Reverse connection prevention circuit with filtering function

Abstract

The utility model discloses an anti-reverse-connection circuit with a filtering function. The anti-reverse-connection circuit comprises a common-mode filtering unit, an anti-reverse-connection unit and a differential-mode filtering unit. The common-mode filtering unit comprises a transient suppression diode TVS1, a capacitor C1, a capacitor C2, a common-mode inductor L1, a capacitor C3 and a capacitor C4; the reverse connection prevention unit comprises a PMOS transistor Q1, a resistor R1, a resistor R2 and a voltage stabilizing diode D1. The differential mode filtering unit comprises a capacitor C5, an inductor L2 and a capacitor C6; according to the utility model, the conduction voltage drop of the airborne ECU host of the intelligent automobile can be reduced, so that the energy consumption of the circuit is reduced, and the stability of the circuit is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of automobile, especially a kind of anti-reverse connection circuit with filtering function. BACKGROUND

[0002] With the popularization and technical development of intelligent automobile, the power consumption of vehicle-mounted ECU host on intelligent automobile is higher and higher, and in practice, it is required that vehicle-mounted ECU host has anti-reverse connection and high stability. In the prior art, diode is mainly used to realize anti-reverse connection function. However, diode generally has voltage drop, even if Schottky diode is used, there is still about 0.5V voltage drop and causes diode to heat, so that the power consumption of circuit is high. At the same time, the voltage drop fluctuates with the change of current, which causes poor circuit stability. Therefore, how to develop a new structure of anti-reverse connection circuit to overcome the above problems in the prior art is a direction that needs to be further studied by the person skilled in the art. SUMMARY

[0003] The utility model aims at providing an anti-reverse connection circuit with filtering function, which can reduce the on-voltage drop of vehicle-mounted ECU host, thereby reducing the power consumption of circuit and improving the stability of circuit.

[0004] The utility model discloses an anti-reverse connection circuit with filtering function, which comprises:

[0005] A common-mode filter unit comprises a transient voltage suppression diode TVS1, a capacitor C1, a capacitor C2, a common-mode inductor L1, a capacitor C3 and a capacitor C4. The two ends of the transient voltage suppression diode TVS1 are respectively connected to the positive and negative electrodes of an input voltage. The two ends of the capacitor C1 are respectively connected to the two ends of the transient voltage suppression diode TVS1. One end of the capacitor C2 is connected to one end of the capacitor C1, and the other end of the capacitor C2 is connected to the other end of the capacitor C1 and grounded. The first end of the common-mode inductor L1 is connected to one end of the capacitor C2. The second end of the common-mode inductor L1 is connected to the other end of the capacitor C2. The third end of the common-mode inductor L1 is connected to one end of the capacitor C3. The fourth end of the common-mode inductor L1 is connected to the other end of the capacitor C3 and grounded. One end of the capacitor C4 is connected to one end of the capacitor C3, and the other end of the capacitor C4 is connected to the other end of the capacitor C3.

[0006] An anti-reverse connection unit comprises a PMOS transistor Q1, a resistor R1, a resistor R2 and a zener diode D1. The drain of the PMOS transistor Q1 is connected to one end of the capacitor C4. The source of the PMOS transistor Q1 is connected to one end of the resistor R1 and the negative electrode of the zener diode D1. The gate of the PMOS transistor Q1 is connected to the other end of the resistor R1, the positive electrode of the zener diode D1 and one end of the resistor R2. The other end of the resistor R2 is connected to the other end of the capacitor C4.

[0007] The differential mode filter unit comprises a capacitor C5, an inductor L2 and a capacitor C6; one end of the capacitor C5 is connected with a negative electrode of a voltage stabilizing diode D1 and one end of the inductor L2; the other end of the inductor L2 is connected with one end of the capacitor C6 and an output port Vout; the other end of the capacitor C5 is connected with the other end of the resistor R2 and the other end of the capacitor C6.

[0008] Preferably, the capacitor value of the capacitor C1 is 4.7uF; the capacitor value of the capacitor C2 is 0.1uF; the capacitor value of the capacitor C3 is 0.1uF and the capacitor value of the capacitor C4 is 4.7uF.

[0009] Preferably, the transient voltage suppression diode TVS1 adopts SM6A30CA.

[0010] Preferably, the resistance value of the resistor R1 is 470KΩ, the resistance value of the resistor R2 is 240KΩ; the PMOS tube Q1 adopts DMP6023LSS-13; the voltage stabilizing diode D1 adopts MMSZ5245B.

[0011] Preferably, the capacitor value of the capacitor C5 is 220uF.

