CN210405724U - Contactless large-current MOS tube driving circuit - Google Patents

Abstract

The utility model provides a contactless heavy current MOS manages drive circuit belongs to electronic switch technical field. The method solves the problem of how to realize the quick switching response of the MOS for controlling the large current by the small current. The circuit comprises a single chip microcomputer, an MOS tube Q2, a capacitor C2, a capacitor C3, a resistor R1, a triode Q1, a four-input NAND gate module and a bridge rectifier module, the base of a triode Q1 is connected with an I/O port of the single chip microcomputer, the collector of the triode Q1 is connected with a power supply through the resistor R1, the collector of the triode Q1 is also connected with the input end of the four-input NAND gate module, the emitter of the triode Q1 is grounded, two output ends of the four-input NAND gate module are respectively connected with the bridge rectifier module through the capacitor C2 and the capacitor C3, the output end of the bridge rectifier module is connected with the grid of the MOS tube Q2, and the source of the MOS tube Q2 is. The MOS tube is driven to be opened by controlling a large current with a small current, and the switch response speed is high.

Description

Contactless large-current MOS tube driving circuit

Technical Field

The utility model belongs to the technical field of electronic switch, a contactless heavy current MOS manages drive circuit is related to.

Background

In lighting applications, the light emitting diode LED is considered to be one of the most potential light sources at present because of its characteristics of high luminous efficiency, long life, high brightness, energy saving, environmental protection, durability, and the like. High brightness LEDs require an accurate, high efficiency DC current source, a dimming method, and various protection functions must be provided. In addition, the driver ICs of these LEDs must be designed to meet the above requirements under a wide variety of conditions. Therefore, power supply solutions must be very efficient, provide robust functionality and reliability, while being very compact and cost effective. In terms of driving high-brightness LEDs, the most demanding application is automotive headlight lighting applications, including daytime running lights and headlights, because such applications are in a harsh automotive electrical environment, the wattage of the high beam and the low beam of the automotive headlight is generally about 55W, but the current high-power driving power supply of the LED automotive headlight has low working efficiency, large temperature rise, high failure rate, high cost and many potential safety hazards.

The present chinese patent document discloses an LED automobile high-power driving power supply with application number 201810621465.7, which includes: the LED driving circuit comprises a direct current input circuit, an LC filter circuit, a far and near light current control circuit, an MOS tube driving circuit, a chip driving circuit, a cooling fan driving circuit and an LED output circuit, wherein a first output end of the direct current input circuit is connected with an input end of the LC filter circuit, a second output end of the direct current input circuit is connected with an input end of the far and near light current control circuit, an output end of the LC filter circuit is connected with an input end of the MOS tube driving circuit, the chip driving circuit is respectively connected with the far and near light current control circuit and the MOS tube driving circuit, a VO output end of the MOS tube driving circuit is connected with an input end of the cooling fan driving circuit, and an output end of the MOS tube driving circuit is connected with. Although the patent has the characteristics of wide voltage input and low temperature rise, the MOS tube is controlled to be conducted through the PWM pulse of the control chip, the impedance required for selecting and driving the MOS tube according to the parameter requirements of the high beam and the low beam is very low, if the simple direct use of the PWM pulse of the control chip is difficult to realize, and the PWM pulse has the problems of low corresponding speed and high power consumption of the MOS tube switch due to the change process.

Disclosure of Invention

The utility model provides a contactless heavy current MOS manages drive circuit to the above-mentioned problem that prior art exists. The driving circuit solves the problem of how to realize the quick switching response of the small-current control large-current MOS.

The utility model discloses a following technical scheme realizes: the utility model provides a contactless heavy current MOS pipe drive circuit, includes singlechip and MOS pipe Q2 that is used for driving far and near light lamp, this circuit still includes electric capacity C2, electric capacity C3, resistance R1, triode Q1, four input and not gate module and bridge rectifier module, triode Q1's base is connected to the I/O mouth of singlechip, triode Q1's collecting electrode is connected with the power through resistance R1, and triode Q1's collecting electrode still connects the input of four input and not gate module, triode Q1 projecting pole ground connection, two output of four input and not gate module are respectively through electric capacity C2 and electric capacity C3 connection bridge rectifier module, the grid of MOS pipe Q2 is connected to bridge rectifier module output, the drain connection power of MOS pipe Q2, MOS pipe Q2's source is through connecting load and ground connection.

