Short-circuit protection circuit for power output

Abstract

The invention discloses a short-circuit protection circuit for power supply output, and relates to the technical field of power supply protection. Comprising a direct-current power supply conversion module, a control circuit, a voltage division circuit and a switching circuit. The control circuit adopts voltage output feedback to control on-off of a triode, the voltage division circuit adopts a resistor to divide voltage, and the switching circuit comprises a key switch K connected with a capacitor C2 in parallel. The triode is used as a switch control unit, so that a switch can be controlled in time, and the protection effect is efficiently and reliably achieved; after the short-circuit protection is cancelled, the key switch K is pressed down, the protection circuit can be operated again, the power output is protected continuously, and reinstallation is not needed.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply protection, and in particular to a short-circuit protection circuit for power supply output. Background Art

[0002] Power output, the user accidentally miswires or accidentally short-circuits, causing the entire circuit to burn out, and the repair process is cumbersome and costly. In addition, when short-circuited, the entire circuit system is unsafe, which is a very high potential danger. It is extremely important to short-circuit protection for power output.

[0003] In the prior art, when a short circuit occurs due to excessive current in the circuit, the fuse will blow directly, cutting off the entire circuit to protect the entire circuit.

[0004] The defects of the above-mentioned prior art are that the fuse blowing protection is irreversible and belongs to one-time protection. Once the fuse blows, it can only be reinstalled. Summary of the invention

[0005] Based on this, it is necessary to provide a short-circuit protection circuit for power supply output in response to the above technical problems.

[0006] The embodiment of the present invention provides a short-circuit protection circuit for power supply output, comprising: an input voltage VIN connected to the source S of a field effect transistor Q9, the gate G of the field effect transistor Q9 connected to the collector c of a transistor Q11, the base b of the transistor Q11 connected to one end of the resistor R18; another input voltage VIN connected to one end of a capacitor C2, the other end of the capacitor C2 respectively connected to the other end of the resistor R18 and one end of a resistor R19; the other end of the resistor R19 connected to the base b of the transistor Q12, the collector c of the transistor Q12 connected to the gate G of the field effect transistor Q10, the drain D of the field effect transistor Q10 connected to a voltage output terminal VOUT; the voltage output terminal VOUT connected to one end of a resistor 17, the other end of the resistor R17 connected to a resistor R20, the other end of the resistor R20 is grounded;

[0007] The switch circuit comprises: a key switch K connected in parallel with the capacitor C2;

[0008] When a short circuit occurs, the voltage at the voltage output terminal VOUT is 0V, the capacitor C2 is equivalent to being disconnected, the input voltage VIN cannot supply power to the resistor R18 and the resistor R19, the transistor Q11 and the transistor Q12 are cut off, the field effect transistor Q9 and the field effect transistor Q10 are turned off, the input voltage VIN is cut off, and the entire circuit is protected; after the short circuit is canceled, the key switch K is pressed and the protection circuit is restarted.

[0009] In addition, it also includes a voltage divider circuit: one end of the resistor R15 is connected to the collector C pole of the transistor Q11, and the other end of the resistor R15 is connected to the source S pole of the field effect transistor Q9; one end of the resistor 16 is connected to the collector C pole of the transistor Q12, and the other end of the resistor R16 is connected to the source S pole of the field effect transistor Q10.

[0010] In addition, a control circuit is also included: the switching of the transistor Q11 and the transistor Q12 is controlled by feedback from the voltage output terminal VOUT.

[0011] In addition, the emitter and e-pole of the transistor Q11 are grounded, and the emitter and e-pole of the transistor Q12 are grounded.

[0012] In addition, the drain D of the field effect transistor Q9 is connected to one end of the DC power conversion module, and the source S of the field effect transistor Q10 is connected to the other end of the DC power conversion module, so as to control the input voltage VIN to supply power to the subsequent circuit.

[0013] Compared with the prior art, the short-circuit protection circuit for power output provided by the embodiment of the present invention has the following beneficial effects:

[0014] The transistor used in the present invention is used as a switch control unit, which can control the switch in time and achieve the protection effect efficiently and reliably; after the short-circuit protection is revoked, the protection circuit can be re-run by pressing the key switch K to continue to protect the power output without reinstallation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention is a principle block diagram of a short-circuit protection circuit for a power supply output provided in an embodiment. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0017] In one embodiment, a short-circuit protection circuit for a power supply output is provided, such as Figure 1 As shown, including:

[0018] One input voltage VIN is connected to the source S of the field effect transistor Q9, the gate G of the field effect transistor Q9 is connected to the collector c of the transistor Q11, and the base b of the transistor Q11 is connected to the resistor R18; another input voltage VIN is connected to one end of the capacitor C2, and the other end of the capacitor C2 is respectively connected to the other end of the resistor R18 and one end of the resistor R19; the other end of the resistor R19 is connected to the base b of the transistor Q12, the collector c of the transistor Q12 is connected to the gate G of the field effect transistor Q10, and the drain D of the field effect transistor Q10 is connected to the voltage output terminal VOUT; the voltage output terminal VOUT is connected to one end of the resistor 17, the other end of the resistor R17 is connected to the resistor R20, and the other end of the resistor R20 is grounded.

[0019] The switch circuit includes: a key switch K connected in parallel with the capacitor C2.

