Overcurrent protection circuit applied to MOSFET drive

Abstract

The utility model relates to an over-current protection circuit applied to MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) driving, aiming at improving the over-current protection response speed, reducing the power consumption and providing a visual early warning function. The circuit is composed of a driving circuit, an over-current protection circuit and a voltage stabilizing circuit. The drive circuit is controlled by PWM signals, and rapid on and off of an MOS tube are achieved through a PNP type triode. The overcurrent protection circuit takes a Hall sensor as a core, detects current in real time and outputs a signal, and is matched with an MOS tube to realize circuit cut-off during overload. The voltage stabilizing circuit provides stable working voltage through a linear voltage stabilizer. Compared with a traditional over-current protection scheme, the circuit utilizes the Hall sensor to directly detect current, extra power consumption is avoided, and the detection precision is improved. The protection circuit rapidly cuts off a main current path during overload, and provides an early warning prompt through an LED. The design has the advantages of high response speed and low energy consumption.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, specifically to an overcurrent protection circuit applied to MOSFET driving. Background Technology

[0002] The most economical and convenient method for overcurrent protection is using fuses. However, this method has the disadvantage of frequent fuse replacements, which is inconvenient. Therefore, overcurrent protection circuits are used in various scenarios requiring current protection to ensure the safe operation of equipment. However, current overcurrent protection circuits that use comparators to detect current generally suffer from delayed feedback on MOSFET overcurrent conditions. This can lead to the circuit not responding quickly enough to overcurrent situations, potentially damaging the equipment. Furthermore, many protection circuits use sensing resistors for current detection. While this method is simple and easy to implement, it inevitably increases power consumption, thus reducing the overall system efficiency.

[0003] Therefore, improving circuit feedback speed, reducing power consumption, and providing visual alarm functions are urgent problems to be solved in the current technology field. Utility Model Content

[0004] This invention proposes an overcurrent protection circuit based on a Hall sensor, which can effectively improve the response speed of overcurrent protection, reduce power loss, and integrate early warning and protection functions.

[0005] To achieve the objectives of this utility model, the present invention adopts the following solution:

[0006] An overcurrent protection circuit for MOSFET driving includes a driving circuit, an overcurrent protection circuit, and a voltage regulator circuit.

[0007] The power supply terminal of the drive circuit is connected to the input power supply, the control terminal of the drive circuit is connected to the PWM control signal input, and the output terminal of the drive circuit is connected to the control terminal of the overcurrent protection circuit; the power supply terminal of the overcurrent protection circuit is connected to the output terminal of the voltage regulator circuit, the input terminal of the overcurrent protection circuit is connected to the output terminal of the line to be protected, and the PWM control terminal of the overcurrent protection circuit is connected to the PWM control signal input; the input terminal of the voltage regulator circuit is connected to the input power supply.

[0008] Furthermore, the driving circuit includes a MOSFET driver chip U1, resistors R1 and R2, a fast recovery diode D1, and a transistor Q2. The positive input terminal of the MOSFET driver chip U1 is connected to the PWM control signal input, the negative input terminal is connected to the ground terminal and grounded, the power supply terminal is connected to the input power supply, and the first output pin and the second output pin are connected to the positive terminal of the fast recovery diode D1 after being connected in series with resistors R1 and R2, respectively. The negative terminal of the fast recovery diode D1 is connected to the emitter of the transistor Q2 and the control terminal of the overcurrent protection circuit. The base of the transistor Q2 is connected to the positive terminal of the fast recovery diode D1, and the collector is grounded. The transistor Q2 is a PNP type transistor.

[0009] Furthermore, the overcurrent protection circuit includes a MOSFET Q1, a Hall sensor chip U2, a capacitor C1, a resistor R3, and a light-emitting diode LED1. The gate of the MOSFET Q1 is connected to the output terminal of the driving circuit, the drain is connected to the output terminal of the circuit to be protected, and the source is connected to the current detection input terminal of the Hall sensor chip U2. The current detection output terminal and the ground terminal of the Hall sensor chip U2 are connected together and grounded. The power supply terminal is connected to the output terminal of the voltage regulator circuit and one end of the capacitor C1, and the output terminal is connected to one end of the resistor R3. The other end of the resistor R3 is connected to the gate of the MOSFET Q3. The drain of the MOSFET Q3 is connected to the PWM control signal input, the source is connected to the positive terminal of the light-emitting diode LED1, and the negative terminal of the light-emitting diode LED1 is grounded.

[0010] Preferably, both MOS transistors Q2 and Q3 are N-type MOS transistors.