When the I/O port of the singlechip is at a high level, the triode Q1 is conducted, the collector of the triode Q1 has a low level, the input end of the four-input NAND gate module, which is used for connecting the collector of the triode Q1, is at a low level, one of the two output ends of the four-input NAND gate module is at a high level, and the other one of the two output ends of the four-input NAND gate module is at a low level. At this time, the four-input nand gate module is in a steady state, and the voltage at two output ends of the four-input nand gate module is equivalent to direct current and is isolated by a capacitor C2 and a capacitor C3. The low level is output at the grid of the MOS tube Q2 through the bridge rectification mode, at the moment, the MOS tube Q2 is cut off, and the load lamp is extinguished. When the I/O port of the single chip microcomputer is at a low level, the triode Q1 is cut off, the triode Q1 collects high level, the input end of the four-input NAND gate module, which is used for connecting the collector of the triode Q1, is at a high level, two output ends of the four-input NAND gate module output voltage with high and low jump and opposite levels at the same time, namely when one output end is at a high level, the other output end is at a low level and jumps at the same time, the high level is changed into a low level, the low level is changed into a high level to form oscillation frequency, signals of the two output ends of the four-input NAND gate module are equivalent to form alternating current signals, can smoothly pass through the capacitor C2 and the capacitor C3, and obtain direct current voltage meeting the requirement of driving the MOS transistor Q2 after passing. The MOS transistor Q2 turns on and the load lamp is lit. Therefore, the MOS tube Q2 is driven to be opened by small current control and large current, the switch response speed is high, the power consumption is low, and the switch is contactless and low in noise.

In the above contactless large current MOS transistor driving circuit, the four-input NAND gate module comprises a NAND gate U1A, a NAND gate U1B, a NAND gate U1C and a NAND gate U1D, one input end of the NAND gate U1A is connected with the collector of the transistor Q1, the other input end of the NAND gate U1A is connected with a resistor R4 in series, the output end of the nand gate U1A is respectively connected to two input ends of the nand gate U1B and two input ends of the nand gate U1C, the output end of the NAND gate U1B is connected with two input ends of the NAND gate U1D, the output end of the NAND gate U1A is also connected with a resistor R5 in parallel, the resistor R4 is connected with a resistor R5 to form a loop, the output end of the NAND gate U1B is also connected with a capacitor C1 in parallel, the capacitor C1 is connected with a resistor R5 to form a loop, the output end of the nand gate U1C is connected to one leg of the bridge rectifier module through a capacitor C2, and the output end of the nand gate U1D is connected to the other leg of the bridge rectifier module through a capacitor C3.

Through the connection circuit of the NAND gates U1A, U1B and U1D through the resistor R4, the resistor R5 and the capacitor C1, when the collector of the transistor Q1 is turned on, the NAND gate U1A outputs a high level, the circuit is in a steady state, the NAND gate U1C outputs a low level, the NAND gate U1D outputs a high level, the polarity of the capacitor C1 is up negative and down positive, the MOS transistor Q2 is turned off, when the transistor Q1 is turned off, the capacitor C1 realizes the charging and discharging processes, high voltage jumps of the NAND gates U1C and U1D are caused, and the output levels of the NAND gates U1C and U1D are logically inverted. The output ends of the NAND gate U1C and the NAND gate U1D form an alternating current signal with certain amplitude. Therefore, when the transistor Q1 is cut off, the output alternating current signal is connected with the circuit of the four-input NAND module, and the direct current voltage is obtained by the bridge rectifier module to drive the MOS transistor Q2. The MOS tube Q2 driving circuit formed by the triode Q1 and the four-input NAND gate module has high oscillation frequency, the voltage loaded on the grid electrode and the source electrode of the MOS tube Q2 after rectification is large, and the power consumption of the MOS tube Q2 during starting is low.

In the above contactless large current MOS tube driving circuit, the circuit further includes a resistor R2 and a resistor R3, the base of the transistor Q1 is connected to the I/O port of the single chip microcomputer through the resistor R3, and the emitter of the transistor Q1 is grounded through the resistor R2. The resistor R3 is used for preventing the signal source from overloading, changing the current output of the signal source into voltage output, and forming voltage drop on the resistor R3, so that the impedance on the base electrode of the triode Q1 is matched, and the triode Q1 can be driven better. Meanwhile, the resistor R2 makes the transistor Q1 more stable in the long-term operation process.

