit; the source of the second switch tube, the second end of the sixteenth resistor and the second end of the fourth capacitor are grounded.

[0007] In some embodiments, the protection unit includes a first voltage zener diode, an eighth resistor, a thirteenth resistor, a fifteenth resistor, a fourth switch tube and an eighth capacitor; wherein the cathode of the first voltage zener diode is connected to the input power supply and the first end of the eighth capacitor, the anode of the first voltage zener diode is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the first end of the thirteenth resistor and the first end of the fifteenth resistor, the second end of the thirteenth resistor is connected to the base of the fourth switch tube, and the collector of the fourth switch tube is connected to the controlled end of the switch unit; the second end of the eighth capacitor, the second end of the fifteenth resistor and the emitter of the fourth switch tube are grounded.

[0008] In some embodiments, the control unit includes a ninth resistor, a twelfth resistor, a second diode and a fourth diode; wherein the first end of the ninth resistor is connected to the first signal source, the second end of the ninth resistor is connected to the anode of the second diode, and the cathode of the second diode is connected to the cathode of the fourth diode and the controlled end of the switching unit; the first end of the twelfth resistor is connected to the second signal source, and the second end of the twelfth resistor is connected to the anode of the fourth diode.

[0009] In some embodiments, the first signal source is an analog signal source, and the second signal source is a digital signal source.

[0010] In some embodiments, the protection voltage threshold is a voltage regulation value of the first zener diode.

[0011] In some embodiments, a voltage regulation value of the first voltage stabilizing diode is 30V.

[0012] In some embodiments, the control signal is at a high level, and the protection signal is at a low level.

[0013] In order to solve the above technical problem, another technical solution adopted by the present invention is: to provide an overvoltage protection device, including: the overvoltage protection circuit as described above.

[0014] The beneficial effects of the embodiments of the utility model are as follows: different from the prior art, the embodiments of the utility model realize overvoltage protection of the power supply part by setting an overvoltage protection circuit composed of a voltage regulator diode in the power supply part, preventing excessive interference voltage input from damaging the subsequent module, and improving the reliability and safety of the power supply circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of an overvoltage protection circuit provided by an embodiment of the utility model;

[0016] Figure 2 It is a circuit structure diagram of an overvoltage protection circuit provided by an embodiment of the utility model; DETAILED DESCRIPTION

[0017] In order to facilitate the understanding of the utility model, the utility model is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on the other element, or there can be one or more centered elements therebetween. When an element is described as "connected to" another element, it can be directly connected to the other element, or there can be one or more centered elements therebetween. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this specification are for illustrative purposes only.

[0018] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by technicians in the technical field of the present invention. The terms used in this specification are only for the purpose of describing specific embodiments and are not used to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0019] See also Figure 1 , Figure 1 The schematic diagram of the structure of an overvoltage protection circuit is shown, and the overvoltage protection circuit includes a switch unit 110, a control unit 120 and a protection unit 130. The input end of the switch unit 110 is connected to the input power supply 20, the input end of the control unit 120 is connected to the signal source 30, the output end of the control unit 120 is connected to the controlled end of the switch unit 110, the input end of the protection unit 130 is connected to the input power supply 20, and the output end of the protection unit 130 is connected to the controlled end of the switch unit 110.

[0020] Specifically, the control unit 120 outputs a control signal to the switch unit 110 in response to the input signal of the signal source 20; the switch unit 110 includes switching devices such as a switch tube, so that the switch unit 110 turns on the connection between the input end and the output end in response to the control signal output by the control unit 120, and outputs a second voltage according to the first voltage input by the input power supply; the protection unit 130 includes a voltage regulator tube and switching devices such as a switch tube, so that when the first voltage input by the input power supply is greater than the protection voltage threshold, a protection signal is output to the controlled end of the switch unit 110, so that the switch unit 110 disconnects the connection between the input end and the output end, so that the switch unit 110 stops outputting the second voltage.

[0021] In the embodiment of the present application, the protection voltage threshold is the voltage regulation value of the voltage regulator tube in the protection unit.

[0022] In the embodiment of the present application, the control signal is at a high level and the protection signal is at a low level. That is, when the controlled end of the switch unit 110 receives a high-level control signal, the connection between the input end and the output end of the switch unit 110 is turned on; when the controlled end of the switch unit 110 receives a low-level protection signal, the connection between the input end and the output end of the switch unit 110 is turned off.