[0012] The inductor L2 adopts SMTDRH105R-100N.

[0013] Compared with the prior art, the utility model has the following advantages:

[0014] Firstly, the utility model greatly reduces the turn-on voltage drop problem, so the turn-on voltage drop fluctuation is small, the output voltage is stable, and the circuit reliability is higher.

[0015] Secondly, the utility model has low forward conduction power consumption and low heat generation, and is more energy-saving.

[0016] Thirdly, the utility model has simple structure and is easy to prepare, can realize the anti-reverse connection function and the filtering function at the same time, and meets the related requirements of the intelligent vehicle-mounted system. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a circuit structure schematic view of the embodiment 1. DETAILED DESCRIPTION

[0018] The embodiments of the present application will be described in detail with specific examples. The skilled in the art can easily understand other advantages and effects of the present application from the disclosure. The present application can also be implemented or applied in other different embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the present application.

[0019] Embodiment 1, please refer to Figure 1 :

[0020] A reverse connection prevention circuit with filtering function comprises a common mode filter unit, a reverse connection prevention unit and a differential mode filter unit.

[0021] The common mode filter unit comprises a transient voltage suppression diode TVS1, a capacitor C1, a capacitor C2, a common mode inductor L1, a capacitor C3 and a capacitor C4; the reverse connection prevention unit comprises a PMOS transistor Q1, a resistor R1, a resistor R2 and a voltage stabilizing diode D1; and the differential mode filter unit comprises a capacitor C5, an inductor L2 and a capacitor C6.

[0022] The first end of the transient voltage suppression diode TVS1 is connected to the positive pole of an input voltage, and the second end of the transient voltage suppression diode TVS1 is connected to the negative pole of the input voltage; the first end of the capacitor C1 is connected to the first end of the transient voltage suppression diode TVS1, and the second end of the capacitor C1 is connected to the second end of the transient voltage suppression diode TVS1; the first end of the capacitor C2 is connected to the first end of the capacitor C1, and the second end of the capacitor C2 is connected to the second end of the capacitor C1 and grounded; the first end of the common mode inductor L1 is connected to the first end of the capacitor C2; the second end of the common mode inductor L1 is connected to the second end of the capacitor C2; the first end of the capacitor C3 is connected to the third end of the common mode inductor L1; the second end of the capacitor C3 is connected to the fourth end of the common mode inductor L1 and grounded; the first end of the capacitor C4 is connected to the first end of the capacitor C3, and the second end of the capacitor C4 is connected to the second end of the capacitor C3.

[0023] The drain of the PMOS transistor Q1 is connected to the first end of the capacitor C4; the source of the PMOS transistor Q1 is connected to the first end of the resistor R1 and the negative pole of the voltage stabilizing diode D1 respectively; the gate of the PMOS transistor Q1 is connected to the second end of the resistor R1, the positive pole of the voltage stabilizing diode D1 and the first end of the resistor R2 respectively; and the second end of the resistor R2 is connected to the second end of the capacitor C4.

[0024] The first end of the capacitor C5 is connected with the negative pole of the voltage stabilizing diode D1 and the first end of the inductor L2 respectively; the second end of the inductor L2 is connected with the first end of the capacitor C6 and the output port Vout respectively; the second end of the capacitor C5 is connected with the second end of the resistor R2 and the second end of the capacitor C6 respectively.

[0025] In the example, the capacitance of the capacitor C1 is 4.7uF; the capacitance of the capacitor C2 is 0.1uF; the capacitance of the capacitor C3 is 0.1uF, and the capacitance of the capacitor C4 is 4.7uF. The transient suppression diode TVS1 adopts SM6A30CA. The resistance of the resistor R1 is 470KΩ, and the resistance of the resistor R2 is 240KΩ; the PMOS tube Q1 adopts DMP6023LSS-13; the voltage stabilizing diode D1 adopts MMSZ5245B. The capacitance of the capacitor C5 is 220uF; the inductor L2 adopts SMTDRH105R-100N.

[0026] In practice, the working process is as follows:

[0027] The input voltage is first output to the transient suppression diode TVS1, absorbs the surge through the transient suppression diode TVS1, and then enters the common mode inductor after being filtered by the capacitor C1 and the capacitor C2. The common mode inductor can well suppress the common mode interference signal in the input voltage, and then the input voltage is sent to the anti-reverse connection unit through the capacitor C3 and the capacitor C4: first to the drain of the PMOS tube Q1, because the body diode of the PMOS tube Q1, the input voltage is directly conducted to the source, and is divided by the resistor R1 and the resistor R2 to the gate of the PMOS tube Q1, at this time the source voltage is higher than the gate voltage, the PMOS tube Q1 is turned on, and then the input voltage is conducted to the differential mode filter unit, and is sent to the later stage power supply after being stabilized by the pi type filter composed of the capacitor C5, the inductor L2 and the capacitor C6.