In the above contactless large-current MOS transistor driving circuit, the output end of the bridge rectifier module is connected in parallel with a resistor R6, and a resistor R6 is connected to the gate and the source of the MOS transistor Q2. The voltage formed across the resistor R6 is the voltage formed between the gate and the source of the MOS transistor Q2, so that the impedance of the MOS transistor Q2 is matched. The resistor R6 has a voltage larger than 5V and the closer to the power supply voltage, the lower the turn-on loss of the MOS transistor Q2 is, so that the circuit has the MOS transistor Q2 driving function with low power consumption and quick response.

In the contactless large-current MOS tube driving circuit, the four-input NAND module is a 4011BD integrated chip. The 4011BD integrated chip is internally provided with four NAND gates, each NAND gate is provided with two input ends, and the integrated chip can realize the logic NAND function. And circuit components are reduced through the highly integrated chip, so that the high-beam and low-beam LED lamp can be more suitable for the working environment limited by the high-beam and low-beam lamps.

In the above contactless large current MOS transistor driving circuit, the MOS transistor Q2 is an LR7843 series field effect transistor. The LR7843 series field effect transistor has high-frequency synchronous voltage reduction, a computer processor power converter and high-frequency isolation type DC-DC, can realize a synchronous rectification function, has the maximum voltage of a drain electrode and a source electrode of 30V, has lower starting voltage, and can better drive the high beam and the low beam of an automobile by the current of the drain electrode and the source electrode after being conducted.

Compared with the prior art, the non-contact large-current MOS tube driving circuit is provided. Has the following advantages:

1. the utility model discloses drive circuit realizes that undercurrent control heavy current drive MOS pipe Q2 opens, and switch response speed is fast, and the low-power consumption, contactless low noise, and work efficiency is high.

2. The utility model discloses a triode Q1 and four inputs and the MOS pipe Q2 drive circuit that the NAND gate module formed, oscillation frequency is high, and the loading is great at the voltage of MOS pipe Q2 grid and source electrode after the rectification, the low power dissipation of opening of MOS pipe.

3. The utility model discloses use 4011BD NULL as four inputs and not door module, integrated degree is high, powerful for this drive circuit simple structure, the circuit is compact, is applicable to and sets up in the crowded lamp shade of far and near light.

Drawings

Fig. 1 is a schematic circuit diagram of the present invention.

In the figure, 1, a single chip microcomputer; 2. a bridge rectifier module; 3. and the four-input NAND gate module.

Detailed Description

The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described with reference to the accompanying drawings, but the present invention is not limited to these embodiments.

As shown in fig. 1, the contactless large-current MOS transistor driving circuit includes a single chip microcomputer 1, a capacitor C2, a capacitor C3, a resistor R1, a triode Q1, a four-input nand gate module 3, a bridge rectifier module 2, and a MOS transistor Q4 for driving a high beam and a low beam, an I/O port of the single chip microcomputer 1 is connected to a base of a triode Q1, a collector of the triode Q1 is connected to a power supply through the resistor R1, a collector of the triode Q1 is further connected to an input terminal of the four-input nand gate module 3, an emitter of the triode Q1 is grounded, two output terminals of the four-input nand gate module 3 are respectively connected to the bridge rectifier module 2 through the capacitor C2 and the capacitor C3, an output terminal of the bridge rectifier module 2 is connected to a gate of a MOS transistor 737q 3, a drain of the MOS transistor Q2 is connected to. The circuit further comprises a resistor R2 and a resistor R3, the base electrode of the triode Q1 is connected with the I/O port of the singlechip 1 through the resistor R3, and the emitter electrode of the triode Q1 is grounded through the resistor R2. The resistor R3 is used for preventing the signal source from overloading, changing the current output of the signal source into voltage output, and forming voltage drop on the resistor R3, so that the impedance on the base electrode of the triode Q1 is matched, and the triode Q1 can be driven better. Meanwhile, the resistor R2 ensures that the triode Q1 works for a long time

