CN211930922U - Automobile driving front end PMOS anti-backflow circuit - Google Patents
Automobile driving front end PMOS anti-backflow circuit Download PDFInfo
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- CN211930922U CN211930922U CN202020791443.8U CN202020791443U CN211930922U CN 211930922 U CN211930922 U CN 211930922U CN 202020791443 U CN202020791443 U CN 202020791443U CN 211930922 U CN211930922 U CN 211930922U
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Abstract
The utility model discloses a backward flow preventing circuit for PMOS (P-channel metal oxide semiconductor) at the front end of an automobile drive, which comprises a first backward flow preventing circuit, a second backward flow preventing circuit, a third backward flow preventing circuit, a backward flow preventing control circuit, a DCDC (direct current-direct current) drive circuit and an MCU (micro control unit); the power supply TI is connected with the input end of the first anti-reverse circuit, and the output end of the first anti-reverse circuit is connected with the power supply input end of the DCDC drive circuit; the power supply PL is connected with the input end of a second anti-reverse circuit, and the output end of the second anti-reverse circuit is connected with the power supply input end of the DCDC drive circuit; the power supply DRL is connected with the input end of a third anti-reflection circuit, and the output end of the third anti-reflection circuit is connected with the power supply input end of the DCDC drive circuit; prevent flowing backward control circuit one end and third anti-reflection circuit input and be connected, one end and third anti-reflection circuit output are connected, and the other end is connected with third anti-reflection circuit control end. The utility model discloses a prevent flowing backward control circuit and gather the input of third prevention anti-circuit and the voltage of output and control the opening and the closing of NPN triode to PMOS's opening and closing in the control third prevention anti-circuit.
Description
Technical Field
The utility model relates to an automobile-used LED light control technology, concretely relates to car light drive front end prevents flowing backward control circuit of preventing of anti-PMOS.
Background
The applications of the high and low beam, the daytime running position lamp, the steering lamp and the auxiliary daytime running lamp in the automobile lamp are very common, and because the automobile lamp tends to be miniaturized and cost is considered, the driving control circuit of each function is also developed from single-function driving to integral driving. In the integrated driving circuit, according to different powers, the front end of the power input with multiple functions is prevented from reversely relating to a Schottky diode and a PMOS, the PMOS is required to be used for preventing reverse connection of high power, the problem of PMOS reverse flow is solved, the important effect of optimizing the space and the cost of the whole control circuit is played, and the problem is urgently required to be solved in actual design and manufacturing work.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing an automobile drive front end PMOS prevents flowing backward circuit to above-mentioned problem, its adopt prevent flowing backward control circuit gather the input of third prevention anti-circuit and the voltage of output control NPN triode open and close to control the opening and closing of PMOS in the third prevention anti-circuit.
The utility model provides a car drive front end PMOS prevents flowing backward circuit, includes that the first prevents the anti-circuit that prevents, the second prevents the anti-circuit that prevents, the anti-circuit of third prevents flowing backward control circuit, DCDC drive circuit and MCU, characterized by:
the first anti-reverse circuit is provided with an input end and an output end;
the input end of the first anti-reverse circuit is connected with a power supply TI, and the output end of the first anti-reverse circuit is connected with the power supply input end of the DCDC drive circuit;
the second anti-reverse circuit is provided with an input end and an output end;
the input end of the second anti-reverse circuit is connected with a power supply PL, and the output end of the second anti-reverse circuit is connected with the power supply input end of the DCDC drive circuit;
the third anti-reflection circuit is provided with an input end, an output end and a control end;
the input end of the third anti-backflow circuit is connected with one end of the power supply DRL and one end of the anti-backflow circuit, the output end of the third anti-backflow circuit is connected with the power supply input end of the DCDC drive circuit and one end of the anti-backflow circuit, and the control end of the third anti-backflow circuit is connected with the other end of the anti-backflow control circuit;
the MCU is provided with three I/O ports which are respectively connected with power supplies TI, PL and DRL;
specifically, the first anti-reverse circuit is a schottky diode.
Further, the second anti-reverse circuit is a schottky diode.
