KR20100118178A - Mosfet driver of motor driver for a fuel pump - Google Patents

Abstract

PURPOSE: A MOSFET driver circuit is provided to simplify a circuit by removing a push-pull transistor and a bypass condenser. CONSTITUTION: A first MOSFET driving part(51) turns on and off the first MOSFET of a motor driver. The first MOSFET driving part comprises a first and second transistor, and a first resistor. A second MOSFET driving part(53) turns on and off the second MOSFET of the motor driver. The second MOSFET driving part comprises a third and fourth transistor, and a second resistor. A voltage doubling part doubles a DC driving voltage for driving the first and the second MOSFET driving part.

Description

MOSFET driver circuit of motor drive device for fuel pump {MOSFET DRIVER OF MOTOR DRIVER FOR A FUEL PUMP}

The present invention relates to a motor driving apparatus for a fuel pump, and more particularly, to a fuel pump motor driving apparatus capable of simplifying the configuration of a driving circuit for driving a MOSFET to output an on / off switching signal to a fuel pump motor. It relates to a MOSFET driving circuit.

In general, a vehicle using liquefied petroleum gas (LPG) as a fuel supplies an engine with LPG fuel stored in a fuel tank by using a fuel pump. At this time, the amount of LPG supplied to the engine is adjusted by controlling the rotational speed of the fuel pump in consideration of the speed of the vehicle.

Recently, a liquefied petroleum injection (LPI) engine that directly injects the liquefied petroleum gas into the engine in a liquid state has been developed. These LPI engines can improve engine output by 10-20% and reduce pollutant emissions compared to conventional engines that use liquid LPG fuel mixed with air.

The motor that drives the fuel pump uses a brushless direct current motor (BLDC) to secure high efficiency, long life, and reliability. In particular, a sensorless BLDC motor is used. It is common to use.

The technology of the driving circuit of the motor driving device for driving the fuel pump for supplying the LPG fuel is well shown in Korean Utility Model Application No. 20-2008-0011881. Therefore, only parts related to the present invention will be described in FIGS. 1 and 2 and other detailed descriptions will be omitted.

1 is a block diagram showing a configuration of a motor driving apparatus for a fuel pump according to the prior art, and FIG. 2 is a detailed circuit diagram showing a circuit configuration of the gate driver shown in FIG.

First, a configuration of a motor driving apparatus for a fuel pump according to the prior art will be described with reference to FIG. 1.

As shown in FIG. 1, the fuel pump motor driving apparatus 1 according to the related art includes an interface 10, an MCU 20, an overvoltage protection unit 30, a motor controller 40, and a MOSFET driving circuit 50. ) And the motor driver 60.

Here, the motor driving unit 60 is formed in a three-phase full bridge method to perform a switching role for transmitting a driving signal to the motor M driving the fuel pump. The motor driver 60 includes a P-channel MOSFET on a high side to which a driving signal for driving a motor M of a large vehicle using a driving power of 24V is input. In addition, an N-channel MOSFET is provided on a low side to which a driving signal for driving a motor applied to a passenger vehicle using a 12V driving power source is input. The MOSFET driving circuit 50 includes a driver circuit (Gate Driver IC) which will be described below in order to transmit a control signal to each of the MOSFET devices.

The motor controller 40 receives the current speed of the motor M measured by the motor driver 60 and transmits the current speed to the MCU 20.

Then, the MCU 20 calculates an error between the transmitted current speed and the target speed, and performs proportional integral control based on the calculated error. In addition, the MCU 20 outputs a control signal for the calculated error to the motor controller 40 to transmit a feedback signal to the motor M. FIG.

Accordingly, the fuel pump motor driving apparatus 1 controls the error of the current speed and the target speed of the motor M to be minimized, and controls the fuel to be properly supplied to the engine according to the state of the vehicle.

