Short circuit protection circuit and power supply device

Abstract

The application discloses a short-circuit protection circuit and a power supply device. The short-circuit protection circuit is applicable to the power supply device including a power output terminal and a power ground terminal, and comprises an inductor, first and second switch units, a current-limiting resistor and a voltage stabilizing circuit. One end of the inductor is connected with a system ground; the first switch unit is connected with the other end of the inductor and the power ground terminal; one end of the current-limiting resistor is connected with the power ground terminal; the second switch unit is connected with the other end of the current-limiting resistor, the system ground and the first switch unit; and the voltage stabilizing circuit is connected between the inductor and the first switch unit, between the first and second switch units and the power output terminal. When the power output terminal is powered, the voltage stabilizing circuit turns on the first switch unit and turns off the second switch unit, so that the system ground and the power ground terminal are turned on; when a short circuit occurs, a short-circuit current occurs at the power ground terminal and flows through the current-limiting resistor to the second switch unit, the second switch unit is turned on, the first switch unit is turned off, and the inductor is isolated from the system ground and the power ground terminal.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, specifically to a short-circuit protection circuit and a power supply device. Background Technology

[0002] Currently, the requirements for the reliability and safety of power supply equipment are becoming increasingly stringent. Therefore, power supply equipment needs to be equipped with short-circuit protection circuits to comply with safety regulations and enhance the protection of the power supply equipment.

[0003] Existing short-circuit protection circuits typically use software protection methods, where a dedicated chip processes and judges the acquired signals before performing subsequent control and operation. This method requires sophisticated design and suffers from high cost and slow response time. Summary of the Invention

[0004] This application provides a short-circuit protection circuit and a power supply device, which can solve the problems of high cost and slow response time of existing short-circuit protection circuits, which usually adopt software protection methods.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] This application provides a short-circuit protection circuit applicable to a power supply device, which includes a power output terminal and a power ground terminal for external power supply. The short-circuit protection circuit includes an inductor, a first switching unit, a second switching unit, a current-limiting resistor, and a voltage regulator circuit. One end of the inductor is connected to system ground; the first switching unit is connected to the other end of the inductor and the power ground terminal; one end of the current-limiting resistor is connected to the power ground terminal; the second switching unit is connected to the other end of the current-limiting resistor, system ground, and the first switching unit; the voltage regulator circuit is connected to the connection point between the other end of the inductor and the first switching unit, the connection point between the first and second switching units, and the power output terminal. When the power output terminal is energized, the voltage regulator circuit turns on the first switching unit and turns off the second switching unit, making the system ground and power ground terminal connected, and the short-circuit protection circuit is in normal operating condition. When a short circuit occurs between the power output terminal and the power ground terminal, a short-circuit current occurs at the power ground terminal and flows through the current-limiting resistor to the second switching unit, causing the second switching unit to turn on, thereby turning off the first switching unit. The inductor isolates the system ground and the power ground terminal.

[0007] This application provides a power supply device, which includes: a power output terminal and a power ground terminal for external power supply, and a short-circuit protection circuit of this application.

[0008] In this embodiment, short-circuit protection is achieved through the configuration of an inductor, a first switching unit, a second switching unit, a current-limiting resistor, and a voltage regulator circuit (i.e., through hardware protection). This method is simple, reliable, and faster than software-based short-circuit protection, while also being cheaper than using dedicated chips. Furthermore, the short-circuit protection circuit in this embodiment can be adapted to power supply devices providing different power outputs by simply adjusting the parameters of the inductor and the first switching unit, offering flexibility and strong adaptability. Attached Figure Description

[0009] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are configured to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0010] Figure 1 A schematic diagram of an embodiment of a power supply device using the short-circuit protection circuit of this application;

[0011] Figure 2 A schematic diagram of the circuit structure of a power supply device that applies the short-circuit protection circuit of this application;

[0012] Figure 3 A schematic diagram of the circuit structure of another embodiment of a power supply device applying the short-circuit protection circuit of this application; and

[0013] Figure 4 A schematic diagram of the circuit structure of another embodiment of a power supply device using the short-circuit protection circuit of this application. Detailed Implementation

[0014] The embodiments of the present invention will be described below with reference to the accompanying drawings. In these drawings, the same reference numerals denote the same or similar components or method flows.

