Novel overvoltage protection circuit
By combining resistor voltage divider and Zener diode clamping circuit with PNP transistor and PMOS circuit, the problems of traditional overvoltage protection circuits being unable to flexibly adjust the threshold and having a slow response speed are solved. This achieves flexible protection threshold setting and fast response, simplifies the circuit structure, reduces costs, and improves system stability.
Patent Information
- Application Number
- CN202422897473.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2034-11-27
AI Technical Summary
Traditional overvoltage protection circuits have fixed protection thresholds that cannot be flexibly adjusted, have slow response speeds and high circuit complexity, making it difficult to meet the diverse needs of modern electronic devices.
A resistor voltage divider circuit and a Zener diode clamping circuit are combined with a PNP transistor and a PMOS circuit. The protection threshold is set by adjusting the resistor value, and the switching characteristics of the transistor and PMOS transistor are used to achieve fast response.
It enables flexible protection threshold settings and fast response, simplifies circuit structure, reduces costs, and improves system stability and reliability.
Smart Images
Figure CN223514596U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electronic circuit protection technology, and in particular to a novel overvoltage protection circuit. Background Technology
[0002] In modern electronic devices, overvoltage protection circuits are a crucial component for ensuring safe system operation. Traditional overvoltage protection circuits typically use the rated operating voltage of a Zener diode to set the protection threshold. However, this design has limitations because the rated operating voltage of the Zener diode is fixed during manufacturing and cannot be adjusted according to actual needs. This makes it difficult for traditional overvoltage protection circuits to meet the requirements of different protection thresholds in certain application scenarios.
[0003] Furthermore, traditional overvoltage protection circuits also have shortcomings in terms of response speed and circuit complexity. For example, some circuits respond slowly when overvoltage is detected, failing to protect subsequent circuits in time; others are too complex, increasing cost and failure rate.
[0004] Therefore, there is a need for an overvoltage protection circuit that can flexibly set the protection threshold, has a fast response speed, and a simple structure to meet the needs of modern electronic devices. Utility Model Content
[0005] This invention proposes a novel overvoltage protection circuit that allows for flexible setting of protection thresholds, fast response speed, and simple structure, thus solving the aforementioned problems existing in the use of existing technologies.
[0006] The technical solution of this utility model is implemented as follows: A novel overvoltage protection circuit includes an input detection circuit and an output control circuit. The input detection circuit includes a resistor voltage divider circuit and a Zener diode clamping circuit. The output control circuit includes a PNP transistor circuit and a PMOS circuit. The resistor voltage divider circuit includes resistors R1 and R2. The first end of resistor R1 is connected to an external DC power supply, and the second end of resistor R1 is connected to the first end of resistor R2. The Zener diode clamping circuit includes a Zener diode DZ2. The second end of resistor R2 is connected to the second end of Zener diode DZ2, and the first end of Zener diode DZ2 is grounded. The PNP transistor circuit includes a transistor Q2, and the PMOS circuit includes a PMOS transistor Q1. The base B of transistor Q2 is connected to the second end of resistor R1 and the first end of resistor R2. The emitter E of transistor Q2 is connected to an external DC power supply, and the collector C of transistor Q2 is connected to the gate G of PMOS transistor Q1.
[0007] Preferably, the present invention further includes a Zener diode DZ2, the second end of which is connected to an external DC power supply, and the first end of the Zener diode DZ1 is connected to the gate G of the PMOS transistor Q1.
[0008] Preferably, the present invention further includes resistors R3 and R4, wherein the first end of resistor R4 is connected to an external DC power supply, the second end of resistor R4 is connected to the gate G of PMOS transistor Q1, the first end of resistor R3 is connected to the gate G of PMOS transistor Q1, and the second end of resistor R3 is grounded.