Furthermore, in the third anti-backflow circuit, a drain electrode of the PMOS is connected with the power supply DRL, a source electrode of the PMOS is connected with one end of the fourth resistor, a negative electrode of the zener diode and a power supply input end of the DCDC driving circuit, and a gate electrode of the PMOS is connected with one end of the fourth resistor and a positive electrode of the zener diode and is connected with a collector electrode of an NPN triode in the anti-backflow circuit through the fifth resistor;
in the anti-backflow control circuit, one end of a first resistor is connected with a drain electrode of a PMOS (P-channel metal oxide semiconductor), the other end of the first resistor is connected with one end of a second resistor and a positive electrode of a comparator, the other end of the second resistor is connected with the ground, one end of an eighth resistor is connected with a source electrode of the PMOS, the other end of the eighth resistor is connected with one end of a third resistor and a negative electrode of the comparator, the other end of the third resistor is connected with the ground, an output end of the comparator is connected with one end of a seventh resistor and a base electrode of an NPN (negative-positive-negative) triode through a sixth resistor, the other end of the seventh resistor is grounded, a collector of the NPN triode is connected with one end of the fifth resistor;
further, the MCU has a function of sampling the power signals TI, PL and TURN.
Compared with the prior art, the utility model has the advantages that:
1. under the condition that the power supply PL and the DRL supply power to the DCDC drive circuit together through two anti-reverse circuits or the power supply TI, the power supply PL and the DRL supply power to the DCDC drive circuit together through three anti-reverse circuits, when the DRL power supply is removed, the PL and TI power supply is prevented from reversely flowing to the DRL end through the anti-reverse control circuit, and therefore the MCU is prevented from mistakenly sampling DRL power supply signals.
2. The whole circuit is simple in structure, high in reliability and low in implementation cost.
Drawings
Fig. 1 is a schematic structural diagram of the present invention.
Fig. 2 is a circuit diagram of an embodiment of the present invention.
Detailed Description
The present invention will be further explained with reference to the drawings and examples.
In fig. 1, the technical problem to be solved by the present invention is to provide a backward flow preventing circuit for front PMOS of a vehicle driver. The backflow prevention control circuit is used for collecting the voltage of the input end and the voltage of the output end of the third anti-reflection circuit to control the on and off of the NPN triode, so that the on and off of a PMOS in the third anti-reflection circuit are controlled;
the technical scheme of the utility model is that: the utility model provides a car drive front end PMOS prevents flowing backward circuit, prevent flowing backward circuit including first, the second prevents the circuit of flowing backward, and the third prevents the circuit of flowing backward, prevents flowing backward control circuit, DCDC drive circuit and MCU, its novel point of using lies in:
the first anti-reverse circuit is provided with an input end a and an output end b;
the input end a of the first anti-reverse circuit is connected with a power supply TI, and the output end b of the first anti-reverse circuit is connected with the power supply input end of the DCDC drive circuit;
the second anti-reverse circuit is provided with an input end c and an output end d;
the input end c of the second anti-reverse circuit is connected with a power supply PL, and the output end d of the second anti-reverse circuit is connected with the power supply input end of the DCDC drive circuit;
the third anti-reflection circuit is provided with an input end e, an output end f and a control end g;
the input end e of the third anti-backflow circuit is connected with the power supply DRL and one end h of the anti-backflow circuit, the output end f of the third anti-backflow circuit is connected with the power supply input end k of the DCDC drive circuit and one end j of the anti-backflow circuit, and the control end g of the third anti-backflow circuit is connected with the other end i of the anti-backflow control circuit;
the MCU is provided with three I/O ports M, N and O which are respectively connected with power supplies TI, PL and DRL;
in fig. 2, under the condition that the power supplies PL and DRL supply power to the DCDC driving circuit through two anti-inversion circuits or the power supplies TI, PL and DRL supply power to the DCDC driving circuit through three anti-inversion circuits, when the DRL power supply is removed, the anti-inversion control circuit collects the voltages of the input and output ends of the third anti-inversion circuit to control the on and off of the NPN triode, thereby controlling the on and off of the PMOS in the third anti-inversion circuit to prevent the PL and TI power supplies from flowing backwards to the DRL end, and thereby preventing the MCU from mis-sampling the DRL power supply signal;
according to the technical scheme, a first anti-reverse circuit, a second anti-reverse circuit, a third anti-reverse circuit, an anti-reverse control circuit, a DCDC drive circuit and an MCU are arranged;
the input end a of the first anti-reverse circuit is connected with a power supply TI, and the output end b of the first anti-reverse circuit is connected with the power supply input end of the DCDC drive circuit;
the first anti-reverse circuit is a Schottky diode D1.
