DC power supply input overvoltage protection circuit and electronic equipment

Abstract

The utility model relates to the technical field of overvoltage protection circuits, in particular to a DC power supply input overvoltage protection circuit and electronic equipment. The circuit comprises an overvoltage detection module, a first switch module and a second switch module, the input end of the overvoltage detection module is connected with the first output end of an external power input module, and the output end is connected with the input end of the first switch module. The output end of the first switch module is connected with the first input end of the second switch module; the second input end of the second switch module is connected with the joint of the overvoltage detection module and the power input module, and the output end of the second switch module is connected with an external load. The overvoltage protection circuit is used for providing overvoltage protection of DC input, so that the damage of overvoltage input to electronic equipment is avoided, and the beneficial effects of improving the reliability of the circuit and further improving the use experience of a user are achieved.

Description

Technical Field

[0001] This application relates to the technical field of overvoltage protection circuits, and more particularly to a DC power input overvoltage protection circuit and electronic device. Background Technology

[0002] With the continuous advancement of technology, electronic products such as laptops, tablets, and fanless industrial control computers are becoming increasingly popular. However, this process has also brought about some noteworthy problems: different devices require a wide variety of power adapters with varying designs; some users are still using severely outdated power adapters; and there are even instances of adapters with incompatible voltages being connected to devices. These problems collectively lead to frequent occurrences of excessively high input voltage, which can potentially damage electronic equipment and, in severe cases, cause large-scale product failures.

[0003] Therefore, how to develop an effective overvoltage protection circuit to avoid damage to electronic devices caused by overvoltage input, improve circuit reliability, and thus improve the user experience is a technical problem that urgently needs to be solved. Utility Model Content

[0004] To overcome the shortcomings of the prior art, this application provides a DC power input overvoltage protection circuit and electronic device, which provides overvoltage protection for DC input, thereby avoiding damage to electronic device caused by overvoltage input, and achieving the beneficial effect of improving circuit reliability and thus improving user experience.

[0005] The technical solution adopted by this application to solve its technical problem is:

[0006] In a first aspect, this application provides a DC power input overvoltage protection circuit, the circuit comprising: an overvoltage detection module, a first switch module, and a second switch module;

[0007] The input terminal of the overvoltage detection module is connected to the first output terminal of an external power input module, and the output terminal is connected to the input terminal of the first switch module. It is used to start and stop the overvoltage detection module according to the DC signal output by the power input module, and to send a first control signal to the first switch module based on the start and stop status of the overvoltage detection module.

[0008] The output terminal of the first switch module is connected to the first input terminal of the second switch module, and is used to start and stop the first switch module according to the first control signal, and send a second control signal to the second switch module based on the start and stop status of the first switch module;

[0009] The second input terminal of the second switch module is connected to the connection point between the overvoltage detection module and the power input module, and the output terminal of the second switch module is connected to an external load. It is used to start and stop the second switch module according to the second control signal, and to control the on / off state of the signal circuit from the power input module to the load based on the start / stop state of the second switch module.

[0010] Optionally, the overvoltage detection module includes a first resistor, a second resistor, a third resistor, and a three-terminal Zener diode;

[0011] One end of the first resistor is connected to the connection point between the power input module and the second switch module, and the other end is connected to one end of the second resistor and the reference terminal of the three-terminal Zener diode. The other end of the second resistor is grounded.

[0012] The negative terminal of the three-terminal Zener diode is connected to one end of the third resistor, the other end of the third resistor is connected to the connection point between the power input module and the second switch module, and the positive terminal of the three-terminal Zener diode is grounded.

[0013] Optionally, the first switching module includes a fourth resistor, a fifth resistor, and an NMOS transistor;

[0014] One end of the fourth resistor is connected to the connection point between the three-terminal Zener diode and the third resistor, and the other end is connected to one end of the fifth resistor and the gate of the NMOS transistor. The other end of the fifth resistor is grounded.

[0015] The drain of the NMOS transistor is connected to the first input terminal of the second switching module, and the source of the NMOS transistor is grounded.