Next, the MOSFET driving circuit 50 may include a first MOSFET driver 51 for driving an N-channel MOSFET according to the high side signal, and a second MOSFET for driving an N-channel MOSFET according to the low side signal. And a voltage multiplier 55 for supplying a power multiplied by 24V to the driver 53 and the first MOSFET drivers 51 and 53.

Next, a configuration of the MOSFET driving circuit 50 will be described with reference to FIG. 2.

As shown in FIG. 2, the first MOSFET driver 51 receives a multiplier voltage VCC2 boosted to 24V from the voltage multiplier 55, and the second MOSFET driver 53 receives a DC driving voltage of 12V. Receive (VCC) input. Here, a high side signal is input to the first MOSFET driver 51, a low side signal is input to the second MOSFET driver 53, and the motor driver 60 is input according to each signal. Control on / off.

First, when looking at the first transistor Q5 to which the low side signal is input, 5V is applied to the base of the first transistor Q5, and power is supplied through the collector of the first transistor Q5. Current flows through the collector and emitter. Then, the emitter of the first transistor Q5 takes about 4.3V minus 0.7V, which is the threshold voltage between the base and the emitter. Therefore, current flows to the emitter of the first transistor Q5 by the resistor R8. The emitter of the second transistor Q6 receives a constant voltage so that a current flows through the resistor R6. Accordingly, the third transistor Q7 is turned on and the fourth transistor Q8 is turned off, so that the voltage VCC is applied to the gate of the N-channel second MOSFET 63.

On the contrary, when the low side signal is not input, 0 V is applied to the base of the first transistor Q5, and the voltage applied to the collector of the first transistor Q5 is DC driving power supply VCC. Is applied. Since power is applied to the base of the second transistor Q6, the second transistor Q6 is turned off or maintained off, and thus the collector voltage of the second transistor Q6 becomes 0V. Accordingly, the NPN type third transistor Q7 is turned off because the voltage applied to the base is 0V, and the PNP type fourth transistor Q8 is turned on because the voltage applied to the base is 0V. 0V is applied to the gate of 63).

Next, when the fifth transistor Q1 to which the high side signal is input is viewed, when the high side signal is not input, when 5 V is applied to the base of the fifth transistor Q1, the fifth transistor Q1 is input. About 4.3V is applied to the emitter of the transistor Q1, and a current flows to the emitter by a resistor (not shown) connected to the emitter. A voltage is applied to the collector of the fifth transistor Q1 by the resistor R1, and a current applied to the emitter of the sixth transistor Q2 is formed by the resistor R2. Accordingly, the seventh transistor Q3 of the NPN type is turned on, the eighth transistor Q4 of the PNP type is turned off, and the emitter voltage of the eighth transistor Q4 is set to the gate of the N-channel first MOSFET 61. Is approved.

On the contrary, when a high side signal is input, 5 V is applied to the base and the emitter of the fifth transistor Q1, and the collector voltage of the fifth transistor Q1 is the voltage multiplier 55. Since VCC2 is applied from, the sixth transistor Q2 is turned off. Since the collector voltage of the sixth transistor Q2 is the same as that of the eighth transistor Q4, the seventh transistor Q3 is turned on, and the eighth transistor Q4 is turned off to form the N-channel first MOSFET. The collector voltage of the eighth transistor Q4 is applied to the gate terminal of 61.

Accordingly, the N-channel MOSFETs 61 and 63 of the motor driver 60 are turned on / off according to the high side signal and the low side signal, thereby turning the motor driver 60 off. It is operated to supply a controlled voltage to the fuel pump motor (M) through.

However, the MOSFET driving circuit of the conventional fuel pump motor driving apparatus as described above has the following problems.

First, in the third and fourth transistors Q7 and Q8 and the seventh and eighth transistors Q3 and Q4 constituting the push-pull circuit, a noise current is generated by the on / off time difference. .

In addition, the fourth and eighth transistors Q8 and Q4 have a limit in that the gate voltage of the MOSFET cannot be completely removed.