[0023] In some embodiments, the input end of the control unit 120 includes a first input end and a second input end, and the signal source includes a first signal source and a second signal source. The first input end of the control unit 120 is connected to the first signal source, and the second input end of the control unit 120 is connected to the second signal source.

[0024] In the embodiment of the present application, the first signal source is an analog signal source, and the second signal source is a digital signal source.

[0025] See also Figure 2 , Figure 2 The specific hardware structure of an overvoltage protection circuit provided in an embodiment of the present application is shown.

[0026] The control unit 120 includes a ninth resistor R9, a twelfth resistor R12, a second diode D2 and a fourth diode D4. A first end of the ninth resistor R9 is connected to the first signal source ACC, a second end of the ninth resistor R9 is connected to the anode of the second diode D2, a cathode of the second diode D2 is connected to the cathode of the fourth diode D4 and the controlled end of the switch unit 110; a first end of the twelfth resistor R12 is connected to the second signal source I NH, and a second end of the twelfth resistor R12 is connected to the anode of the fourth diode D4.

[0027] When the first signal source ACC inputs a high-level first signal, or the second signal source I NH inputs a high-level second signal, the controlled end of the switch unit 110 receives a high-level control signal.

[0028] The switch unit 110 includes a fourth resistor R4, a sixth resistor R6, a seventh resistor R7, a sixteenth resistor R16, a first switch tube Q1, a second switch tube Q2, a first capacitor C1 and a fourth capacitor C4.

[0029] A first end of the fourth resistor R is connected to the input power supply VBAT, a first end of the sixth resistor R6 and a source of the first switch tube Q1; a second end of the fourth resistor R4 is connected to a gate of the second switch tube Q2, a first end of the sixteenth resistor R16, an output end of the protection unit 130 and an output end of the control unit 120; a gate of the first switch tube Q1 is connected to a second end of the sixth resistor R6, a first end of the seventh resistor R7, a drain of the second switch tube Q2 and a first end of the first capacitor C1; a drain of the first switch tube Q1 is connected to a second end of the first capacitor C1 and a first end of the fourth capacitor C4 as an output end of the switch unit 110; a source of the second switch tube Q2, a second end of the sixteenth resistor R16 and a second end of the fourth capacitor C4 are grounded GND.

[0030] In the embodiment of the present application, the first switch tube is a P-channel MOS tube, and the second switch tube is an N-channel MOS tube.

[0031] Specifically, the first switch tube Q1 realizes the switching function. When the controlled end of the switch unit 110 receives a high-level control signal, the second switch tube Q2 is turned on, so that the gate level of the first switch tube Q1 is high, and the first switch tube Q1 is turned on to output the second voltage to power the subsequent module.

[0032] The protection unit 130 includes a first voltage zener diode ZD1, an eighth resistor R8, a thirteenth resistor R13, a fifteenth resistor R, a fourth switch tube Q4 and an eighth capacitor C8. The cathode of the first voltage zener diode is connected to the input power supply VBAT and the first end of the eighth capacitor C8, the anode of the first voltage zener diode ZD1 is connected to the first end of the eighth resistor R8, the second end of the eighth resistor R8 is connected to the first end of the thirteenth resistor R13 and the first end of the fifteenth resistor R15, the second end of the thirteenth resistor R13 is connected to the base of the fourth switch tube Q4, and the collector of the fourth switch tube Q4 is connected to the controlled end of the switch unit 110; the second end of the eighth capacitor C8, the second end of the fifteenth resistor R15 and the emitter of the fourth switch tube Q4 are grounded GND.

[0033] In the embodiment of the present application, the fourth switch tube is an NPN transistor.

[0034] When the first voltage input by the input power supply VBAT does not exceed the voltage regulation value of the first voltage zener diode ZD1, the fourth switch tube Q4 cannot be turned on; when the first voltage input by the input power supply VBATT exceeds the voltage regulation value of the first voltage zener diode ZD1, the fourth switch tube Q4 is turned on, thereby pulling down the gate of the second switch tube Q2, so that the second switch tube Q2 is turned off, thereby turning off the first switch tube Q1 to achieve overvoltage protection.

[0035] In some embodiments, the voltage regulation value of the first Zener diode is 30V.

[0036] Based on the overvoltage protection circuit provided in the above-mentioned embodiments, the embodiments of the present application further provide an overvoltage protection device, which includes the overvoltage protection circuit described in the above-mentioned embodiments.