[0016] Optionally, the first switching module further includes a first capacitor;

[0017] One end of the first capacitor is connected to the connection point between the fourth resistor and the NMOS transistor, and the other end is grounded.

[0018] Optionally, the second switching module includes a first PMOS transistor, a sixth resistor, a seventh resistor, and a second capacitor;

[0019] One end of the sixth resistor is connected to the drain of the NMOS transistor, and the other end is connected to the gate of the first PMOS transistor, one end of the seventh resistor, and one end of the second capacitor. The other end of the second capacitor and the other end of the seventh resistor are both connected to the source of the first PMOS transistor.

[0020] The drain of the first PMOS transistor is connected to the load.

[0021] Optionally, the second switching module further includes a second PMOS transistor;

[0022] The gate of the second PMOS transistor is connected to the junction of the sixth resistor and the seventh resistor, the source of the second PMOS transistor is connected to the junction of the seventh resistor and the first PMOS transistor, and the drain of the second PMOS transistor is connected to the load.

[0023] Optionally, the three-terminal Zener diode used is model TL431.

[0024] Secondly, this application provides an electronic device equipped with the aforementioned DC power input overvoltage protection circuit.

[0025] The beneficial effects of this application are as follows: The overvoltage detection module detects the potential at the first output terminal of the power input module. If the potential is lower than a preset threshold, the three-terminal Zener diode in the overvoltage detection module is turned off, thereby sending a first control signal to turn on the switch in the first switching module. If the switch in the first switching module is turned on, a corresponding second control signal is sent to turn on the switch in the second switching module, thereby connecting the signal loop from the power input module to the external load and enabling normal signal transmission. If the potential reaches the preset threshold, the three-terminal Zener diode in the overvoltage detection module is turned on, thereby turning off the switch in the first switching module. If the switch in the first switching module is turned off, a corresponding second control signal is sent to turn off the switch in the second switching module, thereby disconnecting the signal loop from the power input module to the load and achieving voltage protection. Based on this, the above solution can provide overvoltage protection for DC input, thereby avoiding damage to electronic equipment caused by overvoltage input, improving circuit reliability, and thus enhancing the user experience. Attached Figure Description

[0026] Figure 1 This is a module connection diagram of the DC power input overvoltage protection circuit provided in the embodiments of this application;

[0027] Figure 2 This is a circuit diagram of the DC power input overvoltage protection circuit provided in the embodiments of this application;

[0028] Figure 3 This is a schematic diagram of the working principle of the TL431 three-terminal Zener diode provided in the embodiments of this application. Detailed Implementation

[0029] The present application will be further described below with reference to the accompanying drawings and embodiments.

[0030] The following will clearly and completely describe the concept, specific structure, and resulting technical effects of this application in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, features, and effects of this application. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are all within the scope of protection of this application. Furthermore, all connections / linkages involved in the patent do not simply refer to direct contact between components, but rather to the ability to form a better connection structure by adding or reducing connecting accessories according to specific implementation conditions. The various technical features in this application can be combined interactively without contradicting each other.

[0031] Reference Figure 1 , Figure 1 This is a module connection diagram of the DC power input overvoltage protection circuit provided in the embodiments of this application. The circuit includes an overvoltage detection module, a first switch module, and a second switch module. The following is a description of the connection diagram. Figure 1 A preliminary introduction to each module will be provided, specifically:

[0032] The input terminal of the overvoltage detection module is connected to the first output terminal of an external power input module, and the output terminal is connected to the input terminal of the first switch module.

[0033] Regarding the overvoltage detection module: it is used to start and stop the overvoltage detection module according to the DC signal output by the power input module, and to send a first control signal to the first switching module based on the start / stop state of the overvoltage detection module. Specifically, the overvoltage detection module includes switching devices such as a three-terminal Zener diode. In this embodiment, the overvoltage detection module detects the potential at the first output terminal of the power input module. If the potential is lower than a preset threshold, it controls the three-terminal Zener diode in the overvoltage detection module to turn off, thereby sending a first control signal to turn on the switching transistor in the first switching module; if the potential reaches the preset threshold, the three-terminal Zener diode in the overvoltage detection module turns on, thereby sending a corresponding first control signal to turn off the switching transistor in the first switching module.

