Low-cost MOS (Metal Oxide Semiconductor) tube low-side driving circuit with overcurrent protection function

Abstract

The utility model provides a low-cost MOS tube low-side driving circuit with an overcurrent protection function, and belongs to the technical field of low-side driving circuits. The problem that protection lacks when a driving chip is adopted to carry out low-side driving on power equipment is solved. Comprising a driving circuit and a protection circuit, the driving circuit comprises a first MOS tube, a first resistor and a second resistor, a gate electrode of the first MOS tube is connected with a control signal through the first resistor, a source electrode of the first MOS tube is connected with an overcurrent protection circuit, a drain electrode of the first MOS tube is connected with output, one end of the second resistor is connected between the first resistor and the gate electrode of the first MOS tube, and the other end of the second resistor is directly grounded; the protection circuit comprises a second MOS tube, a first resistor and a third resistor, the gate electrode of the second MOS tube is connected between the source electrode of the first MOS tube and one end of the third resistor, the other end of the third resistor is grounded, the source electrode of the second MOS tube is directly grounded, and the drain electrode of the second MOS tube is connected between the first resistor and the gate electrode of the first MOS tube; the low-side driving circuit is applied to low-side driving.

Description

TECHNICAL FIELD

[0001] The utility model provides a low cost MOS pipe low side drive circuit with overcurrent protection function belongs to low side drive circuit technical field. BACKGROUND

[0002] At present, the new energy automobile industry develops rapidly. Many power electronic switching devices are used in new energy electric vehicles. Bottom edge drive circuit is needed to drive some power devices in vehicle control, such as high-speed cooling fan, warning light, horn, etc. At present, drive chip is widely used in the market to achieve the purpose of low side drive, but the drive chip itself does not have protection function. INVENTION CONTENTS

[0003] The utility model discloses in order to solve the problem that the low side drive of power device is short of protection when using drive chip, and proposes a low cost MOS pipe low side drive circuit with overcurrent protection function, which aims at realizing low cost and protection function of low side drive by using MOS pipe.

[0004] The technical scheme adopted by the utility model is as follows: a low cost MOS pipe low side drive circuit with overcurrent protection function, comprising a drive circuit and a protection circuit, the drive circuit comprises a first MOS pipe and a first resistance, a second resistance, the gate of the first MOS pipe is connected with a control signal through the first resistance, the source of the first MOS pipe is connected with an overcurrent protection circuit, the drain of the first MOS pipe is connected with an output, one end of the second resistance is connected between the first resistance and the gate of the first MOS pipe, and the other end is directly connected with the ground.

[0005] The protection circuit comprises an overcurrent protection circuit, the overcurrent protection circuit comprises a second MOS pipe, a first resistance and a third resistance, the gate of the second MOS pipe is connected between the source of the first MOS pipe and one end of the third resistance, the other end of the third resistance is connected with the ground, the source of the second MOS pipe is directly connected with the ground, and the drain of the second MOS pipe is connected between the first resistance and the gate of the first MOS pipe.

[0006] Further, the protection circuit further comprises an anti-static protection circuit.

[0007] Further, the anti-static protection circuit comprises an anti-static protection element, one end of the anti-static protection element is connected with the output, and the other end is connected with the ground.

[0008] Further, the anti-static protection element adopts an ESD diode.

[0009] Further, the first MOS pipe and the second MOS pipe both adopt N channel MOS pipe.

[0010] The low-cost MOS tube low-side drive circuit with overcurrent protection function has the advantages that low-side drive and overcurrent protection of power equipment are simultaneously realized by adopting two NMOS tubes, a drive chip is not needed, cost is low, and the low-cost MOS tube low-side drive circuit with overcurrent protection function further has an anti-static protection function and can guarantee reliable operation of the circuit. BRIEF DESCRIPTION OF DRAWINGS

[0011] The utility model makes further explanation from the following combined with the drawing:

[0012] Figure 1 It is the circuit principle drawing of the utility model. DETAILED DESCRIPTION

[0013] As Figure 1 shown, the utility model provides a low-cost MOS tube low-side drive circuit with overcurrent protection function, including drive circuit and protection circuit two parts, wherein the protection circuit includes anti-static protection circuit and overcurrent protection circuit, the drive circuit includes first MOS tube and first resistance, second resistance, the gate of first MOS tube passes through the first resistance and connects control signal, the source of first MOS tube connects overcurrent protection circuit, the drain of first MOS tube connects output, one end of second resistance connects between first resistance and the gate of first MOS tube, the other end directly connects ground.

[0014] The anti-static protection circuit includes an anti-static protection element, one end of the anti-static protection element is connected to the output terminal, and the other end of the anti-static protection element is grounded.

[0015] The overcurrent protection circuit includes a second MOS tube, a first resistance and a third resistance, the gate of the second MOS tube is connected between the source of the first MOS tube and one end of the third resistance, the other end of the third resistance is grounded, the source of the second MOS tube is directly grounded, and the drain of the second MOS tube is connected between the first resistance and the gate of the first MOS tube.