The input end c of the second anti-reverse circuit is connected with a power supply PL, and the output end d of the second anti-reverse circuit is connected with the power supply input end of the DCDC drive circuit;
the second anti-reverse circuit is a Schottky diode D2.
The input end e of the third anti-backflow circuit is connected with the power supply DRL and one end h of the anti-backflow circuit, the output end f of the third anti-backflow circuit is connected with the power supply input end k of the DCDC drive circuit and one end j of the anti-backflow circuit, and the control end g of the third anti-backflow circuit is connected with the other end i of the anti-backflow control circuit;
in the third anti-backflow circuit, the drain of a PMOS transistor Q1 is connected with a power supply DRL, the source of a PMOS transistor Q1 is connected with one end of a fourth resistor R4, the cathode of a zener diode D3 and the power supply input end of a DCDC drive circuit, the gate of a PMOS transistor Q1 is connected with one end of a fourth resistor R4 and the anode of a zener diode D3, and is connected with the collector of an NPN triode Q2 in the anti-backflow circuit through a fifth resistor R5;
in the anti-backflow control circuit, one end of a first resistor R1 is connected with the drain of a PMOS tube Q1, the other end of the first resistor R1 is connected with one end of a second resistor R2 and the anode of a comparator U1, the other end of the second resistor R2 is connected with the ground, one end of an eighth resistor R8 is connected with the source of the PMOS tube Q1, the other end of the eighth resistor R8 is connected with one end of a third resistor R3 and the cathode of the comparator U1, the other end of the third resistor R3 is connected with the ground, the output end of the comparator U1 is connected with one end of a seventh resistor R7 and the base of an NPN Q2 through a sixth resistor R6, the other end of the seventh resistor R7 is grounded, the collector of the NPN triode Q2 is connected with one end of a fifth resistor R5, and the emitter of an NPN triode Q2 is grounded;
the MCU is provided with three I/O ports M, N and O which are respectively connected with power supplies TI, PL and DRL;
the specific working principle is as follows:
under the condition that the power supplies PL and DRL supply power to the DCDC drive circuit through two anti-reverse circuits or the power supplies TI, PL and DRL supply power to the DCDC drive circuit through three anti-reverse circuits, the positive and negative input ends of a comparator U1(LM2904AVQDRQ1) in the anti-backflow circuit acquire the voltage values of the input end e and the output end f of the third anti-backflow circuit through the voltage division values of resistors R1 and R2 and resistors R8 and R3 (wherein R1 is R8-10K, and R2 is R3-2K), because the third anti-reflection circuit generates voltage drop through forward conduction of the MOS parasitic diode, the voltage of the input end e of the third anti-reflection circuit is higher than the voltage of the output end f, the voltage of the positive input end of the comparator U1 is higher than the voltage of the negative input end, the output of the comparator U1 is high, the transistor Q2(BC817Q) is turned on by voltage dividing resistors R6 and R7 (where R6 is 10K and R7 is 2K), so that the voltage V at f end of the MOS in the third inversion circuit is obtained.fV is formed by voltage dividing resistors R4 and R5(R4 ═ R5 ═ 10K)SG＞VthAt the moment, the PMOS is conducted, the conduction voltage drop of the third anti-reflection circuit is smaller than the conduction voltage drops of the first anti-reflection circuit and the second anti-reflection circuit, and all power supplies TI, PL and DRL supply power to the DCDC driving circuit through the respective anti-reflection circuits.
Under the condition that the power supply PL and the DRL supply power to the DCDC drive circuit together through two anti-reverse circuits or the power supply TI, the power supply PL and the DRL supply power to the DCDC drive circuit together through three anti-reverse circuits, when the DRL power supply is removed, the third anti-reverse circuit is conducted reversely instantly, as the voltage drop is generated by the reverse conduction of the third anti-reverse circuit through the MOS conduction resistor, the voltage of the input end e of the third anti-reverse circuit is lower than the voltage of the output end f, and the voltage of the positive input end of the comparator U1 is lower than the voltage of the negative input endThe output of the comparator U1 is low, and the transistor Q2(BC817Q) is turned off by the voltage dividing resistors R6 and R7 (where R6 is 10K and R7 is 2K), so that the MOS V in the third anti-glitch circuit is VSG<VthAt this time, the PMOS is closed, and PL and TI power supplies cannot reversely flow to the DRL end, so that the MCU is prevented from sampling the DRL power supply signal by mistake.