[0028] In the above process, the pressure difference generated by the input voltage is only generated by the resistance between the drain and the source after the PMOS tube Q1 is turned on. In this example, since the PMOS tube Q1 adopts DMP6023LSS-13, its on-resistance is 33mΩ, and when the working current is 2A, the voltage drop generated is 0.066V, which is much lower than the 0.5V voltage drop of the Schottky diode in the prior art. The resistors R1 and R2 form a suitable voltage dividing resistor, which can ensure that the normal input voltage will not damage the PMOS tube Q1. Considering that there may be surges, the scheme further protects the PMOS tube Q1 by setting the voltage stabilizing diode D1: when the circuit is reversed, at this time the input voltage passes through the resistor R2 into the voltage stabilizing diode D1, the voltage stabilizing diode D1 is turned on, and the voltage is clamped at the tube voltage drop 0.9V, at this time the gate voltage of the PMOS tube Q1 is higher than the source voltage, the PMOS tube Q1 is closed, and the body diode of the PMOS is in the reverse connection state and does not conduct, thereby realizing the anti-reverse connection function.

[0029] The embodiments of the utility model are described in detail above in combination with the drawings, but the utility model is not limited to the above-mentioned embodiments. Even if various changes are made to the utility model, if the changes belong to the scope of the claims of the utility model and equivalent technologies, they still fall within the protection scope of the utility model.

Claims

1. A reverse connection protection circuit with filtering function, characterized in that, Comprises: Common mode filter unit, the common mode filter unit includes: transient voltage suppression diode TVS1, capacitor C1, capacitor C2, common mode inductance L1, capacitor C3, capacitor C4;The two ends of the transient voltage suppression diode TVS1 are connected with the positive and negative poles of input voltage respectively;The two ends of the capacitor C1 are connected with the two ends of the transient voltage suppression diode TVS1 respectively;One end of the capacitor C2 is connected with one end of the capacitor C1, and the other end of the capacitor C2 is connected with the other end of the capacitor C1 and grounded;The first end of the common mode inductance L1 is connected with one end of the capacitor C2;The second end of the common mode inductance L1 is connected with the other end of the capacitor C2;The third end of the common mode inductance L1 is connected with one end of the capacitor C3;The fourth end of the common mode inductance L1 is connected with the other end of the capacitor C3 and grounded;One end of the capacitor C4 is connected with one end of the capacitor C3, and the other end of the capacitor C4 is connected with the other end of the capacitor C3; Reverse connection prevention unit, the reverse connection prevention unit includes PMOS tube Q1, resistance R1, resistance R2, voltage stabilizing diode D1;The drain of the PMOS tube Q1 is connected with one end of the capacitor C4;The source of the PMOS tube Q1 is connected with one end of the resistance R1 and the negative pole of the voltage stabilizing diode D1;The gate of the PMOS tube Q1 is connected with the other end of the resistance R1, the positive pole of the voltage stabilizing diode D1 and one end of the resistance R2;The other end of the resistance R2 is connected with the other end of the capacitor C4; Differential mode filter unit, the differential mode filter unit includes capacitor C5, inductance L2, capacitor C6;One end of the capacitor C5 is connected with the negative pole of the voltage stabilizing diode D1 and one end of the inductance L2;The other end of the inductance L2 is connected with one end of the capacitor C6 and output port Vout;The other end of the capacitor C5 is connected with the other end of the resistance R2 and the other end of the capacitor C6. 2.The reverse connection prevention circuit with filtering function according to claim 1, wherein the capacitance of the capacitor C1 is 4.7uF;The capacitance of the capacitor C2 is 0.1uF;The capacitance of the capacitor C3 is 0.1uF, and the capacitance of the capacitor C4 is 4.7uF. 3.The reverse connection prevention circuit with filtering function according to claim 2, wherein the transient voltage suppression diode TVS1 adopts SM6A30CA. 4.The reverse connection prevention circuit with filtering function according to claim 3, wherein the resistance of the resistance R1 is 470KΩ, and the resistance of the resistance R2 is 240KΩ;The PMOS tube Q1 adopts DMP6023LSS-13;The voltage stabilizing diode D1 adopts MMSZ5245B. 5.The reverse connection prevention circuit with filtering function according to claim 4, wherein the capacitance of the capacitor C5 is 220uF;The inductance L2 adopts SMTDRH105R-100N. ​ ​ ​ ​

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