Positive electrode anti-reverse protection circuit

Abstract

The utility model relates to an anode anti-reverse protection circuit comprising an initial end MOS tube T1, an anti-reverse MOS tube T2, a fast turn-off circuit, a control circuit and a bootstrap circuit. The drain electrode of the initial end MOS tube T1 is connected with bus voltage, the source electrode of the initial end MOS tube T1 is connected with the source electrode of the anti-reverse MOS tube T2, the quick turn-off circuit and the bootstrap circuit are connected with the grid electrode of the anti-reverse MOS tube T2, and the control circuit and the bootstrap circuit are connected with the grid electrode of the initial end MOS tube T1; the control circuit is used for controlling the working state of the initial end MOS tube T1, the bootstrap circuit is used for providing bias voltage for the initial end MOS tube T1 and the anti-reverse MOS tube T2, and the rapid turn-off circuit is used for rapidly turning off the anti-reverse MOS tube T2 when the bus voltage is negative voltage. According to the utility model, the boosted circuit formed by combining the semiconductor components is utilized to realize a positive pole anti-reverse function, and the quick response of anti-reverse connection and the stability of the system are improved.

Description

Technical Field

[0001] The utility model belongs to automobile hardware circuit design, in particular to a positive electrode anti-reverse protection circuit. Background Art

[0002] At present, most of the anti-reverse connection devices used in oil pumps mainly use negative pole anti-reverse connection. This method mainly connects a MOS tube in series with GND. Figure 1 As shown, this structure provides a certain degree of protection against reverse connection. This method is simple in structure and low in cost, but it will have a certain impact on the subsequent ground plane voltage difference, and will affect the stability of use as the load increases. This structure has the following problems: The MOS tube cannot guarantee the stable operation of the system above 20V. The voltage drop and other noise superimposed on the GND end of the MOS when running at high current cannot be removed by the positive filter inductor. When the MCU is not running, the leakage current is high, and the working mode of the voltage regulator diode needs to be ensured. Summary of the invention

[0003] The utility model provides a positive pole reverse protection circuit, which realizes the positive pole reverse protection function by utilizing a boost circuit composed of semiconductor components, thereby improving the rapid response of reverse connection protection and the stability of the system.

[0004] The technical solution of the utility model is as follows: a positive electrode anti-reverse protection circuit, comprising: an initial end MOS tube T1, an anti-reverse MOS tube T2, a fast shutdown circuit, a control circuit and a bootstrap circuit;

[0005] The drain of the initial end MOS tube T1 is connected to the bus voltage, the source of the initial end MOS tube T1 is connected to the source of the anti-reverse MOS, the fast shutdown circuit and the bootstrap circuit are connected to the gate of the anti-reverse MOS tube T2, and the control circuit and the bootstrap circuit are connected to the gate of the initial end MOS tube T1;

[0006] The control circuit is used to control the working state of the initial end MOS tube T1, the bootstrap circuit is used to provide bias voltage to the initial end MOS tube T1 and the anti-reverse MOS tube T2, and the fast shutdown circuit is used to quickly shut down the anti-reverse MOS tube T2 when the bus voltage is a negative voltage.

[0007] Further, the control circuit includes: a first resistor R1, a third resistor R3, a switch MOS tube T3, a Zener diode ZD1 and a seventh resistor R7, one end of the first resistor R1 is connected to the drain of the initial end MOS tube T1, the other end of the first resistor R1 is connected to the gate of the initial end MOS tube T1, one end of the third resistor R3 is connected to the gate of the initial end MOS tube T1, the other end of the third resistor R3 is connected to the drain of the switch MOS tube T3 and the cathode of the Zener diode ZD1, the anode of the Zener diode ZD1 and the source of the switch MOS tube T3 are connected to the signal ground, one end of the seventh resistor R7 is connected to the second control signal and the gate of the switch MOS tube T3, and the other end of the seventh resistor R7 is connected to the signal ground.

[0008] Furthermore, the second control signal is provided by the MCU.