The four-input nand gate module 3 comprises a nand gate U1A, a nand gate U1B, a nand gate U1C and a nand gate U1D, one input end of the nand gate U1A is connected with a collector of a transistor Q1, the other input end of the nand gate U1A is connected with a resistor R4 in series, an output end of the nand gate U1A is respectively connected with two input ends of a nand gate U1B and two input ends of a nand gate U1C, an output end of the nand gate U1B is connected with two input ends of a nand gate U1D, an output end of the nand gate U1A is also connected with a resistor R5 in parallel, a resistor R4 is connected with the resistor R5 to form a loop, an output end of the nand gate U1B is also connected with a capacitor C1 in parallel, a capacitor C1 is connected with the resistor R5 to form a loop, an output end of the nand gate U1C is connected with one bridge arm of the rectifier.

The output end of the bridge rectifier module 2 is connected in parallel with a resistor R6, and a resistor R6 is connected with the gate and the source of the MOS transistor Q2. The voltage formed across the resistor R6 is the voltage formed between the gate and the source of the MOS transistor Q2, so that the impedance of the MOS transistor Q2 is matched. The resistor R6 has a voltage larger than 5V and the closer to the power supply voltage, the lower the turn-on loss of the MOS transistor Q2 is, so that the circuit has the MOS transistor Q2 driving function with low power consumption and quick response. The four-input NAND gate module 3 is a 4011BD integrated chip. The 4011BD integrated chip is internally provided with four NAND gates, each NAND gate is provided with two input ends, and the integrated chip can realize the logic NAND function. And circuit components are reduced through the highly integrated chip, so that the high-beam and low-beam LED lamp can be more suitable for the working environment limited by the high-beam and low-beam lamps. The MOS transistor Q2 is an LR7843 series field effect transistor. The LR7843 series field effect transistor has high-frequency synchronous voltage reduction, a computer processor power converter and high-frequency isolation type DC-DC, can realize a synchronous rectification function, has the maximum voltage of a drain electrode and a source electrode of 30V, has lower starting voltage, and can better drive the high beam and the low beam of an automobile by the current of the drain electrode and the source electrode after being conducted. The bridge rectifier module 2 comprises a diode D1, a diode D2, a diode D3 and a diode D4, wherein the anode of the diode D1 and the cathode of the diode D3 are connected in series to form one bridge arm of the bridge rectifier module 2, the anode of the diode D2 and the cathode of the diode D4 are connected in series to form the other bridge arm of the bridge rectifier module 2, the cathode of the diode D1 is connected with the cathode of the diode D2, and the anode of the diode D3 is connected with the anode of the diode D4.

When the I/O port of the single chip microcomputer 1 is at a high level, the triode Q1 is turned on, the collector of the triode Q1 is at a low level, the input end of the four-input nand gate module 3, which is used for connecting the collector of the triode Q1, is at a low level, one of the two output ends of the four-input nand gate module 3 is at a high level, and the other is at a low level. At this time, the four-input nand gate 3 is in a steady state, and the voltages at the two output ends of the four-input nand gate are isolated by the capacitor C2 and the capacitor C3, which are equivalent to direct current. The low level is output at the grid of the MOS tube Q2 through the bridge rectification mode, at the moment, the MOS tube Q2 is cut off, and the load lamp is extinguished. When the I/O port of the single chip microcomputer 1 is at a low level, the transistor Q1 is turned off, the transistor Q1 collects a very high level, the input end of the four-input nand gate module 3 for connecting the collector of the transistor Q1 is at a high level, two output ends of the four-input nand gate module 3 output voltage levels with high and low jumps and logic opposite levels at the same time, namely, when one output is at a high level, the other output end is at a low level and jumps at the same time, the high level changes into a low level, the low level changes into a high level to form oscillation frequency, signals at two output ends of the four-input nand gate module 3 equivalently form alternating current signals, can smoothly pass through the capacitor C2 and the capacitor C3, and obtain direct current voltage meeting the requirement of driving the MOS transistor Q2 after passing through the bridge rectifier. The MOS transistor Q2 turns on and the load lamp is lit. Therefore, the MOS tube Q2 is driven to be opened by small current control and large current, the switch response speed is high, the power consumption is low, and the switch is contactless and low in noise.

