Direct-current voltage conversion circuit

Abstract

The utility model discloses a DC voltage conversion circuit, which comprises an input port, an output port, an overvoltage protection module and a voltage conversion module, the input port is connected with the input end of the overvoltage protection module, the output end of the overvoltage protection module is connected with the input end of the voltage conversion module, and the output end of the voltage conversion module is connected with the output end of the overvoltage protection module. And the output end of the voltage conversion module is connected with the output port. According to the technical scheme, the overvoltage protection module is arranged between the input port and the voltage conversion module, when the direct current voltage amplitude of the input port is small, the triode Q2 is switched on, the input port transmits voltage to the voltage conversion module, when the direct current voltage amplitude of the input port is too high and overvoltage abnormal conditions occur, the triode Q2 is switched off, and the overvoltage protection module is switched off. The input port is prevented from transmitting voltage to the voltage conversion module, so that an overvoltage protection function is realized, and the safety and reliability of the direct-current voltage conversion circuit in the application process are improved.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and more specifically to a DC voltage conversion circuit with overvoltage protection function. Background Technology

[0002] In the field of electronic circuits, DC voltage conversion circuits are used in various electrical appliances in daily life to convert the voltage within a certain range of input to another range of output.

[0003] In existing technologies, conversion circuits are generally based on integrated conversion chips, which greatly simplifies the circuit structure. However, the drawback is that the safety and reliability of the conversion circuit are not good. Its safety and reliability mainly rely on the conversion chip, and the conversion chip rarely has overvoltage protection, which means that the conversion circuit cannot protect against excessively high input voltages. Utility Model Content

[0004] To solve the above-mentioned technical problems, the purpose of this utility model is to provide a DC voltage conversion circuit with overvoltage protection function.

[0005] The technical solution adopted by this utility model to solve the problem is:

[0006] A DC voltage conversion circuit includes an input port, an output port, an overvoltage protection module, and a voltage conversion module. The input port is connected to the input terminal of the overvoltage protection module, the output terminal of the overvoltage protection module is connected to the input terminal of the voltage conversion module, and the output terminal of the voltage conversion module is connected to the output port.

[0007] The overvoltage protection module includes resistors R1, R2, R3, and R4, PNP transistors Q1 and Q2, and a Zener diode D1. The input port is connected to the negative terminal of the Zener diode D1 via resistors R1 and R2. The positive terminal of the Zener diode D1 is connected to ground. The base of transistor Q1 is connected to the junction of resistors R1 and R2. The emitter of transistor Q1 is connected to the input port. The collector of transistor Q1 is connected to ground via resistor R4. The two ends of resistor R3 are connected to the collector and emitter of transistor Q1 respectively. The emitter of transistor Q2 is connected to the emitter of transistor Q1. The base of transistor Q2 is connected to the junction of resistors R3 and R4. The collector of transistor Q2 is connected to the input terminal of the voltage conversion module.

[0008] As a further improvement to the above technical solution, the overvoltage protection module also includes capacitor C1 and capacitor C2. One end of capacitor C1 is connected to the input port, and the other end of capacitor C1 is connected to ground. One end of capacitor C2 is connected to the collector of transistor Q2, and the other end of capacitor C2 is connected to ground.

[0009] As a further improvement to the above technical solution, the overvoltage protection module also includes diode D2 and diode D3. The positive terminal of diode D2 is connected to the input port, the negative terminal of diode D2 is connected to the emitter of transistor Q1, the positive terminal of diode D3 is connected to the collector of transistor Q2, and the negative terminal of diode D3 is connected to the emitter of transistor Q2.

[0010] As a further improvement to the above technical solution, the voltage conversion module includes a converter chip of model LA1912, resistors R5, R6, R7, and R8, capacitors C3, C4, and C5, inductor L1, Zener diode D4, and diode D5.

[0011] The output terminal of the overvoltage protection module is connected to the D terminal of the converter chip. The output terminal of the overvoltage protection module is connected to the VCC terminal of the converter chip through the resistor R5. One end of the capacitor C3 is connected to the VCC terminal of the converter chip, and the other end of the capacitor C3 is connected to ground. The negative terminal of the Zener diode D4 is connected to the VCC terminal of the converter chip, and the positive terminal of the Zener diode D4 is connected to ground. The CS terminal of the converter chip is connected to the negative terminal of the diode D5 and one end of the inductor L1 through the resistor R8. The positive terminal of the diode D5 is connected to ground. The other end of the inductor L1 is connected to one end of the capacitor C5, one end of the resistor R6, and the output port. The other end of the capacitor C5 is connected to ground. The other end of the resistor R6 is connected to ground through the resistor R7. The FB1 terminal of the converter chip is connected to the junction of the resistors R6 and R7. The FB1 terminal of the converter chip is connected to ground through the capacitor C4.