[0009] Further, the fast shutdown circuit includes: a transistor Q1, a second resistor R2, a first diode D1, a second capacitor C2 and a fifth resistor R5, the cathode of the first diode D1 and one end of the second resistor R2 are connected to the source of the anti-reverse MOS, the other end of the second resistor R2 is connected to the gate of the anti-reverse MOS tube T2, the anode of the first diode D1 is connected to the emitter of the transistor Q1, the collector of the transistor Q1 is connected to the bootstrap circuit and the gate of the anti-reverse MOS tube T2, one end of the second capacitor C2 is connected to the emitter of the transistor Q1, the other end of the second capacitor C2 is connected to the base of the transistor Q1, one end of the fifth resistor R5 is connected to the base of the transistor Q1, and the other end of the fifth resistor R5 is connected to the signal ground.

[0010] Furthermore, the bootstrap circuit includes: a fourth MOS transistor T4, a fifth MOS transistor T5, a third capacitor C3, a fourth capacitor C4, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5 and a sixth resistor R6.

[0011] The gates of the fourth MOS transistor T4 and the fifth MOS transistor T5 are connected to the first control signal, the drain of the fourth MOS transistor T4 is connected to the drain of the anti-reverse MOS transistor T2 and the anode of the fourth diode D4, the source of the fourth MOS transistor T4 is connected to one end of the third capacitor C3 and the drain of the fifth MOS transistor T5, the source of the fifth MOS transistor T5 is connected to one end of the fourth capacitor C4, the other end of the third capacitor C3 is connected to the cathode of the fourth diode D4 and the anode of the fifth diode D5, the other end of the fourth capacitor C4 is connected to the cathode of the fifth diode D5, the anode of the second diode D2, and the anode of the third diode D3, the cathode of the second diode D2 is connected to one end of the sixth resistor R6, the other end of the sixth resistor R6 is connected to the gate of the anti-reverse MOS transistor T2, and the cathode of the third diode D3 is connected to the gate of the initial end MOS transistor T1.

[0012] Furthermore, the first control signal is generated by the MCU.

[0013] Furthermore, the cathode of the third diode D3 is connected to the gate of the initial-end MOS transistor T1 through a filter circuit.

[0014] Further, the filtering circuit includes a fourth resistor R4 and a first capacitor C1, one end of the fourth resistor R4 is connected to the cathode of the third diode D3, the other end of the fourth resistor R4 is connected to one end of the first capacitor C1 and the gate of the initial end MOS tube T1, and the other end of the first capacitor C1 is connected to the source of the initial end MOS tube T1.

[0015] Further, the other end of the fourth resistor R4 is connected to one end of a transient suppression diode TVS1, and the other end of the transient suppression diode TVS1 is connected to the source of the initial-end MOS transistor T1.

[0016] Furthermore, the initial end MOS tube T1 and the anti-reverse MOS tube T2 are both NMOS tubes.

[0017] Beneficial effects of the utility model: The utility model can realize the anti-reverse connection protection capability of 0~48V low-voltage power supply. The back-to-back mode of dual N MOS tubes can greatly reduce power consumption compared with PMOS and improve the stability of operation during operation. The control circuit of the utility model can reduce static current and effectively provide protection capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of an anti-reverse connection device in the prior art.

[0019] Figure 2 It is a structural frame diagram of the utility model.

[0020] Figure 3It is a circuit structure diagram of the utility model. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. The described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0022] In an embodiment of the present utility model, Figure 2 It is a structural block diagram provided according to the specific structure of a positive electrode reverse protection circuit of the utility model, such as Figure 2 As shown, the utility model includes:

[0023] Initial end MOS tube T1, anti-reverse MOS tube T2, fast shutdown circuit 5, control circuit 3 and bootstrap circuit 4;

[0024] The drain of the initial end MOS tube T1 is connected to the bus voltage, the source of the initial end MOS tube T1 is connected to the source of the anti-reverse MOS, the fast shutdown circuit 5 and the bootstrap circuit 4 are connected to the gate of the anti-reverse MOS tube T2, and the control circuit 3 and the bootstrap circuit 4 are connected to the gate of the initial end MOS tube T1;

[0025] The control circuit 3 is used to control the working state of the initial end MOS tube T1, the bootstrap circuit 4 is used to provide bias voltage to the initial end MOS tube T1 and the anti-reverse MOS tube T2, and the fast shutdown circuit 5 is used to quickly shut down the anti-reverse MOS tube T2 when the bus voltage is a negative voltage.