[0009] In summary, the beneficial effects of this utility model are as follows:
[0010] 1. This invention features flexible protection threshold settings. By adjusting the resistance values of resistors R1 and R2, different overvoltage protection thresholds can be easily set to meet the needs of various application scenarios. Furthermore, this invention boasts a fast response speed. The coordinated design of the input detection circuit and output control circuit enables the circuit to respond quickly upon detecting overvoltage, promptly disconnecting the load from the power supply and protecting subsequent circuits from damage. The entire circuit is remarkably simple, using only a small number of electronic components, which not only reduces costs but also simplifies the design and manufacturing process, improving system stability and reliability. Attached Figure Description
[0011] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0012] Figure 1 This is a schematic diagram of the overall structure of this utility model. Detailed Implementation
[0013] The following will refer to the appendix in the embodiments of this utility model. Figure 1 The technical solutions in the embodiments of this utility model are clearly and completely described herein. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0014] Example:
[0015] like Figure 1As shown, this utility model discloses a novel overvoltage protection circuit, including an input detection circuit and an output control circuit. The input detection circuit includes a resistor voltage divider circuit and a Zener diode clamping circuit. The input detection circuit is used to provide a control signal to the output control circuit, while the output control circuit includes a PNP transistor circuit and a PMOS circuit. The output control circuit is responsible for turning the output on or off.
[0016] Specifically, the resistor divider circuit includes resistors R1 and R2. The first end of resistor R1 is connected to an external DC power supply, and the second end of resistor R1 is connected to the first end of resistor R2. The Zener diode clamping circuit includes a Zener diode DZ2. The second end of resistor R2 is connected to the cathode of the second end of Zener diode DZ2, and the anode of the first end of Zener diode DZ2 is grounded.
[0017] Furthermore, the PNP transistor circuit includes transistor Q2, and the PMOS circuit includes PMOS transistor Q1. The base (B) of transistor Q2 is connected to the second terminal of resistor R1 and the first terminal of resistor R2. The emitter (E) of transistor Q2 is connected to an external DC power supply, and the collector (C) of transistor Q2 is connected to the gate (G) of PMOS transistor Q1. Transistor Q2 controls the conduction and cutoff of PMOS transistor Q1. The source (S) of PMOS transistor Q1 is connected to the external DC power supply at the input terminal, and the drain (D) is connected to the load at the output terminal. PMOS transistor Q1 acts as the main switch, controlling the on / off state of the output voltage.
[0018] In addition, this utility model also includes a Zener diode DZ2, a resistor R3 and a resistor R4. The cathode of the second end of the Zener diode DZ2 is connected to an external DC power supply. The anode of the first end of the Zener diode DZ1 is connected to the gate G of the PMOS transistor Q1. The first end of the resistor R4 is connected to an external DC power supply. The second end of the resistor R4 is connected to the gate G of the PMOS transistor Q1. The first end of the resistor R3 is connected to the gate G of the PMOS transistor Q1. The second end of the resistor R3 is grounded.
[0019] The following is the working principle of this overvoltage protection circuit:
[0020] I. Circuit Composition
[0021] 1. Input detection circuit: includes resistors R1 and R2 and Zener diode DZ2.
[0022] 2. Output control circuit: includes transistor Q2, PMOS transistor Q1, resistor R3, resistor R4 and Zener diode DZ1.
[0023] II. Working Principle
[0024] 1. Normal working status
[0025] (1) Input voltage: Assume the external DC power supply voltage is V in .
[0026] (2) Resistor voltage divider: Resistors R1 and R2 form a voltage divider network to divide the input voltage V in After voltage division, an intermediate voltage V is obtained. mid .
[0027] V mid =V in ×R2 / (R1+R2)
[0028] (3) Zener diode DZ2: The reverse breakdown voltage of Zener diode DZ2 is V Z2 When V mid <V Z2 At this time, the Zener diode DZ2 is not conducting, the base potential of transistor Q2 is high, and transistor Q2 is conducting.
[0029] (4) Transistor Q2: When transistor Q2 is turned on, its collector potential is low and the gate potential of PMOS transistor Q1 is also low.