In addition, the capacitors C4 and C6 in the bypass path formed at the gate end of the MOSFET form a gentle slope of the gate switching signal, thereby reducing the lifetime of the MOSFET and reducing unnecessary elements such as the resistor R8. There is a problem that the manufacturing cost of the circuit is increased.

The present invention is to solve the problems described above, an object of the present invention is to simplify the configuration of the MOSFET drive circuit for driving a motor for a fuel pump while driving the MOSFET drive circuit of the fuel pump motor drive device that can improve the operating characteristics To provide.

According to a feature of the present invention for achieving the above object, the present invention provides a fuel for controlling the MOSFET of the motor drive unit by the control signal of the motor controller for outputting a control signal for driving the fuel pump motor in accordance with the vehicle speed A MOSFET driving circuit of a motor driving apparatus for a pump, comprising: a first MOSFET driving unit for turning on and off a first MOSFET of the motor driving unit, a second MOSFET driving unit for turning on and off a second MOSFET of the motor driving unit, and a DC driving voltage; A voltage multiplier for multiplying a voltage level to be applied to the first MOSFET driver, wherein the first MOSFET driver includes first and second transistors and a first resistor, and the second MOSFET driver includes third and fourth transistors and a second resistor. Includes resistance.

The first transistor receives a high side signal at an emitter terminal, a device driving voltage is applied to a base terminal, and the second transistor is an input terminal of a power doubled from the collector terminal of the first transistor and the voltage multiplier. The base terminal is connected between the multiplier and the collector terminal of the first transistor and the emitter terminal of the second transistor are characterized in that the doubled power is applied.

The first resistor may be provided between the collector terminal of the second transistor and the gate terminal of the first MOSFET.

The third transistor has a low side signal input to a base end and a DC driving voltage is applied to a collector end, and the fourth transistor has a base end between a collector end of the third transistor and an input end of the DC driving voltage. The DC driving voltage is applied to the collector terminal of the third transistor and the emitter of the fourth transistor.

The second resistor may be provided between the collector terminal of the fourth transistor and the gate terminal of the second MOSFET.

As described above, the present invention can perform precise control of the product by removing the push-pull transistor which generates a noise current and retains the gate voltage of the MOSFET, thereby improving operating characteristics.

In addition, since unnecessary elements such as push-pull transistors and resistors can be removed, the circuit configuration can be simplified and the life of the MOSFET can be extended, thereby reducing the cost of the circuit configuration.

Hereinafter, a MOSFET driving circuit of a motor driving apparatus for a fuel pump according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a detailed circuit diagram of a MOSFET driving circuit of a fuel pump motor driving apparatus according to an exemplary embodiment of the present invention.

In the exemplary embodiment of the present invention, the same parts as in the prior art are denoted by the same reference numerals, and repeated description thereof will be omitted.

The MOSFET driving circuit 50 of the fuel pump motor driving apparatus according to the present invention includes a first MOSFET driving unit 51 for driving a high side N-channel MOSFET, and a second MOSFET driving unit for driving a LOW SIED N-channel MOSFET ( 53). In the present exemplary embodiment, the first and second MOSFET drivers 51 and 53 are not gate driver integrated circuits (ICs) configured as single chips, but individual transistor circuits. The individual unit cost of the motor drive is reduced. A voltage multiplier 55 is provided to double the DC driving voltage for driving the individual transistor circuits of the first and second MOSFET drivers 51 and 53. That is, as the voltage doubling unit 55 boosts the voltage of 12V to 24V, the MOSFET driving circuit 50 may be applied to a large commercial vehicle system based on a 24V voltage as well as a passenger vehicle system based on a 12V voltage. have. Detailed description of the configuration of the voltage multiplier 55 will be omitted.

Next, the configuration of the first and second MOSFET drivers 51 and 53 will be described in detail with reference to FIG. 3.