[0015] It must be understood that the use of terms such as "comprising" or "including" in this specification is configured to indicate the presence of specific technical features, values, method steps, work processes, and / or components, but does not preclude the addition of more technical features, values, method steps, work processes, components, or any combination thereof.

[0016] It is important to understand that when a component is described as "connected" or "coupled" to another component, it can be a direct connection or coupling to other components, and there may be intermediate components. Conversely, when a component is described as "directly connected" or "directly coupled" to another component, there are no intermediate components.

[0017] Please see Figure 1This is a schematic diagram of an embodiment of a power supply device using the short-circuit protection circuit of this application. Figure 1 As shown, the short-circuit protection circuit 1 is applicable to the power supply device 2. The power supply device 2 includes a power output terminal VB for external power supply and a power ground terminal PGND. The power supply device 2 can be, but is not limited to, a power adapter. The short-circuit protection circuit 1 includes an inductor 11, a first switching unit 12, a second switching unit 13, a current-limiting resistor 14, and a voltage regulator circuit 15. One end of the inductor 11 is connected to the system ground GND; the first switching unit 12 is connected to the other end of the inductor 11 and the power ground terminal PGND; one end of the current-limiting resistor 14 is connected to the power ground terminal PGND; the second switching unit 13 is connected to the other end of the current-limiting resistor 14, the system ground GND, and the first switching unit 12; the voltage regulator circuit 15 is connected to the connection point P1 between the other end of the inductor 11 and the first switching unit 12, the connection point P2 between the first switching unit 12 and the second switching unit 13, and the power output terminal VB.

[0018] The voltage regulator circuit 15 is used to turn on the first switching unit 12 and turn off the second switching unit 13 when the power output terminal VB is energized, so that the system ground GND and the power ground terminal PGND are connected, and the short-circuit protection circuit 1 is in normal working condition. Specifically, when the power output terminal VB is energized, the voltage regulator circuit 15 provides a high level to the first switching unit 12, so that the first switching unit 12 is turned on, and at this time the second switching unit 13 is turned off. All components between the system ground GND and the power ground terminal PGND are connected (i.e., the system ground GND and the power ground terminal PGND are connected; that is, the power ground terminal PGND and the system ground GND share a common ground), the short-circuit protection circuit 1 is in normal working condition, and the power supply device 2 supplies power to the outside normally.

[0019] When a short circuit occurs between the power output terminal VB and the power ground terminal PGND, a short circuit current occurs at the power ground terminal PGND. The short circuit current flows through the current limiting resistor 14 to the second switching unit 13, causing the second switching unit 13 to conduct, thereby turning off the first switching unit 12. The inductor 11 is used to isolate the system ground GND and the power ground terminal PGND, and the short circuit protection circuit 1 is in a short circuit protection state. Specifically, when a short circuit occurs between the power output terminal VB and the power ground terminal PGND (equivalent to the power output terminal VB and the power ground terminal PGND being connected together; that is, the voltage of the power ground terminal PGND is momentarily the same as the voltage of the power output terminal VB), the short-circuit current flows through the current-limiting resistor 14 to the second switching unit 13, causing the second switching unit 13 to conduct, thereby providing a low level to the first switching unit 12 and turning off the first switching unit 12, achieving the function of short-circuit protection. At this time, the current-limiting resistor 14 is used to limit the current flowing into the second switching unit 13, so as to reduce the possibility of damage to the second switching unit 13 due to excessive current, indirectly improving its service life. The inductor 11 is used to isolate the system ground GND and the power ground terminal PGND. That is, when the short-circuit protection circuit 1 is in the short-circuit protection state, the power ground terminal PGND and the system ground GND are isolated by the inductor 11, and the power ground terminal PGND and the system ground GND are independent grounding points that do not interfere with each other.