[0012] The beneficial effects of this utility model are as follows: This technical solution sets up an overvoltage protection module between the input port and the voltage conversion module. When the DC voltage amplitude at the input port is small, transistor Q2 is turned on, and the input port transmits voltage to the voltage conversion module. When the DC voltage amplitude at the input port is too high and an overvoltage abnormality occurs, transistor Q2 is turned off, preventing the input port from transmitting voltage to the voltage conversion module. This achieves the overvoltage protection function and improves the safety and reliability of the DC voltage conversion circuit during application. Attached Figure Description

[0013] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0014] Figure 1 This is a circuit module framework diagram of this utility model;

[0015] Figure 2 This is the circuit diagram of the overvoltage protection module in this utility model;

[0016] Figure 3 This is the circuit diagram of the voltage conversion module in this utility model. Detailed Implementation

[0017] This section will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but they should not be construed as limiting the scope of protection of the present utility model.

[0018] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional 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 limitations on this utility model.

[0019] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0020] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0021] Reference Figures 1 to 3 This application discloses a DC voltage conversion circuit. In its first embodiment, it includes an input port, an output port, an overvoltage protection module, and a voltage conversion module. The input port is connected to the input terminal of the overvoltage protection module, the output terminal of the overvoltage protection module is connected to the input terminal of the voltage conversion module, and the output terminal of the voltage conversion module is connected to the output port.

[0022] The overvoltage protection module includes resistors R1, R2, R3, and R4, PNP transistors Q1 and Q2, and a Zener diode D1. The input port is connected to the negative terminal of the Zener diode D1 via resistors R1 and R2. The positive terminal of the Zener diode D1 is connected to ground. The base of transistor Q1 is connected to the junction of resistors R1 and R2. The emitter of transistor Q1 is connected to the input port. The collector of transistor Q1 is connected to ground via resistor R4. The two ends of resistor R3 are connected to the collector and emitter of transistor Q1 respectively. The emitter of transistor Q2 is connected to the emitter of transistor Q1. The base of transistor Q2 is connected to the junction of resistors R3 and R4. The collector of transistor Q2 is connected to the input terminal of the voltage conversion module.

[0023] Specifically, in this embodiment, an overvoltage protection module is provided between the input port and the voltage conversion module. When the DC voltage amplitude at the input port is small, the transistor Q2 is turned on, and the input port transmits voltage to the voltage conversion module. When the DC voltage amplitude at the input port is too high and an overvoltage abnormality occurs, the transistor Q2 is turned off to prevent the input port from transmitting voltage to the voltage conversion module, thereby realizing the overvoltage protection function and improving the safety and reliability of the DC voltage conversion circuit in application.

[0024] As a further preferred embodiment, in this example, the overvoltage protection module further includes capacitors C1 and C2. One end of capacitor C1 is connected to the input port, and the other end of capacitor C1 is connected to ground. One end of capacitor C2 is connected to the collector of transistor Q2, and the other end of capacitor C2 is connected to ground. This embodiment uses capacitors C1 and C2 to filter the DC voltage at both the input and output terminals of the overvoltage protection module.

[0025] As a further preferred embodiment, in this embodiment, the overvoltage protection module further includes diode D2 and diode D3. The positive terminal of diode D2 is connected to the input port, the negative terminal of diode D2 is connected to the emitter of transistor Q1, the positive terminal of diode D3 is connected to the collector of transistor Q2, and the negative terminal of diode D3 is connected to the emitter of transistor Q2.

[0026] As a further preferred embodiment, in this embodiment, the voltage conversion module includes a converter chip of model LA1912, resistors R5, R6, R7, R8, R9, and R10, capacitors C3, C4, C5, and C6, inductor L1, Zener diode D4, diode D5, and diode D6.