[0026] The initial end MOS tube T1 and the anti-reverse MOS tube T2 are both NMOS tubes.

[0027] In one embodiment of the present invention, Figure 3As shown, the control circuit 3 includes: a first resistor R1, a third resistor R3, a switch MOS tube T3, a Zener diode ZD1 and a seventh resistor R7, one end of the first resistor R1 is connected to the drain of the initial end MOS tube T1, the other end of the first resistor R1 is connected to the gate of the initial end MOS tube T1, one end of the third resistor R3 is connected to the gate of the initial end MOS tube T1, the other end of the third resistor R3 is connected to the drain of the switch MOS tube T3 and the cathode of the Zener diode ZD1, the anode of the Zener diode ZD1 and the source of the switch MOS tube T3 are connected to the signal ground, one end of the seventh resistor R7 is connected to the second control signal and the gate of the switch MOS tube T3, and the other end of the seventh resistor R7 is connected to the signal ground.

[0028] The second control signal is provided by the MCU. Specifically, when the MCU detects that the bus voltage is powered off, it sends the second control signal to turn on the switch MOS tube T3, so that R1 and R3 are grounded to quickly consume the bus voltage.

[0029] In one embodiment of the present invention, Figure 3 As shown, the fast shutdown circuit 5 includes: a transistor Q1, a second resistor R2, a first diode D1, a second capacitor C2 and a fifth resistor R5, the cathode of the first diode D1 and one end of the second resistor R2 are connected to the source of the anti-reverse MOS, the other end of the second resistor R2 is connected to the gate of the anti-reverse MOS tube T2, the anode of the first diode D1 is connected to the emitter of the transistor Q1, the collector of the transistor Q1 is connected to the bootstrap circuit 4 and the gate of the anti-reverse MOS tube T2, one end of the second capacitor C2 is connected to the emitter of the transistor Q1, the other end of the second capacitor C2 is connected to the base of the transistor Q1, one end of the fifth resistor R5 is connected to the base of the transistor Q1, and the other end of the fifth resistor R5 is connected to the signal ground.

[0030] When the connection is reversed, the voltage from the fifth resistor R5 controls the transistor Q1 to open, and then directly turns off the anti-reverse MOS tube T2 to realize the function of protecting the circuit.

[0031] In one embodiment of the present invention, Figure 3 As shown, the bootstrap circuit 4 includes: a fourth MOS transistor T4, a fifth MOS transistor T5, a third capacitor C3, a fourth capacitor C4, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5 and a sixth resistor R6.

[0032] The gates of the fourth MOS transistor T4 and the fifth MOS transistor T5 are connected to the first control signal, the drain of the fourth MOS transistor T4 is connected to the drain of the anti-reverse MOS transistor T2 and the anode of the fourth diode D4, the source of the fourth MOS transistor T4 is connected to one end of the third capacitor C3 and the drain of the fifth MOS transistor T5, the source of the fifth MOS transistor T5 is connected to one end of the fourth capacitor C4, the other end of the third capacitor C3 is connected to the cathode of the fourth diode D4 and the anode of the fifth diode D5, the other end of the fourth capacitor C4 is connected to the cathode of the fifth diode D5, the anode of the second diode D2, and the anode of the third diode D3, the cathode of the second diode D2 is connected to one end of the sixth resistor R6, the other end of the sixth resistor R6 is connected to the gate of the anti-reverse MOS transistor T2, and the cathode of the third diode D3 is connected to the gate of the initial end MOS transistor T1.