[0011] Furthermore, the voltage regulator circuit is a linear voltage regulator U3. The input terminal of the linear voltage regulator U3 is connected to the input power supply, and the output terminal and the output terminal are connected in a common circuit to provide a stable voltage output to the overcurrent protection circuit. The ground terminal is grounded.

[0012] Compared with the prior art, the technical solution of this utility model has the following beneficial effects:

[0013] The Hall sensor directly detects and outputs the current signal, which, together with the MOSFET, directly cuts off the circuit that is overloaded when there is a current overload, achieving a fast response and avoiding the energy consumption problem of traditional detection resistors. When the overcurrent protection circuit triggers the overload protection, it activates the LED1 to provide a real-time visual alarm prompt. Attached Figure Description

[0014] Figure 1 This is a circuit schematic diagram of an embodiment of the present invention.

[0015] In the above figures: 1-Drive circuit; 2-Overcurrent protection circuit; 3-Voltage regulator circuit; U1-MOSFET driver chip; R1-Resistor; R2-Resistor; D1-Fast recovery diode; Q2-Transistor; Q1-MOS transistor; U2-Hall sensor chip; C1-Capacitor; R3-Resistor; Q3-MOS transistor; LED1-Light emitting diode; U3-Linear regulator. Detailed Implementation

[0016] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings. These exemplary embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make the utility model more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. Throughout, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the invention, and should not be construed as limiting the invention.

[0017] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection", and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0018] The circuit schematic of this embodiment is as follows: Figure 1 As shown, the circuit includes a drive circuit 1, an overcurrent protection circuit 2, and a voltage regulator circuit 3. The drive circuit includes a MOSFET driver chip U1, resistors R1 and R2, a fast recovery diode D1, and a transistor Q2. Specifically, in this embodiment, the MOSFET driver chip U1 is model 1EDN7511B. The positive input terminal IN+ of the MOSFET driver chip U1 is connected to the PWM control signal input, and the negative input terminal IN- is connected to the ground terminal GND and grounded. The power supply terminal VDD is connected to the 10V input voltage. The first output pin OUT_SRC and the second output pin OUT_SNK are connected in series with resistors R1 and R2, respectively, and then connected to the positive terminal of the fast recovery diode D1. The negative terminal of the fast recovery diode D1 is connected to the emitter of the transistor Q2 and the control terminal of the overcurrent protection circuit. The base of the transistor Q2 is connected to the positive terminal of the fast recovery diode D1, and the collector is grounded. The transistor Q2 is a PNP type transistor.

[0019] The overcurrent protection circuit 2 includes a MOSFET Q1, a Hall sensor chip U2, a capacitor C1, a resistor R3, and a light-emitting diode LED1. The gate of the MOSFET Q1 is connected to the output terminal of the drive circuit 1, i.e., the negative terminal of the fast recovery diode D1. The drain is connected to the external input current, and the source is connected to the current detection input terminal IP+ of the Hall sensor chip U2. In this embodiment, the Hall sensor chip is model CC6920. The current detection output terminal IP- of the Hall sensor chip U2 and the ground terminal GND are connected together and grounded. The power supply terminal VCC is connected to the 5V voltage input output from the voltage regulator circuit and one end of the capacitor C1. The output terminal is connected to one end of the resistor R3. The other end of the resistor R3 is connected to the gate of the MOSFET Q3. The drain of the MOSFET Q3 is connected to the PWM control signal input, and the source is connected to the positive terminal of the light-emitting diode LED1. The negative terminal of the light-emitting diode LED1 is grounded. Both the MOSFET Q2 and the MOSFET Q3 are N-type MOSFETs.

[0020] In this embodiment, the voltage regulator circuit 3 is a linear regulator U3, model AMS1117-5.0. The input terminal VIN of the linear regulator U3 is connected to a 10V voltage input, and the output terminals VOUT and TAB are connected together to provide a stable voltage output of 5V to the overcurrent protection circuit 2. The ground terminal GND is grounded.

[0021] The overcurrent protection principle of this embodiment is as follows: The MOSFET driver chip U1 is controlled by the PWM control signal to output high and low levels to control the switching of transistor Q2 and MOSFET Q1. When the output of the MOSFET driver chip U1 is high, MOSFET Q1 is turned on, the base voltage of transistor Q2 is higher than the emitter voltage, and transistor Q2 is turned off. When the output of the MOSFET driver chip U1 is low, MOSFET Q1 is turned off. Due to the unidirectional conduction of the fast recovery diode D1, the gate of MOSFET Q1 retains a certain voltage. Therefore, the base voltage of transistor Q2 is less than the emitter voltage, transistor Q2 is turned on, the gate of MOSFET Q1 discharges rapidly, and Q1 is turned off, thereby cutting off the main current path. When the output of the MOSFET driver chip U1 is low, the conduction of transistor Q2 allows the gate of MOSFET Q1 to be grounded and discharged, which can quickly pull down the gate voltage and shut down the circuit where current overload occurs.