Specifically, through the connection circuit of the nand gate U1A, the nand gate U1B, the nand gate U1D, the resistor R4, the resistor R5 and the capacitor C1, when the collector of the transistor Q1 is turned on, the nand gate U1A outputs a high level, the circuit is in a steady state, the nand gate U1C outputs a low level, the nand gate U1D outputs a high level, at this time, the polarity of the capacitor C1 is positive, negative and positive, at this time, the MOS transistor Q2 is turned off, when the transistor Q1 is turned off, the capacitor C1 realizes the charging and discharging processes, the high-voltage jumps of the nand gate U1C and the nand gate U1D are caused, and the output levels of the nand gate U1C and the nand gate. The output ends of the NAND gate U1C and the NAND gate U1D form an alternating current signal with certain amplitude. Therefore, when the triode Q1 is cut off, the output alternating current signal is connected with the four-input nand module through the circuit, and the direct current voltage is obtained through the bridge rectifier module 2 to drive the MOS transistor Q2. The MOS tube Q2 driving circuit formed by the triode Q1 and the four-input NAND module 3 has high oscillation frequency, the voltage loaded on the grid electrode and the source electrode of the MOS tube Q2 after rectification is large, and the turn-on power consumption of the MOS tube Q2 is low. In the figure, X1 represents a load, i.e., a high beam and a low beam. VCC is the power supply identification.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications, additions and substitutions for the specific embodiments described herein may be made by those skilled in the art without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.

Claims (6)

1. A non-contact large-current MOS tube driving circuit comprises a singlechip (1) and an MOS tube Q2 for driving a high beam and a low beam, the circuit is characterized by further comprising a capacitor C2, a capacitor C3, a resistor R1, a triode Q1, a four-input NAND gate module (3) and a bridge rectifier module (2), the I/O port of the singlechip (1) is connected with the base electrode of a triode Q1, the collector electrode of the triode Q1 is connected with a power supply through a resistor R1, and the collector of the triode Q1 is also connected with the input end of the four-input NAND gate module (3), the emitter of the triode Q1 is grounded, two output ends of the four-input NAND gate module (3) are respectively connected with the bridge rectifier module (2) through a capacitor C2 and a capacitor C3, the output end of the bridge rectifier module (2) is connected with the grid of the MOS tube Q2, the drain of the MOS tube Q2 is connected with a power supply, and the source of the MOS tube Q2 is connected with a load and grounded.

2. A contactless high-current MOS tube driving circuit according to claim 1, the four-input NAND gate module (3) comprises a NAND gate U1A, a NAND gate U1B, a NAND gate U1C and a NAND gate U1D, one input end of the NAND gate U1A is connected with the collector of the transistor Q1, the other input end of the NAND gate U1A is connected with a resistor R4 in series, the output end of the nand gate U1A is respectively connected to two input ends of the nand gate U1B and two input ends of the nand gate U1C, the output end of the NAND gate U1B is connected with two input ends of the NAND gate U1D, the output end of the NAND gate U1A is also connected with a resistor R5 in parallel, the resistor R4 is connected with a resistor R5 to form a loop, the output end of the NAND gate U1B is also connected with a capacitor C1 in parallel, the capacitor C1 is connected with a resistor R5 to form a loop, the output end of the NAND gate U1C is connected with one bridge arm of the bridge rectifier module (2) through a capacitor C2, the output end of the NAND gate U1D is connected with the other bridge arm of the bridge rectifier module (2) through a capacitor C3.

3. The contactless large current MOS tube driving circuit according to claim 1 or 2, further comprising a resistor R2 and a resistor R3, wherein the base of said transistor Q1 is connected to the I/O port of the single chip microcomputer (1) through the resistor R3, and the emitter of said transistor Q1 is grounded through the resistor R2.

4. The contactless large-current MOS tube driving circuit according to claim 1 or 2, wherein the output end of the bridge rectifier module (2) is connected with a resistor R6 in parallel, and a resistor R6 is connected with the gate and the source of a MOS tube Q2.

5. The contactless large-current MOS tube driving circuit according to claim 1, wherein the four-input NAND module (3) is a 4011BD integrated chip.

6. The contactless large-current MOS tube driving circuit according to claim 1, wherein the MOS tube Q2 is an LR7843 series field effect tube.

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