[0034] Furthermore, the output terminal of the first switch module is connected to the first input terminal of the second switch module.

[0035] Regarding the first switching module: it is used to start and stop the first switching module according to the first control signal, and to send a second control signal to the second switching module based on the start / stop state of the first switching module. The first switching module includes switching devices such as NMOS transistors and transistors, and changes its on / off state based on the potential change at the connection point of the overvoltage detection module to the first switching transistor. In this embodiment, if the switching transistor in the first switching module is turned on, a corresponding second control signal is sent to control the switching transistor in the second switching module to turn on; otherwise, the sent second control signal is used to control the switching transistor in the second switching module to turn off.

[0036] Furthermore, the second input terminal of the second switch module is connected to the connection point between the overvoltage detection module and the power input module, and the output terminal of the second switch module is connected to an external load.

[0037] Regarding the second switching module: it is used to start and stop the second switching module according to the second control signal, and to control the connection and disconnection of the signal circuit from the power input module to the load based on the start / stop state of the second switching module. Specifically, when the second control signal controls the switching transistor in the second switching module to conduct, a signal circuit from the power input module to the load is formed; otherwise, the signal circuit from the power input module to the load is disconnected. It can be understood that, based on the above description, when the signal output by the power input module exceeds a preset threshold, the second switching module will eventually be disconnected, preventing the signal from being transmitted to the external load, thereby achieving overvoltage protection.

[0038] Reference Figure 2 , Figure 2 This is a circuit diagram of the DC power input overvoltage protection circuit provided in the embodiments of this application. Figure 2 This is a further disclosure of the above content, disclosing specific circuit design embodiments in each module. The following is in conjunction with... Figure 2 Further explanation of this plan:

[0039] The overvoltage detection module includes a first resistor PR5, a second resistor PR9, a third resistor PR3, and a three-terminal Zener diode PD1.

[0040] One end of the first resistor PR5 is connected to the connection point between the power input module and the second switch module, and the other end is connected to one end of the second resistor PR9 and the reference terminal of the three-terminal Zener diode PD1. The other end of the second resistor PR9 is grounded.

[0041] The negative terminal of the three-terminal Zener diode PD1 is connected to one end of the third resistor PR3, and the other end of the third resistor PR3 is connected to the connection point between the power input module and the second switch module. The positive terminal of the three-terminal Zener diode PD1 is grounded.

[0042] Specifically, the OVP (Over Voltage Protection) threshold at potential point a can be set using the first resistor PR5 and the second resistor PR9, which is the preset threshold in this application. In this embodiment, the potential point between the first resistor PR5 and the second resistor PR9 is used as the reference potential point b. When the voltage at point a reaches the preset threshold, the voltage at point b... It equals 2.5V. Specifically, .in, The resistance value of the second resistor PR9. Let PR5 be the resistance value of the first resistor. Let be the voltage at point a.

[0043] More specifically, the three-terminal Zener diode PD1 used in the embodiments of this application is model TL431, refer to... Figure 3 , Figure 3 This is a schematic diagram illustrating the working principle of the TL431 three-terminal Zener diode PD1 provided in this application embodiment. It can be seen that the TL431 internally includes a reference terminal R, a positive terminal A, and a negative terminal K, and integrates a comparator amplifier and a transistor. The comparator amplifier's positive input is connected to the reference terminal R, its inverting input is connected to a 2.5V reference voltage, and its output is connected to the base of the NPN transistor. The collector is connected to the negative terminal K, and the emitter is connected to the positive terminal A. When the voltage at the reference terminal K is greater than or equal to 2.5V, the comparator amplifier outputs a high level, turning on the transistor. When the transistor is on, the three-terminal Zener diode PD1 conducts; conversely, when the voltage is low, the three-terminal Zener diode PD1 is off.

