KR100501761B1 - Driving circuit for use in thermo control - Google Patents

Abstract

A load control circuit for a thermo control that operates adaptively according to the type of load and can reduce power consumption and device size is disclosed. Such a thermo-control load drive circuit includes at least one load connection line; A driving control unit for generating a control signal for operation of the load by comparing a reference signal and an oscillation signal to perform a thermo control operation on a load to be connected to the load connection line; A load driver which drives a load connected in response to a control signal of the drive controller; And a mode determination unit for outputting different status signals according to the type of load connected to the load connection line to change the level of the reference signal.

Description

Driving circuit for thermo control {Driving circuit for use in thermo control}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermo control suitable for use in cold and hot equipment such as air conditioners, heaters, refrigerators, and the like, and more particularly, to a load drive circuit for a thermo control.

In general, when continuously operating the compressor employed in the air conditioner of the cold and warm equipment there is a problem that the intake of indoor air is blocked by the ice in the indoor air inlet pipe. Therefore, in order to solve such a problem, a temperature sensor is attached to the indoor air inlet, and when the temperature falls below a certain temperature, the external relay is shut off to stop the operation of the compressor, and when the temperature rises above a certain temperature, an external relay is connected. It is equipped with a thermo control circuit which restarts the compressor.

Such a thermo control circuit generally comprises a temperature sensor section and a load driving circuit for controlling the driving of the relay from the temperature information of the temperature sensor. In this case, the load driving circuit is usually designed to be suitable when the type of load is a relay because the load is controlled by a pulse width modulation method. Therefore, it is not very suitable for driving a linear load such as an engine control unit (ECU), etc., and there is a burden of manufacturing a separate load driving circuit if necessary.

In addition, when an ordinary relay load driving circuit or ECU load driving circuit is applied without distinction without knowing the type of the load connected to the load driving circuit, malfunction control may occur or damage to circuit components may occur. There is a serious problem.

In addition, there has been a problem in that it is difficult to reduce the size of the element employed in the control of the pulse code modulation (PWM) method and the power consumption is a burden accordingly.

Accordingly, an object of the present invention is to provide an improved thermo-control load driving circuit which can solve the above-mentioned conventional problems.

Another object of the present invention is to provide a load control circuit for a thermo control that can be adaptively operated according to the type of load.

Still another object of the present invention is to provide a load control circuit for a thermo control capable of reducing power consumption and device size.

Another object of the present invention is to provide a thermo control circuit capable of one-chip load driving circuit.

According to an aspect of the present invention, a load control circuit for a thermo control includes: at least one load connection line; A driving control unit for generating a control signal for operation of the load by comparing a reference signal and an oscillation signal to perform a thermo control operation on a load to be connected to the load connection line; A load driver which drives a load connected in response to a control signal of the drive controller; And a mode determination unit for outputting different status signals according to the type of load connected to the load connection line to change the level of the reference signal.

The mode determiner may include two transistors and one resistor, and the transistors may be turned on according to the type of load to be connected to make the level of the reference signal at ground potential.

Here, the type of load basically includes an engine control unit and a relay, and the driving controller includes: a regulator for generating a constant voltage; A first comparing unit which receives the constant voltage as an operating power supply voltage and generates a comparison output comparing the sensed voltage signal with a reference voltage signal; And a second comparator configured to receive the comparison output of the first comparator as an operating power supply voltage and to generate a control signal for operation of the load by comparing the oscillation signal output from the oscillator and the applied reference signal.

The load driver may include first, second, and third transistors, three resistors, and a zener diode.

Preferably, the electronic device may further include a thermal shutdown unit configured to receive the constant voltage of the regulator and discharge a potential of the output terminal of the second comparator to ground when a circuit overheat occurs due to a temperature abnormality. In this case, an overvoltage detector for discharging the potential of the output terminal of the second comparator to ground may be further provided. In addition, to protect the internal circuit elements in the event of a short circuit in the load may be further provided with an element protection unit connected to the load connection line to increase the level of the reference signal, by providing a reference voltage by dividing the power supply voltage The apparatus may further include a comparison voltage generator configured to generate the reference signal having a nonlinear output when the voltage exceeds a predetermined voltage.