[0030] (5) PMOS transistor Q1: The gate-source voltage V of PMOS transistor Q1 GS When the value is negative, PMOS transistor Q1 is turned on, and the output voltage V... out Equal to input voltage V in .
[0031] 2. Overvoltage protection status
[0032] (1) Input voltage increases: When the input voltage V in When it rises to a certain level, V is obtained. mid >V Z2 At that time, the Zener diode DZ2 is turned on.
[0033] (2) Zener diode DZ2 is turned on: After Zener diode DZ2 is turned on, the base potential of transistor Q2 is clamped at V. Z2 The base potential decreases.
[0034] (3) Transistor Q2 is cut off: The base potential decreases, causing transistor Q2 to be cut off, and its collector potential increases.
[0035] (4) PMOS transistor Q1 is turned off: After transistor Q2 is turned off, the gate potential of PMOS transistor Q1 increases, and the gate-source voltage V GS When the voltage approaches 0V, PMOS transistor Q1 is cut off, and the output voltage V... out The circuit was cut off, protecting subsequent circuits from excessive voltage.
[0036] 3. Function of the component
[0037] (1) Resistors R1 and R2: used for voltage division. Different overvoltage protection thresholds can be set by adjusting their resistance ratio.
[0038] (2) Zener diode DZ2: used to detect whether the input voltage exceeds the set protection threshold.
[0039] (3) Transistor Q2: As a switch, it controls the conduction and cutoff of PMOS transistor Q1.
[0040] (4) PMOS transistor Q1: as the main switch, it controls the on and off of the output voltage.
[0041] (5) Resistors R3 and R4: provide pull-down and pull-up resistors for the gate of PMOS transistor Q1, respectively, to ensure that the PMOS transistor is in a safe state when there is no control signal.
[0042] (6) Zener diode DZ1: Used to protect the gate of PMOS transistor Q1 and prevent excessive gate-source voltage from damaging the PMOS transistor.
[0043] III. Summary
[0044] The above analysis shows that this overvoltage protection circuit achieves flexible overvoltage protection threshold setting through a simple resistor voltage divider and Zener diode clamping circuit. Simultaneously, it utilizes the switching characteristics of PNP and PMOS transistors to achieve rapid overvoltage response, effectively protecting subsequent circuits from damage caused by excessive voltage. This design is not only simple in structure but also reliable in performance, making it suitable for various applications requiring overvoltage protection.
[0045] It should also be noted that the terms used in this utility model, such as "front", "rear", "vertical", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this utility model.
[0046] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A novel overvoltage protection circuit, characterized in that: The circuit includes an input detection circuit and an output control circuit. The input detection circuit includes a resistor voltage divider circuit and a Zener diode clamping circuit. The output control circuit includes a PNP transistor circuit and a PMOS circuit. The resistor voltage divider circuit includes resistors R1 and R2. The first end of resistor R1 is connected to an external DC power supply, and the second end of resistor R1 is connected to the first end of resistor R2. The Zener diode clamping circuit includes a Zener diode DZ2. The second end of resistor R2 is connected to the second end of Zener diode DZ2, and the first end of Zener diode DZ2 is grounded. The PNP transistor circuit includes a transistor Q2, and the PMOS circuit includes a PMOS transistor Q1. The base B of transistor Q2 is connected to the second end of resistor R1 and the first end of resistor R2. The emitter E of transistor Q2 is connected to an external DC power supply, and the collector C of transistor Q2 is connected to the gate G of PMOS transistor Q1.
2. The novel overvoltage protection circuit according to claim 1, characterized in that: It also includes a Zener diode DZ2, the second end of which is connected to an external DC power supply, and the first end of the Zener diode DZ1 is connected to the gate G of the PMOS transistor Q1.
3. A novel overvoltage protection circuit according to claim 2, characterized in that: It also includes resistors R3 and R4. The first end of resistor R4 is connected to an external DC power supply, and the second end of resistor R4 is connected to the gate G of PMOS transistor Q1. The first end of resistor R3 is connected to the gate G of PMOS transistor Q1, and the second end of resistor R3 is grounded.