The utility model aims to solve the technical problem that a circuit is prevented flowing backward by car drive front end PMOS is provided. Under the condition that the power supply PL and the DRL supply power to the DCDC drive circuit together through two anti-reverse circuits or the power supply TI and the power supply DRL supply power to the DCDC drive circuit together through three anti-reverse circuits, when the DRL power supply is removed, the reverse flow prevention control circuit collects the voltage of the input end and the output end of the third anti-reverse circuit to control the on and off of the NPN triode, so that the on and off of the PMOS in the third anti-reverse circuit are controlled, the PL and TI power supply are prevented from reversely flowing to the DRL end, and the MCU is prevented from mistakenly sampling the DRL power supply signal.
Claims (6)
1. A PMOS anti-backflow circuit at the front end of an automobile drive is characterized by comprising a first anti-backflow circuit, a second anti-backflow circuit, a third anti-backflow circuit, an anti-backflow control circuit, a DCDC drive circuit and an MCU, wherein the first anti-backflow circuit is provided with an input end and an output end;
the input end of the first anti-reverse circuit is connected with a power supply TI, and the output end of the first anti-reverse circuit is connected with the power supply input end of the DCDC drive circuit;
the second anti-reverse circuit is provided with an input end and an output end;
the input end of the second anti-reverse circuit is connected with a power supply PL, and the output end of the second anti-reverse circuit is connected with the power supply input end of the DCDC drive circuit;
the third anti-reflection circuit is provided with an input end, an output end and a control end;
the input end of the third anti-backflow circuit is connected with one end of the power supply DRL and one end of the anti-backflow circuit, the output end of the third anti-backflow circuit is connected with the power supply input end of the DCDC drive circuit and one end of the anti-backflow circuit, and the control end of the third anti-backflow circuit is connected with the other end of the anti-backflow control circuit;
the MCU is provided with three I/O ports which are respectively connected with power supplies TI, PL and DRL.
2. The automotive drive front end PMOS anti-back flow circuit according to claim 1, wherein said first anti-back flow circuit is a schottky diode.
3. The automotive drive front end PMOS anti-backup circuit according to claim 1, wherein said second anti-backup circuit is a schottky diode.
4. The automotive driving front end PMOS anti-backflow circuit according to claim 1, wherein in the third anti-backflow circuit, a drain electrode of the PMOS is connected with a DRL (source driver level), a source electrode of the PMOS is connected with one end of a fourth resistor, a negative electrode of a voltage stabilizing diode and a power supply input end of the DCDC driving circuit, and a grid electrode of the PMOS is connected with one end of the fourth resistor and a positive electrode of the voltage stabilizing diode and is connected with an NPN triode collector electrode in the anti-backflow circuit through a fifth resistor.
5. The automotive front end PMOS backflow prevention circuit as claimed in claim 1, wherein in the backflow prevention control circuit, one end of a first resistor is connected to a drain electrode of the PMOS, the other end of the first resistor is connected to one end of a second resistor and a positive electrode of the comparator, the other end of the second resistor is connected to ground, one end of an eighth resistor is connected to a source electrode of the PMOS, the other end of the eighth resistor is connected to one end of a third resistor and a negative electrode of the comparator, the other end of the third resistor is connected to ground, an output end of the comparator is connected to one end of a seventh resistor and a base electrode of the NPN triode through a sixth resistor, the other end of the seventh resistor is grounded, a collector electrode of the NPN triode is connected to one end of the fifth resistor, and an emitter electrode of the NPN triode is grounded.
6. The front-end PMOS anti-back flow circuit of claim 1, wherein said MCU has a function of sampling power signals TI, PL and TURN.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020791443.8U CN211930922U (en) | 2020-05-13 | 2020-05-13 | Automobile driving front end PMOS anti-backflow circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020791443.8U CN211930922U (en) | 2020-05-13 | 2020-05-13 | Automobile driving front end PMOS anti-backflow circuit |
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| Publication Number | Publication Date |
|---|---|
| CN211930922U true CN211930922U (en) | 2020-11-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020791443.8U Active CN211930922U (en) | 2020-05-13 | 2020-05-13 | Automobile driving front end PMOS anti-backflow circuit |
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| Country | Link |
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| CN (1) | CN211930922U (en) |
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- 2020-05-13 CN CN202020791443.8U patent/CN211930922U/en active Active
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