According to the circuit configuration described above, there is an advantage that can be adaptively operated according to the type of load, and power consumption and device size can be reduced.

Hereinafter, a load control circuit for a thermo control according to a preferred embodiment of the present invention will be described in detail with reference to the drawings without intending to limit the present invention.

First, Figure 1 is a load control circuit diagram for a thermo control according to an embodiment of the present invention. Referring to the drawing, the thermo control circuit is largely divided into a temperature sensor unit 36 and a load driving circuit 50, and the temperature sensor unit 36 is divided into four resistors R5-R9 and thermistor THR. Configured to input a constant voltage Vref through the terminal CN1 to output a sensing voltage signal Vin- representing the result of sensing the temperature through the terminal CN4, and output a reference voltage signal Vin + to the terminal CN3. )

The load driving circuit 50 has a load control line connected to terminals CN8 and CN9 to which different types of loads can be selectively connected, and a thermo control for the load to be selectively connected to the load connection line. A drive control unit for generating a control signal for operation of the load by comparing a reference signal and an oscillation signal to perform an operation, a load driver for driving a load connected in response to a control signal of the drive control unit, and the load Basically, the mode determination unit 46 outputs different status signals according to the type of load connected to the connection line to change the level of the reference signal.

The driving control unit includes a regulator 31 connected between one end of a resistor R3 connected to a power supply voltage VCC and a ground GND to generate a constant voltage, and receiving the constant voltage as an operating power supply voltage, and receiving the sensed voltage signal and a reference. The first comparator 35 generating a comparison output comparing the voltage signals, and the oscillation signal and the node NO2 received from the oscillator 32 while receiving the comparison output of the first comparator 35 as an operating power supply voltage. And a second comparator 33 for generating a control signal for the operation of the load by comparing the reference signals appearing in FIG.

The load driver 49 for driving loads connectable to the terminals CN8 and CN9 in response to the control signal of the second comparator 33 in the driving control unit may include first, second and third transistors Q1. Q100 and Q3, resistors R100, R102 and R103, a buffer BF1, and a zener diode D3.

On the other hand, the comparison voltage generator 45 receiving the power supply voltage VCC provides a reference signal to the node NO2, and the device protection unit ISC 42 provides a node NO3 to protect circuit elements. Is connected to. In addition, the overvoltage detection unit 47 and the thermal shutdown unit 48 respectively connected to the node NO4 perform the overvoltage detection operation and the thermal shutdown operation, respectively.

A pnp type load transistor Q2 having a base connected to a terminal CN7, receiving a power supply voltage VCC through an emitter, and a collector connected to a terminal CN9 outside the load driving circuit 50, and A diode D1 having a cathode connected to the emitter of the load transistor Q2 and an anode connected to the battery, a cathode connected to the emitter of the load transistor Q2, and an anode connected to the collector of the load transistor Q2 Diode D2 is installed. Here, when the load used is a relay, the control input terminal of the relay 34 is connected to the collector of the load transistor Q2 through the second load node RD2. In addition, even when the load used is an ECU (engine control unit), the ECU is connected to the collector of the load transistor Q2 through the second load node RD2. Meanwhile, only an ECU may be connected to the first load node RD1 connected through the terminal CN9.

FIG. 2 is a detailed example of the comparison voltage generator 45 of FIG. 1. The comparison voltage generator 45 including four resistors R10 to R13 and one npn type transistor Q11 has characteristics similar to the graph G2 of FIG. 6 at the node NO2 of FIG. Provide a reference voltage. FIG. 6 is a diagram for explaining an improvement effect of the comparison voltage generator 45. In FIG. 6, a reference voltage that increases linearly depending on voltage distribution of resistors R1 and R2 is generated. In addition, since the duty ratio of the PWM pulses can be adjusted when the transistor Q11 is used to generate a non-linearly increasing reference voltage, power saving by the hatched region EF is achieved. Improving the duty ratio of the pulse code modulated (PWM) signal also provides the advantage of making the size of the load transistor device compact.