[0020] In one embodiment, the first switching unit 12 may be an NMOS transistor, the drain D1 of which is connected to the power ground terminal PGND, the gate G1 of which is connected to the collector C1 of the second switching unit 13, and the source S1 of which is connected to the other end of the inductor 11 (e.g., Figure 2 As shown, Figure 2 This is a schematic diagram of a circuit structure for a power supply device using the short-circuit protection circuit of this application. When the gate G1 of the NMOS transistor is at a high level (i.e., the short-circuit protection circuit 1 is in normal operation), the NMOS transistor is in the on state (i.e., the first switching unit 12 is on); when the gate G1 of the NMOS transistor is at a low level (i.e., the short-circuit protection circuit 1 is in short-circuit protection state), the NMOS transistor is in the off state (i.e., the first switching unit 12 is off).

[0021] In one embodiment, the second switching unit 13 may be an NPN transistor, with its emitter E1 connected to system ground GND, its base B1 connected to the other end of the current-limiting resistor 14, and its collector C1 connected to the gate G1 of the first switching unit 12 (e.g., the gate of the first switching unit 12). Figure 2 (As shown).

[0022] In one embodiment, the voltage regulator circuit 15 may include a Zener diode 151 and a voltage regulator resistor 152. One end of the voltage regulator resistor 152 is connected to the power output terminal VB, and the other end of the voltage regulator resistor 152 is connected to the connection point P2 between the cathode of the Zener diode 151 and the first switching unit 12 and the second switching unit 13. The anode of the Zener diode 151 is connected to the connection point P1 between the other end of the inductor 11 and the first switching unit 12 (e.g., ...). Figure 2 (As shown).

[0023] In one embodiment, the short-circuit protection circuit 1 may further include a first resistor 16, which is disposed between the first switching unit 12 and the power ground terminal PGND. The first resistor 16 is used to adjust the sensitivity of current detection during normal operation of the short-circuit protection circuit 1. By detecting the voltage of the loop composed of the first resistor 16, the first switching unit 12, and the inductor 11, the actual current magnitude (e.g., ...) is calculated by the microcontroller unit 19. Figure 3 As shown, Figure 3 (A schematic diagram of the circuit structure of another embodiment of a power supply device using the short-circuit protection circuit of this application).

[0024] In one embodiment, the short-circuit protection circuit 1 may further include a plurality of first resistors 16, which are connected in parallel and disposed between the first switching unit 12 and the power ground terminal PGND. The plurality of first resistors 16 are used to adjust the sensitivity of the short-circuit protection circuit 1 (e.g., Figure 4 As shown, Figure 4 (A schematic diagram of the circuit structure of another embodiment of the power supply device using the short-circuit protection circuit of this application). The number of first resistors 16 may be, but is not limited to, two, and the resistance values ​​of the multiple first resistors 16 may be the same or different.

[0025] In one embodiment, the short-circuit protection circuit 1 may further include a discharge diode 17, which is connected in parallel with the inductor 11. The cathode of the discharge diode 17 is connected to the connection point P1 between the other end of the inductor 11 and the first switching unit 12, and the anode of the discharge diode 17 is connected to the system ground GND. The discharge diode 17 is used to provide a discharge path for the inductor 11 when a short circuit occurs between the power output terminal VB and the power ground terminal PGND (e.g., when a short circuit occurs between the power output terminal VB and the power ground terminal PGND). Figures 3 to 4 (As shown).

[0026] In one embodiment, when the power output terminal VB is not a controlled terminal, the power output terminal VB can be automatically restored to power, so that the short circuit protection circuit 1 can be restored from the short circuit protection state to the normal working state.