As shown in FIG. 3, the first MOSFET driver 51 receives a double voltage VCC2 of which the voltage double is boosted from the unit 55 to 24V, and the second MOSFET driver 53 is a DC driving voltage of 12V. (VCC) is authorized.

In addition, the first MOSFET driver 51 receives a high side signal, the second MOSFET driver 53 receives a low side signal, and the first and second MOSFET drivers 51, 53 respectively controls on / off of the first and second MOSFETs 61 and 63 of the motor driver 60 according to the input signal.

In this embodiment, two transistors are respectively used in the first and second MOSFET drivers 51 and 53 to implement a driving circuit having the same function as a gate driver IC.

First, referring to the configuration of the first MOSFET driver 51, the high side signal is input to the emitter terminal and a first transistor Q11 is applied to the base terminal to which the device driving voltage of 5V is applied. A second transistor Q12 is connected between a collector terminal of the first transistor Q11 and an input terminal of a double voltage VCC2 boosted to 24V from the voltage doubler 55.

The first resistor R11 and the second resistor R12 are parallel to each other between the input terminal of the double voltage VCC2 and the collector terminal of the first transistor Q11 and the emitter terminal of the second transistor Q12. Is connected to. A third resistor R13 is provided between the collector terminal of the second transistor Q12 and the gate terminal of the first MOSFET 63.

Next, referring to the configuration of the second MOSFET driver 53, a third transistor Q21 having a low side signal input to a base terminal and a 12 V DC driving voltage VCC applied to a collector terminal is provided. do. The base terminal is connected to the collector terminal of the third transistor Q21, and the fourth transistor Q22 to which the DC driving voltage VCC is applied is provided at the emitter terminal.

A fourth resistor R14 and a fifth resistor R15 are parallel to each other between the input terminal of the DC driving voltage VCC and the collector terminal of the third transistor Q21 and the emitter terminal of the fourth transistor Q22, respectively. Is connected to. A sixth resistor R16 is provided between the collector terminal of the fourth transistor Q22 and the gate terminal of the second MOSFET 63.

Next, the configuration of the motor driver 60 will be briefly described. The motor driver 60 may include first and second MOSFETs 61 and 63 between an input terminal of the DC driving voltage VCC and a ground potential line GND. ) Is provided. The first and second MOSFETs 61 and 63 output on / off driving signals for controlling the driving of the motor M according to signals output from the first and second MOSFET drivers 51 and 53.

Hereinafter, the operation of the MOSFET driving circuit of the motor driving apparatus for the fuel pump according to the preferred embodiment of the present invention having the configuration as described above.

First, the operation of the first MOSFET driver 51 will be described.

When the high side signal is input to the emitter terminal of the first transistor Q11, the device driving voltage VDD and the double voltage of 24 V are applied to the base terminal and the collector terminal of the first transistor Q11, respectively. ) Is always input, so that the collector and emitter of the first transistor Q11 do not conduct. Therefore, since the double voltage is applied to both the base terminal and the emitter terminal of the second transistor Q12, the second transistor Q12 is turned off or remains off. Accordingly, the first MOSFET 61 outputs an off drive signal for stopping the driving of the motor M. FIG.

On the other hand, when the HIGH SIDE signal is not input, the collector and the emitter of the first transistor Q11 become conductive so that the emitter of the first transistor Q11 is connected to the base- at the double voltage VCC2 of 5V. It takes about 4.3V minus the threshold voltage (0.7V) between emitters. Accordingly, as the first transistor Q11 is turned on, the emitter and the collector of the second transistor Q12 are turned on so that the second transistor Q12 is turned on. Accordingly, the first MOSFET 61 receiving the doubled voltage VCC2 through the third resistor R13 to the gate outputs an on driving signal to drive the motor M. Referring to FIG.

Next, the operation of the second MOSFET driver 53 will be described.