[0020] The voltage divider circuit includes: one end of the resistor R15 is connected to the collector C pole of the transistor Q11, and the other end of the resistor R15 is connected to the source S pole of the field effect transistor Q9; one end of the resistor R16 is connected to the collector C pole of the transistor Q12, and the other end of the resistor R16 is connected to the source S pole of the field effect transistor Q10.

[0021] The control circuit includes: using voltage output feedback to control the switch of the transistor, and controlling the transistor Q11 and the transistor Q12 through the voltage output terminal VOUT feedback. The emitter e-pole of the transistor Q11 is grounded, and the emitter e-pole of the transistor Q12 is grounded.

[0022] The drain D of the field effect transistor Q9 is connected to one end of the DC power conversion module, and the source S of the field effect transistor Q10 is connected to the other end of the DC power conversion module, so as to control the input voltage VIN to supply power to the subsequent circuit.

[0023] The circuit starts the normal operation of the whole circuit through the starting circuit; the control circuit uses voltage output feedback to control the switch of the transistor, thereby achieving the function of controlling the switch; the voltage divider circuit uses resistor voltage divider.

[0024] The input voltage VIN of the control field effect tube is divided into two paths. One path passes through capacitor C2, resistor R18, and resistor R15, turns on transistor Q11, thereby turning on field effect tube Q9, and the DC power conversion module is connected to the voltage output terminal VOUT. The other path passes through C2, resistor R19, and resistor R16, turns on transistor Q12, thereby turning on field effect tube Q10 and outputting voltage. Here, the voltage across capacitor C2 cannot change suddenly, and capacitor C2 is equivalent to a short circuit, so that the input voltage VIN is output to resistor R18 and resistor R19, and the voltage output terminal VOUT is output, achieving normal output of the circuit. When capacitor C2 is charged for a certain time, the input voltage VIN is no longer output to resistor R18 and resistor R19, but the voltage output terminal VOUT has output at this time; the output of the voltage output terminal VOUT is divided to point A by resistor R17 and resistor R20, turning on transistor Q11, field effect tube Q9, transistor Q12, and field effect tube Q10, achieving continuous output, and completing the self-locking function. If the voltage output terminal VOUT is short-circuited with the ground, the voltage at point A is 0V, transistors Q11 and Q12 are turned off, and thus field effect transistors Q9 and Q10 are turned off. At this time, the voltage output terminal VOUT is turned off, completing the short-circuit protection. After the short-circuit protection occurs, the circuit is restored by pressing the key switch K.

[0025] In the circuit, the switch function of the field effect tube Q9 is 1. to protect the input voltage VIN; 2. after a short circuit occurs, the field effect tube Q9 is turned off to reduce power consumption. The switch function of the field effect tube Q10 is to protect the subsequent circuit after a short circuit occurs.

[0026] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A short-circuit protection circuit for power output, characterized in that: include: One input voltage VIN is connected to the source S of the field effect transistor Q9, the gate G of the field effect transistor Q9 is connected to the collector c of the transistor Q11, and the base b of the transistor Q11 is connected to one end of the resistor R18; another input voltage VIN is connected to one end of the capacitor C2, and the other end of the capacitor C2 is respectively connected to the other end of the resistor R18 and one end of the resistor R19; the other end of the resistor R19 is connected to the base b of the transistor Q12, the collector c of the transistor Q12 is connected to the gate G of the field effect transistor Q10, and the drain D of the field effect transistor Q10 is connected to the voltage output terminal VOUT; the voltage output terminal VOUT is connected to one end of the resistor 17, the other end of the resistor R17 is connected to the resistor R20, and the other end of the resistor R20 is grounded; The switch circuit comprises: a key switch K connected in parallel with the capacitor C2; When a short circuit occurs, the voltage at the voltage output terminal VOUT is 0V, the capacitor C2 is equivalent to being disconnected, the input voltage VIN cannot supply power to the resistor R18 and the resistor R19, the transistor Q11 and the transistor Q12 are cut off, the field effect transistor Q9 and the field effect transistor Q10 are turned off, the input voltage VIN is cut off, and the entire circuit is protected; after the short circuit is canceled, the key switch K is pressed and the protection circuit is restarted.

2. A short-circuit protection circuit for power output as claimed in claim 1, characterized in that: It also includes a voltage divider circuit: one end of the resistor R15 is connected to the collector C pole of the transistor Q11, and the other end of the resistor R15 is connected to the source S pole of the field effect transistor Q9; one end of the resistor R16 is connected to the collector C pole of the transistor Q12, and the other end of the resistor R16 is connected to the source S pole of the field effect transistor Q10.

3. A short-circuit protection circuit for power output as claimed in claim 1, characterized in that: It also includes a control circuit: the switching of the transistor Q11 and the transistor Q12 is controlled by feedback from the voltage output terminal VOUT.

4. A short-circuit protection circuit for power output as claimed in claim 3, characterized in that: The emitter and the e-pole of the transistor Q11 are grounded, and the emitter and the e-pole of the transistor Q12 are grounded.

5. A short-circuit protection circuit for power output as claimed in claim 1, characterized in that: The drain D of the field effect transistor Q9 is connected to one end of the DC power conversion module, and the source S of the field effect transistor Q10 is connected to the other end of the DC power conversion module, so as to control the input voltage VIN to supply power to the subsequent circuit.

Images