[0037] Different from the prior art, the embodiment of the utility model realizes overvoltage protection of the power supply part by setting an overvoltage protection circuit composed of a voltage regulator diode in the power supply part, prevents excessive interference voltage input from damaging the subsequent module, and improves the reliability and safety of the power supply circuit.

[0038] It should be noted that the preferred embodiments of the utility model are given in the specification and drawings of the utility model, but the utility model can be implemented in many different forms and is not limited to the embodiments described in the specification. These embodiments are not used as additional restrictions on the content of the utility model. The purpose of providing these embodiments is to make the understanding of the disclosure of the utility model more thorough and comprehensive. In addition, the above-mentioned technical features continue to be combined with each other to form various embodiments not listed above, which are all regarded as the scope of the description of the utility model; further, for ordinary technicians in this field, they can be improved or transformed according to the above description, and all these improvements and transformations should belong to the scope of protection of the claims attached to the utility model.

Claims

1. An overvoltage protection circuit, characterized in that: include: Switching unit; The input end of the switch unit is connected to an input power supply; Control unit; The input end of the control unit is connected to a signal source, and the output end of the control unit is connected to a controlled end of the switch unit; Protection unit; The input end of the protection unit is connected to the input power supply, and the output end of the protection unit is connected to the controlled end of the switch unit; The switch unit outputs a second voltage in response to a control signal input by the control unit; When the first voltage input by the input power source is greater than a protection voltage threshold, the protection unit outputs a protection signal to the switch unit, so that the switch unit stops outputting the second voltage.

2. The circuit according to claim 1, characterized in that The input end of the control unit includes a first input end and a second input end, and the signal source includes a first signal source and a second signal source; The first input terminal of the control unit is connected to the first signal source, and the second input terminal of the control unit is connected to the second signal source.

3. The circuit according to claim 1, characterized in that The switch unit includes a fourth resistor, a sixth resistor, a seventh resistor, a sixteenth resistor, a first switch tube, a second switch tube, a first capacitor and a fourth capacitor; Wherein, the first end of the fourth resistor is connected to the input power supply, the first end of the sixth resistor and the source of the first switch tube, the second end of the fourth resistor is connected to the gate of the second switch tube, the first end of the sixteenth resistor, the output end of the protection unit and the output end of the control unit, the gate of the first switch tube is connected to the second end of the sixth resistor, the first end of the seventh resistor, the drain of the second switch tube and the first end of the first capacitor, and the drain of the first switch tube is connected to the second end of the first capacitor and the first end of the fourth capacitor as the output end of the switch unit; The source of the second switch tube, the second end of the sixteenth resistor and the second end of the fourth capacitor are grounded.

4. The circuit according to claim 1, characterized in that The protection unit includes a first voltage stabilizing diode, an eighth resistor, a thirteenth resistor, a fifteenth resistor, a fourth switch tube and an eighth capacitor; The cathode of the first voltage zener diode is connected to the input power supply and the first end of the eighth capacitor, the anode of the first voltage zener diode is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the first end of the thirteenth resistor and the first end of the fifteenth resistor, the second end of the thirteenth resistor is connected to the base of the fourth switch tube, and the collector of the fourth switch tube is connected to the controlled end of the switch unit; The second end of the eighth capacitor, the second end of the fifteenth resistor and the emitter of the fourth switch tube are grounded.

5. The circuit according to claim 2, characterized in that The control unit includes a ninth resistor, a twelfth resistor, a second diode and a fourth diode; Wherein, a first end of the ninth resistor is connected to the first signal source, a second end of the ninth resistor is connected to the anode of the second diode, and a cathode of the second diode is connected to the cathode of the fourth diode and the controlled end of the switch unit; A first end of the twelfth resistor is connected to the second signal source, and a second end of the twelfth resistor is connected to the anode of the fourth diode.

6. The circuit according to claim 2, characterized in that The first signal source is an analog signal source, and the second signal source is a digital signal source.

7. The circuit according to claim 4, characterized in that The protection voltage threshold is a voltage stabilization value of the first voltage stabilizing diode.

8. The circuit according to claim 4, characterized in that The voltage stabilization value of the first voltage stabilizing diode is 30V.

9. The circuit according to any one of claims 1 to 8, characterized in that: The control signal is at a high level, and the protection signal is at a low level.

10. An overvoltage protection device, characterized in that: include: An overvoltage protection circuit as claimed in any one of claims 1 to 9.

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