[0044] More specifically, by employing the first resistor PR5, the second resistor PR9, and the third resistor PR3, when the voltage at point a is lower than a preset threshold, the voltage at point b is less than 2.5V. In this case, the Zener diode PD1 is in the off state, and the first control signal sent is used to control the first switching module to turn on, which is a high-level signal. Conversely, when the voltage at point a reaches the preset threshold, the voltage at point b is equal to 2.5V. In this case, the Zener diode PD1 is turned on, and the first control signal sent is used to control the first switching module to turn off, which is a low-level signal. The first control signal is located at point e, the connection point between the Zener diode PD1 and the third resistor PR3. The first switching module samples the voltage at point e as the first control signal.

[0045] Furthermore, the first switching module includes a fourth resistor PR6, a fifth resistor PR7, and an NMOS transistor PQ3;

[0046] One end of the fourth resistor PR6 is connected to the connection point of the three-terminal Zener diode PD1 and the third resistor PR3, and the other end is connected to one end of the fifth resistor PR7 and the gate of the NMOS transistor PQ3. The other end of the fifth resistor PR7 is grounded.

[0047] The drain of the NMOS transistor PQ3 is connected to the first input terminal of the second switching module, and the source of the NMOS transistor PQ3 is grounded.

[0048] Specifically, when the voltage at point e is high, the voltage at point c is equal to the voltage at point a through the voltage divider of the fourth resistor PR6 and the fifth resistor PR7, and the voltage at point c is greater than the turn-on voltage of NMOS transistor PQ3, causing NMOS transistor PQ3 to turn on; when the voltage at point e is low, the opposite is true. Since the three-terminal Zener diode PD1 is in the on state under this condition, point e is equivalent to ground, and the input voltage is pulled down to below the preset threshold through the third resistor PR3, the voltage at point c is 0, and under this condition, NMOS transistor PQ3 is turned off.

[0049] More specifically, the first switching module further includes a first capacitor PC9;

[0050] One end of the first capacitor PC9 is connected to the connection point between the fourth resistor PR6 and the NMOS transistor PQ3, and the other end is grounded.

[0051] By adopting the above technical solution, interference signals can be eliminated from the signal transmitted from point c to the gate of NMOS transistor PQ3, thereby improving signal reliability.

[0052] Furthermore, the second switching module includes a first PMOS transistor PQ2, a sixth resistor PR4, a seventh resistor PR2, and a second capacitor PC3;

[0053] One end of the sixth resistor PR4 is connected to the drain of the NMOS transistor PQ3, and the other end is connected to the gate of the first PMOS transistor PQ2, one end of the seventh resistor PR2 and one end of the second capacitor PC3. The other end of the second capacitor PC3 and the other end of the seventh resistor PR2 are both connected to the source of the first PMOS transistor PQ2.

[0054] The drain of the first PMOS transistor PQ2 is connected to the load.

[0055] Specifically, a potential point d is formed between the sixth resistor PR4 and the seventh resistor PR2. When the NMOS transistor PQ3 in the first switching module is turned on, the voltage at point d is equal to the voltage division at point a. Since point a is the source of the first PMOS transistor PQ2 and point d is the gate of the first PMOS transistor PQ2, the conduction condition of the PMOS transistor is met under these conditions, causing the first PMOS transistor PQ2 to conduct. After the first PMOS transistor PQ2 is turned on, the power output module (i.e., Figure 2 The DC_IN1 shown is connected to point a, and the first PMOS transistor PQ2 outputs the value VOUT (load).

[0056] Conversely, when the NMOS transistor PQ3 in the first switching module is turned off, the voltage at point d is equal to the voltage at point a, and the first PMOS transistor PQ2 is turned off, thereby shutting off the signal circuit and preventing the signal from being output to VOUT, thus achieving the effect of overvoltage protection.