[0022] Hall sensor chip U2 detects the current flowing through MOSFET Q1. Once the current exceeds a set threshold, Hall sensor chip U2 outputs a voltage to the gate of MOSFET Q3 through its output pin OUT. The PWM signal line is grounded through MOSFET Q3, short-circuiting the positive input terminal IN+ of MOSFET driver chip U1. Simultaneously, LED1 illuminates to indicate that the current exceeds the threshold. At this time, MOSFET driver chip U1 will no longer output a signal, MOSFET Q1 will turn off, and LED1 will illuminate, indicating an overcurrent. The Hall sensor directly detects and outputs the current signal, working with the MOSFET to directly cut off the overcurrent circuit. Overcurrent protection is triggered by short-circuiting the driver circuit, directly pulling the current path to zero potential. Compared to traditional overcurrent protection circuits that rely on the driver circuit to provide sufficient drive voltage to the MOSFET gate to turn it on or off, this provides a faster response. The Hall sensor also avoids the energy consumption problem of traditional detection resistors. Activating the LED provides real-time visual prompts, allowing users to quickly identify problems.

[0023] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An overcurrent protection circuit for MOSFET driving, characterized in that, Includes drive circuit, overcurrent protection circuit and voltage regulator circuit; The power supply terminal of the drive circuit is connected to the input power supply, the control terminal of the drive circuit is connected to the PWM control signal input, and the output terminal of the drive circuit is connected to the control terminal of the overcurrent protection circuit. The power supply terminal of the overcurrent protection circuit is connected to the output terminal of the voltage regulator circuit, the input terminal of the overcurrent protection circuit is connected to the output terminal of the line to be protected, and the PWM control terminal of the overcurrent protection circuit is connected to the PWM control signal input. The input terminal of the voltage regulator circuit is connected to the input power supply.

2. The overcurrent protection circuit for MOSFET driving according to claim 1, characterized in that, The driving circuit includes a MOSFET driver chip U1, resistors R1 and R2, a fast recovery diode D1, and a transistor Q2; The positive input terminal of the MOSFET driver chip U1 is connected to the PWM control signal input, the negative input terminal is connected to the ground terminal and grounded, the power supply terminal is connected to the input power supply, and the first output pin and the second output pin are connected to the positive terminal of the fast recovery diode D1 after being connected in series with resistors R1 and R2 respectively. The negative terminal of the fast recovery diode D1 is connected to the emitter of the transistor Q2 and the control terminal of the overcurrent protection circuit; The base of transistor Q2 is connected to the positive terminal of fast recovery diode D1, and the collector is grounded; The transistor Q2 is a PNP type transistor.

3. The overcurrent protection circuit for MOSFET driving according to claim 1, characterized in that, The overcurrent protection circuit includes a MOSFET Q1, a Hall sensor chip U2, a capacitor C1, a resistor R3, a MOSFET Q3, and a light-emitting diode LED1; The gate of the MOS transistor Q1 is connected to the output terminal of the driving circuit, the drain is connected to the output terminal of the circuit to be protected, and the source is connected to the current detection input terminal of the Hall sensor chip U2. The current detection output terminal and the ground terminal of the Hall sensor chip U2 are connected together and grounded. The power supply terminal is connected to the output terminal of the voltage regulator circuit and one end of the capacitor C1. The output terminal is connected to one end of the resistor R3. The other end of the resistor R3 is connected to the gate of the MOSFET Q3; the drain of the MOSFET Q3 is connected to the PWM control signal input, the source is connected to the positive terminal of the LED1, and the negative terminal of the LED1 is grounded.

4. The overcurrent protection circuit for MOSFET driving according to claim 3, characterized in that, Both MOSFETs Q2 and Q3 are N-type MOSFETs.

5. An overcurrent protection circuit for MOSFET driving according to claim 1, characterized in that, The voltage regulator circuit is a linear regulator U3. The input terminal of the linear regulator U3 is connected to the input power supply, and the output terminals are connected in a common configuration to provide a stable voltage output to the overcurrent protection circuit. The ground terminal is grounded.

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