[0027] The output terminal of the overvoltage protection module is connected to the D terminal of the converter chip. The output terminal of the overvoltage protection module is also connected to the VCC terminal of the converter chip via resistor R5. One end of capacitor C3 is connected to the VCC terminal of the converter chip, and the other end of capacitor C3 is connected to ground. The negative terminal of Zener diode D4 is connected to the VCC terminal of the converter chip, and the positive terminal of Zener diode D4 is connected to ground. The CS terminal of the converter chip is connected to the negative terminal of diode D5 and one end of inductor L1 via resistor R8. The positive terminal of diode D5 is connected to ground. The other end of inductor L1 is connected to the negative terminal of diode D5 and one end of inductor L1. One end of capacitor C5, one end of resistor R6, and the output port are connected. The other end of capacitor C5 is connected to ground. The other end of resistor R6 is connected to ground through resistor R7. The FB1 terminal of the converter chip is connected to the junction of resistor R6 and resistor R7. The FB1 terminal of the converter chip is connected to ground through capacitor C4. The output port is connected to the anode of diode D6. The cathode of diode D6 is connected to the VCC terminal of the converter chip through resistor R9. The FB2 terminal of the converter chip is connected to ground through resistor R10. Capacitor C6 and resistor R10 are connected in parallel.

[0028] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the concept of this utility model and the contents of the specification and drawings of this utility model, or direct or indirect applications in other related technical fields, are included within the patent protection scope of this utility model.

Claims

1. A direct current voltage conversion circuit, characterized by: It includes an input port, an output port, an overvoltage protection module, and a voltage conversion module. The input port is connected to the input terminal of the overvoltage protection module, the output terminal of the overvoltage protection module is connected to the input terminal of the voltage conversion module, and the output terminal of the voltage conversion module is connected to the output port. The overvoltage protection module includes resistors R1, R2, R3, and R4, transistors Q1 and Q2, and a Zener diode D1. The input port is connected to the negative terminal of the Zener diode D1 via resistors R1 and R2. The positive terminal of the Zener diode D1 is connected to ground. The base of transistor Q1 is connected to the junction of resistors R1 and R2. The emitter of transistor Q1 is connected to the input port. The collector of transistor Q1 is connected to ground via resistor R4. The two ends of resistor R3 are connected to the collector and emitter of transistor Q1 respectively. The emitter of transistor Q2 is connected to the emitter of transistor Q1. The base of transistor Q2 is connected to the junction of resistors R3 and R4. The collector of transistor Q2 is connected to the input terminal of the voltage conversion module.

2. A DC voltage conversion circuit according to claim 1, characterized in that: The overvoltage protection module also includes capacitors C1 and C2. One end of capacitor C1 is connected to the input port, and the other end of capacitor C1 is connected to ground. One end of capacitor C2 is connected to the collector of transistor Q2, and the other end of capacitor C2 is connected to ground.

3. A DC voltage conversion circuit according to claim 2, characterised in that: The overvoltage protection module also includes diodes D2 and D3. The anode of diode D2 is connected to the input port, and the cathode of diode D2 is connected to the emitter of transistor Q1. The anode of diode D3 is connected to the collector of transistor Q2, and the cathode of diode D3 is connected to the emitter of transistor Q2.

4. A dc-dc voltage conversion circuit according to claim 1, characterized in that: The voltage conversion module includes a converter chip of model LA1912, resistors R5, R6, R7, and R8, capacitors C3, C4, and C5, inductor L1, Zener diode D4, and diode D5. The output terminal of the overvoltage protection module is connected to the D terminal of the converter chip. The output terminal of the overvoltage protection module is connected to the VCC terminal of the converter chip through the resistor R5. One end of the capacitor C3 is connected to the VCC terminal of the converter chip, and the other end of the capacitor C3 is connected to ground. The negative terminal of the Zener diode D4 is connected to the VCC terminal of the converter chip, and the positive terminal of the Zener diode D4 is connected to ground. The CS terminal of the converter chip is connected to the negative terminal of the diode D5 and one end of the inductor L1 through the resistor R8. The positive terminal of the diode D5 is connected to ground. The other end of the inductor L1 is connected to one end of the capacitor C5, one end of the resistor R6, and the output port. The other end of the capacitor C5 is connected to ground. The other end of the resistor R6 is connected to ground through the resistor R7. The FB1 terminal of the converter chip is connected to the junction of the resistors R6 and R7. The FB1 terminal of the converter chip is connected to ground through the capacitor C4.

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