[0033] Specifically, the first control signal is generated by the MCU, and the MCU generates the first control signal to control the bootstrap circuit to start.

[0034] Specifically, the cathode of the third diode D3 is connected to the gate of the initial-end MOS transistor T1 through a filter circuit. The filter circuit includes a fourth resistor R4 and a first capacitor C1, one end of the fourth resistor R4 is connected to the cathode of the third diode D3, the other end of the fourth resistor R4 is connected to one end of the first capacitor C1 and the gate of the initial-end MOS transistor T1, and the other end of the first capacitor C1 is connected to the source of the initial-end MOS transistor T1.

[0035] Furthermore, the other end of the fourth resistor R4 is connected to one end of a transient suppression diode TVS1, and the other end of the transient suppression diode TVS1 is connected to the source of the initial end MOS tube T1, wherein the transient suppression diode TVS1 is used to protect electrical components when the voltage overshoots.

[0036] Working mode of the utility model:

[0037] During normal operation, the positive power supply is divided from the first resistor R1 and the second resistor R2 to start the initial end MOS tube T1. After the initial end MOS tube T1 is turned on, the bootstrap circuit is powered through the body diode of the anti-reverse MOS tube T2. At this time, the MCU generates a first control signal to start the bootstrap circuit.

[0038] When the MCU detects power failure, it generates a second control signal to enable the switch MOS tube T3, so that R1 and R3 are grounded to quickly consume the bus voltage. At this time, the initial end MOS tube T1 and the anti-reverse MOS tube T2 are turned off to achieve the purpose of quickly powering off the system to protect the back-end low-voltage chip.

[0039] Value selection:

[0040] The ratio of the first resistor R1 to the third resistor R3 is about 50:1. The third resistor R3 is 4.7K at 12V, 10K at 24V, and 20K at 48V, mainly to ensure that the working current of the Zener diode ZD1 is about 5mA during normal operation. The main function of the Zener diode ZD1 is to protect the switch MOS tube T3 from being damaged, so a voltage value of 36V is selected.

[0041] Reverse polarity operation:

[0042] When the connection is reversed, the voltage from the fifth resistor R5 controls the transistor Q1 to open, and then directly turns off the anti-reverse MOS tube T2 to realize the function of protecting the circuit.

[0043] Value selection:

[0044] The fifth resistor R5 is a 10K current limiting resistor to prevent the transistor Q1 from being damaged when the power supply is reversely connected.

[0045] Transistor Q1 needs to have a Vge greater than 48V, and 60V is generally selected here.

[0046] The second capacitor C2 affects the RC time of closing the transistor Q1, and generally a capacitor of nF level is selected.

[0047] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to examples, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A positive electrode reverse protection circuit, characterized in that: include: An initial end MOS tube T1, an anti-reverse MOS tube T2, a fast shutdown circuit (5), a control circuit (3) and a bootstrap circuit (4); The drain of the initial end MOS tube T1 is connected to the bus voltage, the source of the initial end MOS tube T1 is connected to the source of the anti-reverse MOS, the fast shutdown circuit (5) and the bootstrap circuit (4) are connected to the gate of the anti-reverse MOS tube T2, and the control circuit (3) and the bootstrap circuit (4) are connected to the gate of the initial end MOS tube T1; The control circuit (3) is used to control the working state of the initial end MOS tube T1, the bootstrap circuit (4) is used to provide a bias voltage to the initial end MOS tube T1 and the anti-reverse MOS tube T2, and the fast shutdown circuit (5) is used to quickly shut down the anti-reverse MOS tube T2 when the bus voltage is a negative voltage.