FIG. 3 is a diagram illustrating a specific example of the mode determination unit 46 in FIG. 1 and includes two transistors Q20 and Q21 and one resistor R20. When the pnp type transistor Q20 is turned on or turned off according to the type of load, the npn transistor Q21 is turned on or turned off to generate the potential of the node NO2 by the ground level or the comparison voltage generator 45. The level of the reference signal is maintained as it is. Here, when the type of load is an ECU, both the pnp type transistor Q20 and the npn transistor Q21 are turned on so that the potential of the node NO2 is at ground level, which is a linear operation mode. On the contrary, in the PWM operation mode for driving the relay load, both the pnp type transistor Q20 and the npn transistor Q21 are turned off, and the potential of the node NO2 is generated by the comparison voltage generator 45. It is maintained at the level of the reference signal. Accordingly, the thermo-control load driving circuit according to the embodiment of the present invention can automatically change the operation mode according to the type of load. As a result, by adopting the mode determining unit 46, it is possible to apply and drive all irrespective of the relay or the engine control unit. In addition, even when applied to a state that does not know the type of the load connected to the load driving circuit, the linear mode or the pulse width modulation method of the drive control is automatically performed, so that the malfunction control or damage to the circuit components are fundamental. Of course it is prevented.

FIG. 4 is a detailed example of the overvoltage detector 47 of FIG. 1, and includes two resistors R40 and R41 and one transistor Q40. When an overvoltage is detected by the voltage distribution resistors R40 and R41, the voltage of the detection node ND2 increases, and accordingly, the transistor Q40 is turned on so that the potential of the node is discharged to ground.

FIG. 5 is a diagram illustrating a specific example of a thermal shut down unit 48 of FIG. 1, and includes three resistors R30, R31, and R33 and one transistor Q30. The thermal shut-down unit 48 that receives the constant voltage Vref from the regulator 31 of FIG. 1 functions to discharge a potential of the node NO4 to ground when the overheat occurs due to a temperature abnormality, and cut off the circuit. .

As shown in the drawing of FIG. 1, when the load driving circuit 50 is one-chip, the problem of cost burden and increase of the occupied area is of course solved.

For the basic operation in the circuit of FIG. 1 as described above, reference may be made to the title “relay driving integrated circuit” of 10-2002-0040413 filed Jul. 11, 2002, filed by the present applicant. Only operations that are directly related to the present invention will be described here by way of example.

When the relay 34 is connected as a load to the node RD2 connected through the terminal CN9 as a load, the comparison voltage generator 45 is connected to the node NO2 by the operation of the mode determining unit 46. The set reference signal appears. Accordingly, the second comparator 33 compares the level of the reference signal with the triangular wave signal output from the oscillator 32, and outputs a high logic output signal only in a section in which the signal level of the triangular wave is greater than the level of the reference signal. Output to node NO4. Accordingly, the relay 34 is driven by the PWM method by operating only when the load driver 49 is high logic. In this case, since the non-linear reference signal can be generated by the internal intrinsic operation of the comparison voltage generator 45, the duty ratio of the PWM signal can be adjusted to obtain the effect of power saving as described with reference to FIG. 6. .

On the other hand, when the ECU is connected as a load to the node RD2 connected via the terminal CN9, the potential of the node NO2 is brought to the ground level by the operation of the mode determining section 46. As a result, the reference signal set to the low level without the reference signal set by the comparison voltage generator 45 appears. As a result, the output signal is always at a high level, which is suitable for the linear operation mode. As a result, the load driver 49 operates to normally drive the engine control unit in a linear control manner.

In the above, a preferred embodiment of the present invention has been described as an example of a load driving circuit for controlling an air conditioner employed in an automobile, but a person skilled in the art will recognize the spirit and scope of the present invention as set forth in the claims below. It will be understood that various modifications and variations can be made in the present invention without departing from the scope thereof. For example, a thermo control circuit may be employed in the refrigerator or the heater in addition to the air conditioner, and the detailed configuration of the circuit can be appropriately added or decreased according to the case.