[0027] In one embodiment, when the power output terminal VB is a controlled terminal, when a short circuit occurs between the power output terminal VB and the power ground terminal PGND, the first switching unit 12 is turned on, causing the second switching unit 13 to turn off, and the power output terminal VB is controlled to be de-energized; the short circuit protection circuit 1 can also connect a third switching unit 18 and a microcontroller unit 19; the third switching unit 18 is connected to the other end of the current limiting resistor 14, the connection point P3 between the second switching unit 13 and the system ground GND, and the microcontroller unit 19; the microcontroller unit 19 is connected to the connection point P2 between the first switching unit 12 and the second switching unit 13 and the power output terminal VB; the microcontroller unit 19 is used to send a pulse signal to the third switching unit 18 when it detects that the first switching unit 12 is turned off, so as to turn on the third switching unit 18, thereby turning off the second switching unit 13, and then turning on the first switching unit 12, controlling the power output terminal VB to be energized again, so that the short circuit protection circuit 1 returns to the normal operating state (e.g., Figure 3 (As shown). Specifically, when the microcontroller unit 19 detects that the gate G1 of the first switching unit 12 is at a low level (i.e., the short-circuit protection circuit 1 is in a short-circuit protection state), it sends a pulse signal to the third switching unit 18 to turn on the third switching unit 18, thereby not providing current to the base B1 of the second switching unit 13 and turning off the second switching unit 13, and then providing a high level to the gate G1 of the first switching unit 12 to turn on the first switching unit 12, and controlling the power output terminal VB to resume power supply, so that the short-circuit protection circuit 1 returns to the normal operating state.

[0028] In one embodiment, the third switching unit 18 may be an NPN transistor, with its emitter E2 connected to system ground GND, its base B2 connected to the microcontroller unit 19, and its collector C2 connected to the other end of the current-limiting resistor 14 and the connection point P3 between the second switching unit 13 (e.g., ...). Figure 3 (As shown).

[0029] In one embodiment, the microcontroller unit 19 can be connected to the power ground terminal PGND to detect the resistance value of the loop formed by the first switching unit 12 and the inductor 11 through the power ground terminal PGND when the short-circuit protection circuit 1 is in the normal operating state (i.e., the power supply device 2 is normally supplying power to the outside), so as to calculate and obtain the system current (e.g., when the short-circuit protection circuit 1 is in the normal operating state (i.e., the power supply device 2 is normally supplying power to the outside)). Figure 2 (As shown). By adjusting the resistance values ​​of the first switching unit 12 and the inductor 11 in this circuit, the short-circuit protection circuit 1 can be adapted to applications with different detection system current ranges and to power supply devices 2 that provide different power outputs. It should be noted that the inductance value of the inductor 11 is directly proportional to the sensitivity of the short-circuit protection circuit 1 and the magnitude of the system current.

[0030] In one embodiment, the microcontroller unit 19 can be connected to the power ground terminal PGND to detect the resistance value of the loop composed of the first switching unit 12, the inductor 11, and the first resistor 16 / multiple first resistors 16 when the short-circuit protection circuit 1 is in the normal operating state, so as to calculate and obtain the system current (e.g., Figure 3 and Figure 4 (As shown).

[0031] In summary, short-circuit protection is achieved through the configuration of an inductor, a first switching unit, a second switching unit, a current-limiting resistor, and a voltage regulator circuit (i.e., through hardware protection). This method is simple, reliable, and faster than software-based short-circuit protection, while also being less expensive than using dedicated chips. Furthermore, the short-circuit protection circuit in this embodiment can be easily adapted to power supply devices providing different power outputs and to applications with varying current ranges in different detection systems by simply adjusting the parameters of the inductor, the first switching unit, and / or the first resistor. This flexibility and adaptability are significant advantages.

[0032] While the present invention has been described using the above embodiments, it should be noted that these descriptions are not intended to limit the invention. Rather, this invention encompasses modifications and similar arrangements that will be obvious to those skilled in the art. Therefore, the scope of the claims should be interpreted in the broadest possible sense to include all obvious modifications and similar arrangements.