[0057] Furthermore, the second switching module also includes a second PMOS transistor PQ1;

[0058] The gate of the second PMOS transistor PQ1 is connected to the connection point of the sixth resistor PR4 and the seventh resistor PR2, the source of the second PMOS transistor PQ1 is connected to the connection point of the seventh resistor PR2 and the first PMOS transistor PQ2, and the drain of the second PMOS transistor PQ1 is connected to the load.

[0059] Specifically, similar to the first PMOS transistor PQ2 mentioned above, its conduction and working principle will not be described in detail here.

[0060] Secondly, this application provides an electronic device equipped with the aforementioned DC power input overvoltage protection circuit.

[0061] The above is a detailed description of the preferred embodiments of this application. However, the invention of this application is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A DC power input overvoltage protection circuit, characterized in that, The circuit includes: an overvoltage detection module, a first switch module, and a second switch module; The input terminal of the overvoltage detection module is connected to the first output terminal of an external power input module, and the output terminal is connected to the input terminal of the first switch module. It is used to start and stop the overvoltage detection module according to the DC signal output by the power input module, and to send a first control signal to the first switch module based on the start and stop status of the overvoltage detection module. The output terminal of the first switch module is connected to the first input terminal of the second switch module, and is used to start and stop the first switch module according to the first control signal, and send a second control signal to the second switch module based on the start and stop status of the first switch module; The second input terminal of the second switch module is connected to the connection point between the overvoltage detection module and the power input module, and the output terminal of the second switch module is connected to an external load. It is used to start and stop the second switch module according to the second control signal, and to control the on / off state of the signal circuit from the power input module to the load based on the start / stop state of the second switch module.

2. The DC power input overvoltage protection circuit according to claim 1, characterized in that, The overvoltage detection module includes a first resistor, a second resistor, a third resistor, and a three-terminal Zener diode; One end of the first resistor is connected to the connection point between the power input module and the second switch module, and the other end is connected to one end of the second resistor and the reference terminal of the three-terminal Zener diode. The other end of the second resistor is grounded. The negative terminal of the three-terminal Zener diode is connected to one end of the third resistor, the other end of the third resistor is connected to the connection point between the power input module and the second switch module, and the positive terminal of the three-terminal Zener diode is grounded.

3. The DC power input overvoltage protection circuit according to claim 2, characterized in that, The first switching module includes a fourth resistor, a fifth resistor, and an NMOS transistor; One end of the fourth resistor is connected to the connection point between the three-terminal Zener diode and the third resistor, and the other end is connected to one end of the fifth resistor and the gate of the NMOS transistor. The other end of the fifth resistor is grounded. The drain of the NMOS transistor is connected to the first input terminal of the second switching module, and the source of the NMOS transistor is grounded.

4. The DC power input overvoltage protection circuit according to claim 3, characterized in that, The first switching module also includes a first capacitor; One end of the first capacitor is connected to the connection point between the fourth resistor and the NMOS transistor, and the other end is grounded.

5. The DC power input overvoltage protection circuit according to claim 3, characterized in that, The second switching module includes a first PMOS transistor, a sixth resistor, a seventh resistor, and a second capacitor; One end of the sixth resistor is connected to the drain of the NMOS transistor, and the other end is connected to the gate of the first PMOS transistor, one end of the seventh resistor, and one end of the second capacitor. The other end of the second capacitor and the other end of the seventh resistor are both connected to the source of the first PMOS transistor. The drain of the first PMOS transistor is connected to the load.

6. The DC power input overvoltage protection circuit according to claim 5, characterized in that, The second switching module also includes a second PMOS transistor; The gate of the second PMOS transistor is connected to the junction of the sixth resistor and the seventh resistor, the source of the second PMOS transistor is connected to the junction of the seventh resistor and the first PMOS transistor, and the drain of the second PMOS transistor is connected to the load.

7. The DC power input overvoltage protection circuit according to claim 2, characterized in that, The three-terminal Zener diode used is model TL431.

8. An electronic device, characterized in that, It is equipped with a DC power input overvoltage protection circuit as described in any one of claims 1-7.

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