[0016] According to Figure 1 shown, in the embodiment, the first MOS tube is MOS tube Q1, the first resistance is resistor R1, the second resistance is resistor R2, the anti-static protection element is ESD protection element Q2, which is a static protection element and is used for realizing anti-static protection function, the second MOS tube is MOS tube Q3, and the third resistance is resistor R3, wherein the resistor R1 is a current-limiting resistor, the resistor R2 is a pull-down resistor, the resistor R3 is a sampling resistor, the MOS tube Q1 is a drive MOS tube, and the MOS tube Q3 is a protection MOS tube.

[0017] One end of the current-limiting resistor R1 is connected with the control end of the power device, the other end of the current-limiting resistor R1 is connected with one end of the pull-down resistor R2, the D pole of the protection MOS Q3 and the G pole of the driving MOS Q1 in parallel, the other end of the pull-down resistor R2 is connected with the S pole of the protection MOS Q3 in parallel and then connected to the GND, the G pole of the protection MOS Q3 is connected with one end of the sampling resistor R3 and the S pole of the driving MOS Q1 in parallel, the other end of the sampling resistor R3 is connected with the GND, the D pole of the driving MOS Q1 is connected with the 1 and 2 pins of the ESD protection element Q2 in parallel and then connected to the OUT end, and the 3 pin of the ESD protection element Q2 is connected with the GND.

[0018] The principle of the utility model is as follows:

[0019] When the control signal enters, the gate voltage of the driving MOS Q1 is greater than the gate-source voltage, the drain and the source are turned on, the drain reaches the grounding effect, and the low-side control function is completed; the current-limiting resistor R1 reduces the current when the control voltage is input, the pull-down resistor R2 plays a voltage dividing role, and the two resistors jointly avoid the driving MOS Q1 from being broken down due to excessive current.

[0020] When the control signal enters, the source and the drain of the driving MOS Q1 are turned on, if the OUT end is short-circuited at this time, the gate voltage of the protection MOS Q3 will be greater than the gate-source voltage, the source and the drain of the protection MOS Q3 will be turned on, the gate voltage of the driving MOS Q1 is pulled down, the gate voltage of the driving MOS Q1 is no longer greater than the gate-source voltage, the drain and the source are turned off, and the external short power supply cannot enter the circuit, thereby playing a protection role. Further, when the source-drain of the driving MOS Q1 is short-circuited, the sampling resistor R3 acts as a load to avoid the external power supply from being directly grounded; at the same time, when the source and the drain of the protection MOS Q3 are turned on, the current-limiting resistor R1 acts as a load to avoid the control signal from being directly grounded.

[0021] It should be noted that the connection relationship between the various component modules of the utility model is determined and can be realized, and the specific connection relationship can bring corresponding technical effects, and based on the premise of not relying on the execution of the corresponding software program, the technical problems proposed in the utility model are solved, the model, the connection mode between the components, the modules and the specific components, and the conventional use method and the expected technical effect brought by the above technical features, except for the specific description, all belong to the public content disclosed in the patents, journal papers, technical manuals, technical dictionaries, textbooks and other existing technologies obtained by the applicant before the application date, or to the conventional technology and common knowledge in the field, and do not need to be described in detail, so that the technical scheme provided in the case is clear, complete and can be realized, and the corresponding entity product can be reproduced or obtained according to the technical means.

[0022] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A low-cost MOSFET low-side driver circuit with overcurrent protection, characterized by: The driving circuit comprises a first MOS tube and a first resistor and a second resistor, the gate of the first MOS tube is connected to a control signal through the first resistor, the source of the first MOS tube is connected to an overcurrent protection circuit, the drain of the first MOS tube is connected to an output, one end of the second resistor is connected between the first resistor and the gate of the first MOS tube, and the other end of the second resistor is directly connected to the ground; The protection circuit comprises an overcurrent protection circuit, the overcurrent protection circuit comprises a second MOS tube, a first resistor and a third resistor, the gate of the second MOS tube is connected between the source of the first MOS tube and one end of the third resistor, the other end of the third resistor is connected to the ground, the source of the second MOS tube is directly connected to the ground, and the drain of the second MOS tube is connected between the first resistor and the gate of the first MOS tube.

2. The low-cost MOSFET low-side driver circuit with overcurrent protection according to claim 1, wherein: The protection circuit further comprises an anti-static protection circuit.

3. The low-cost MOSFET low-side driver circuit with overcurrent protection according to claim 2, wherein: The anti-static protection circuit comprises an anti-static protection element, one end of the anti-static protection element is connected to the output, and the other end of the anti-static protection element is connected to the ground.

4. The low-cost MOSFET low-side driver circuit with overcurrent protection according to claim 3, wherein: The anti-static protection element is an ESD diode.

5. The low-cost MOSFET low-side driver circuit with overcurrent protection according to any one of claims 1-4, characterized in that: The first MOS tube and the second MOS tube are both N-channel MOS tubes.

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