According to the load driving circuit of the present invention as described above, by providing a mode determination unit, there is an effect that can be applied and driven regardless of the relay or the engine control unit. In addition, even when applied to a state that does not know the type of the load connected to the load driving circuit, the linear mode or the pulse width modulation method of the drive control is automatically performed, so that the malfunction control or damage to the circuit components are fundamental. There is an advantage to be avoided. In addition, the duty ratio can be improved during the control of the pulse code modulation (PWM) method, so that the size of the load transistor element can be made compact and power consumption can be reduced.

1 is a load control circuit diagram for a thermo control according to an embodiment of the present invention;

FIG. 2 is a specific example of the comparison voltage generator 45 of FIG. 1.

FIG. 3 is a specific example of the mode determination unit 46 in FIG.

FIG. 4 is a specific example of the overvoltage detector 47 of FIG. 1.

5 is a specific example of the thermal shutdown unit 48 of FIG.

6 is a view provided to explain an improvement effect of the comparison voltage generator 45.

Claims (12)

At least one load connecting line; Drive control unit for generating a control signal for the operation of the load by comparing the reference signal and the oscillation signal in order to make the thermo control operation properly even when a load including an engine control unit or a relay is connected to the load connection line Wow; A load driver for driving a load connected in response to a control signal of the drive controller in one of a linear mode and a pulse width modulation scheme; And a mode determination unit for outputting different status signals according to the type of load connected to the load connection line to change the level of the reference signal. The method of claim 1, wherein the mode determiner comprises two transistors and one resistor, and the transistors are all turned on according to the type of load to be connected to make the level of the reference signal at ground potential. Load control circuit for thermo control. (delete) The method of claim 1, wherein the drive control unit, A regulator for generating a constant voltage; A first comparing unit which receives the constant voltage as an operating power supply voltage and generates a comparison output comparing the sensed voltage signal with a reference voltage signal; And a second comparator configured to receive a comparison output of the first comparator as an operating power supply voltage, and generate a control signal for operation of a load by comparing an oscillation signal output from an oscillator and an applied reference signal. Load driving circuit. The load control circuit of claim 1, wherein the load driver comprises first, second, and third transistors, three resistors, and a zener diode. The thermo-control load of claim 4, further comprising a thermal shutdown unit configured to receive the constant voltage of the regulator and discharge the potential of the output terminal of the second comparator to ground when a circuit overheat occurs due to a temperature abnormality. Driving circuit. The load control circuit as claimed in claim 4, further comprising an overvoltage detector configured to receive the power supply voltage and discharge the potential of the output terminal of the second comparator to ground when an overvoltage is detected. The load control circuit of claim 4, further comprising: an element protection unit connected to the load connection line to increase the level of the reference signal to protect an internal circuit element when a short occurs in a load. The load control circuit as claimed in claim 1, further comprising a comparison voltage generator for providing the reference signal by dividing a power supply voltage and generating the reference signal having a non-linear output when a predetermined voltage or more is exceeded. At least one load connecting line; A comparison voltage generator which provides a reference signal by dividing a power supply voltage and generates the reference signal having a nonlinear output when a predetermined voltage is exceeded; A driving control unit for generating a control signal for the operation of the load by comparing the reference signal and the oscillation signal to perform a thermo control operation on the load to be connected to the load connection line; A load driver for driving a load connected in response to a control signal of the drive controller in one of a linear mode and a pulse width modulation scheme; And a mode determination unit for outputting different status signals according to the type of load connected to the load connection line to change the level of the reference signal. The method of claim 10, wherein the mode determiner is composed of two transistors and one resistor, and the transistors are all turned on according to the type of load to be connected to make the level of the reference signal a ground potential. Load control circuit for thermo control. The load control circuit for thermo-control according to claim 10 or 11, wherein the type of the load basically includes an engine control unit and a relay.