When the low side signal is input to the base terminal of the third transistor Q21, since the 12 V DC driving voltage VCC is constantly input to the collector terminal of the third transistor Q21, the third transistor Q21 ) Collector and emitter are conducting. Accordingly, the emitter and the collector of the fourth transistor Q22 are conducted so that the fourth transistor Q22 is turned on. Accordingly, the second MOSFET 63 outputs an on drive signal for driving the motor M. As shown in FIG.

On the other hand, when the low side signal is not input, the DC driving voltage VCC is applied to the base terminal and the emitter terminal of the fourth transistor Q22 without conducting the collector and emitter of the third transistor Q21. I get caught. Therefore, as the fourth transistor Q22 is turned off or remains off, the collector voltage of the fourth transistor Q22 becomes 0V, so that 0V is also applied to the gate of the second MOSFET 63. As a result, the second MOSFET 63 outputs an off driving signal for stopping the driving of the motor M. FIG.

Through the above process, the present invention eliminates the conventional push-pull transistors and simplifies the circuit configuration, thereby preventing the generation of noise current due to the operation time difference of the push-pull transistors, and reducing the gate voltage of the MOSFET. Can be removed completely In addition, it is possible to extend the lifespan of the first and second MOSFETs by removing the bypass capacitor which makes the slope of the driving signal applied to the gate gentle.

 The scope of the present invention is not limited to the embodiments described above, but is defined by the claims, and various changes and modifications can be made by those skilled in the art within the scope of the claims. It is self evident.

1 is a block diagram showing the configuration of a motor driving apparatus for a fuel pump according to the prior art.

FIG. 2 is a detailed circuit diagram showing a circuit configuration of the gate driver shown in FIG. 1. FIG.

3 is a detailed circuit diagram showing the configuration of a MOSFET driving circuit of a motor driving apparatus for a fuel pump according to a preferred embodiment of the present invention.

`` Explanation of symbols for main parts of drawings ''

1: Motor drive device for fuel pump 10: Interface

20: MCU 30: overvoltage protection

40: motor controller 50: MOSFET driver

51: first MOSFET driver 53: second MOSFET driver

55: voltage multiplier 60: motor drive unit

61: first MOSFET 63: second MOSFET

Q: transistor R: resistance

C: condenser M: motor

Claims (5)

In the MOSFET drive circuit of the fuel pump motor drive device for controlling the MOSFET of the motor drive unit by the control signal of the motor controller for outputting a control signal for driving the fuel pump motor in accordance with the vehicle speed, A first MOSFET driver for turning on / off a first MOSFET of the motor driver; A second MOSFET driver for turning on / off a second MOSFET of the motor driver; A voltage multiplier configured to double the voltage level of the DC driving voltage and apply the multiplied voltage level to the first MOSFET driver; Wherein the first MOSFET driver includes first and second transistors and a first resistor, and the second MOSFET driver includes third and fourth transistors and a second resistor. . The method of claim 1, In the first transistor, a high side signal is input to an emitter terminal and a device driving voltage is applied to a base terminal. The second transistor has a base terminal coupled between the collector terminal of the first transistor and the input terminal of the power doubled from the voltage multiplier, The MOSFET driving circuit of the motor driving apparatus for a fuel pump, characterized in that the doubled power is applied to the collector stage of the first transistor and the emitter stage of the second transistor. The method of claim 2, wherein the first resistor is And a MOSFET driving circuit provided between the collector terminal of the second transistor and the gate terminal of the first MOSFET. The method according to any one of claims 1 to 3, In the third transistor, a low side signal is input to the base terminal and a DC driving voltage is applied to the collector terminal. The fourth transistor has a base terminal connected between the collector terminal of the third transistor and the input terminal of the DC driving voltage, And a direct current driving voltage is applied to the collector stage of the third transistor and the emitter of the fourth transistor. The method of claim 4, wherein the second resistor is And a MOSFET driving circuit provided between the collector terminal of the fourth transistor and the gate terminal of the second MOSFET.

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