2. The positive electrode reverse protection circuit according to claim 1, characterized in that: The control circuit (3) comprises: a first resistor R1, a third resistor R3, a switch MOS tube T3, a Zener diode ZD1 and a seventh resistor R7, one end of the first resistor R1 is connected to the drain of the initial MOS tube T1, the other end of the first resistor R1 is connected to the gate of the initial MOS tube T1, one end of the third resistor R3 is connected to the gate of the initial MOS tube T1, the other end of the third resistor R3 is connected to the drain of the switch MOS tube T3 and the cathode of the Zener diode ZD1, the anode of the Zener diode ZD1 and the source of the switch MOS tube T3 are connected to the signal ground, one end of the seventh resistor R7 is connected to the second control signal and the gate of the switch MOS tube T3, and the other end of the seventh resistor R7 is connected to the signal ground.

3. The positive electrode reverse protection circuit according to claim 2, characterized in that: The second control signal is provided by the MCU.

4. The positive electrode reverse protection circuit according to claim 1, characterized in that: The fast shutdown circuit (5) comprises: a transistor Q1, a second resistor R2, a first diode D1, a second capacitor C2 and a fifth resistor R5, wherein the cathode of the first diode D1 and one end of the second resistor R2 are connected to the source of the anti-reverse MOS, the other end of the second resistor R2 is connected to the gate of the anti-reverse MOS tube T2, the anode of the first diode D1 is connected to the emitter of the transistor Q1, the collector of the transistor Q1 is connected to the bootstrap circuit (4) and the gate of the anti-reverse MOS tube T2, one end of the second capacitor C2 is connected to the emitter of the transistor Q1, the other end of the second capacitor C2 is connected to the base of the transistor Q1, one end of the fifth resistor R5 is connected to the base of the transistor Q1, and the other end of the fifth resistor R5 is connected to the signal ground.

5. The positive electrode reverse protection circuit according to claim 1, characterized in that: The bootstrap circuit (4) comprises: a fourth MOS transistor T4, a fifth MOS transistor T5, a third capacitor C3, a fourth capacitor C4, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5 and a sixth resistor R6, The gates of the fourth MOS transistor T4 and the fifth MOS transistor T5 are connected to the first control signal, the drain of the fourth MOS transistor T4 is connected to the drain of the anti-reverse MOS transistor T2 and the anode of the fourth diode D4, the source of the fourth MOS transistor T4 is connected to one end of the third capacitor C3 and the drain of the fifth MOS transistor T5, the source of the fifth MOS transistor T5 is connected to one end of the fourth capacitor C4, the other end of the third capacitor C3 is connected to the cathode of the fourth diode D4 and the anode of the fifth diode D5, the other end of the fourth capacitor C4 is connected to the cathode of the fifth diode D5, the anode of the second diode D2, and the anode of the third diode D3, the cathode of the second diode D2 is connected to one end of the sixth resistor R6, the other end of the sixth resistor R6 is connected to the gate of the anti-reverse MOS transistor T2, and the cathode of the third diode D3 is connected to the gate of the initial end MOS transistor T1.

6. The positive electrode reverse protection circuit according to claim 5, characterized in that: The first control signal is generated by the MCU.

7. The positive electrode reverse protection circuit according to claim 5, characterized in that: The cathode of the third diode D3 is connected to the gate of the initial-end MOS transistor T1 through a filter circuit.

8. The positive electrode reverse protection circuit according to claim 7, characterized in that: The filter circuit includes a fourth resistor R4 and a first capacitor C1, one end of the fourth resistor R4 is connected to the cathode of the third diode D3, the other end of the fourth resistor R4 is connected to one end of the first capacitor C1 and the gate of the initial end MOS tube T1, and the other end of the first capacitor C1 is connected to the source of the initial end MOS tube T1.

9. The positive electrode reverse protection circuit according to claim 8, characterized in that: The other end of the fourth resistor R4 is connected to one end of the transient suppression diode TVS1, and the other end of the transient suppression diode TVS1 is connected to the source of the initial-end MOS transistor T1.

10. The positive electrode reverse protection circuit according to claim 1, characterized in that: The initial end MOS tube T1 and the anti-reverse MOS tube T2 are both NMOS tubes.

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