Claims

1. A short-circuit protection circuit, characterized in that, Applicable to power supply devices, the power supply device includes a power output terminal and a power ground terminal for external power supply, including: An inductor, one end of which is connected to system ground; The first switching unit connects the other end of the inductor to the power ground terminal; A current-limiting resistor, one end of which is connected to the power ground terminal; The second switching unit is connected to the other end of the current-limiting resistor, the system ground, and the first switching unit; and A voltage regulator circuit is connected to the connection point between the other end of the inductor and the first switching unit, and the connection point between the first switching unit and the second switching unit and the power output terminal. The voltage regulator circuit is used to turn on the first switching unit and turn off the second switching unit when the power output terminal is energized, so that the system ground is connected to the power ground terminal. The short circuit protection circuit is in normal working condition. When a short circuit occurs between the power output terminal and the power ground terminal, a short circuit current occurs at the power ground terminal. The short circuit current flows through the current limiting resistor to the second switching unit, causing the second switching unit to conduct and thereby turning off the first switching unit. The inductor is used to isolate the system ground from the power ground terminal. In this configuration, the first switching unit is an NMOS transistor, the second switching unit is an NPN transistor, the drain of the NMOS transistor is connected to the power ground terminal, the source of the NMOS transistor is connected to the other end of the inductor, the emitter of the NPN transistor is connected to the system ground, the base of the NPN transistor is connected to the other end of the current limiting resistor, and the collector of the NPN transistor is connected to the gate of the NMOS transistor.

2. The short-circuit protection circuit according to claim 1, characterized in that, The voltage regulator circuit includes a Zener diode and a voltage regulator resistor. One end of the voltage regulator resistor is connected to the power output terminal, and the other end of the voltage regulator resistor is connected to the cathode of the Zener diode and the connection point between the first switching unit and the second switching unit. The anode of the Zener diode is connected to the other end of the inductor and the connection point between the first switching unit.

3. The short-circuit protection circuit according to claim 1, characterized in that, It also includes a discharge diode connected in parallel with the inductor; the cathode of the discharge diode is connected to the connection point between the other end of the inductor and the first switching unit, and the anode of the discharge diode is connected to the system ground; the discharge diode is used to provide a discharge circuit for the inductor when a short circuit occurs between the power output terminal and the power ground terminal.

4. The short-circuit protection circuit according to claim 1, characterized in that, It also includes a first resistor, disposed between the first switching unit and the power ground terminal, for adjusting the sensitivity of the short-circuit protection circuit.

5. The short-circuit protection circuit according to claim 1, characterized in that, It also includes a third switching unit and a microcontroller unit; the third switching unit is connected to the connection point between the other end of the current-limiting resistor and the second switching unit, the system ground, and the microcontroller unit; the microcontroller unit is connected to the connection point between the first switching unit and the second switching unit and the power output terminal; when a short circuit occurs between the power output terminal and the power ground terminal, the first switching unit is turned on, causing the second switching unit to turn off, and the power output terminal is controlled to be de-energized; the microcontroller unit is used to detect when the first switching unit is turned off, send a pulse signal to the third switching unit to turn on the third switching unit, thereby turning off the second switching unit, and then turning on the first switching unit to control the power output terminal to be energized again, so that the short-circuit protection circuit returns to the normal operating state.

6. The short-circuit protection circuit according to claim 5, characterized in that, The third switching unit is an NPN transistor. The emitter of the NPN transistor is connected to the system ground, the base of the NPN transistor is connected to the microcontroller unit, and the collector of the NPN transistor is connected to the connection point between the other end of the current-limiting resistor and the second switching unit.

7. The short-circuit protection circuit according to claim 5, characterized in that, The microcontroller unit is connected to the power ground terminal so that when the short-circuit protection circuit is in the normal operating state, it can detect the resistance value of the loop formed by the first switching unit and the inductor through the power ground terminal to calculate and obtain the system current.

8. The short-circuit protection circuit according to claim 5, characterized in that, It also includes a first resistor, disposed between the first switching unit and the power ground terminal, for adjusting the sensitivity of the short-circuit protection circuit.

9. The short-circuit protection circuit according to claim 8, characterized in that, The microcontroller unit is connected to the power ground terminal to detect the resistance value of the loop formed by the first switching unit, the inductor and the first resistor through the power ground terminal, so as to calculate and obtain the system current.

10. A power supply device, characterized in that, include: The power output terminal and power ground terminal for external power supply, and the short-circuit protection circuit as described in any one of claims 1 to 9.

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