JPH0728531A - Temperature controller - Google Patents

Abstract

PURPOSE:To prevent an effect of the supply voltage variance upon the temperature control precision and to reduce the power consumption with respect to a bridge circuit for temperature control. CONSTITUTION:This controller consists of a constant voltage generating circuit 11, a reference voltage generating circuit 12, a temperature sensor 13, and a comparator 14, and influences of the supply voltage variance and the reference voltage variance are prevented by the bridge circuit constituting the reference voltage generating circuit 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control device,
In particular, the present invention relates to a temperature control device that detects temperature information and compares it with reference temperature data in a single circuit.

[0002]

2. Description of the Related Art When performing temperature control, a method of comparing temperature information of a temperature sensor and a reference voltage created in a temperature control circuit and turning on / off heater power is widely used in various fields. It is used to control various temperatures with a satellite heater control unit.

Conventionally, a constant current circuit 31 shown in FIG. 3 is used to supply a bias current to a temperature sensor 32 as a temperature control device for observation equipment mounted on an artificial satellite, and the output current of the temperature sensor 32 is converted into a current. Many methods have been adopted in which the voltage converted by the voltage conversion circuit 33 is converted and the converted voltage and the reference voltage created by the constant voltage circuit 34 and the reference voltage generation circuit 35 are compared by the comparator 36.

[0004]

In this conventional temperature control device, since the reference voltage generation circuit 35 and the temperature detection circuit of the temperature sensor 32 are independent of each other, the problem that total power consumption increases and the power supply voltage is increased. There is a problem that the temperature control accuracy is lowered when the reference voltage fluctuates due to the fluctuation.

An object of the present invention is to provide a temperature control device which can solve the above-mentioned problems, reduce the influence from the external environment as much as possible, and perform highly accurate temperature control.

[0006]

SUMMARY OF THE INVENTION The present invention comprises means for detecting a temperature with a temperature sensor, means for generating a reference voltage, and
In a temperature control device having a comparator that compares an output voltage of a temperature sensor with a reference voltage, the means for detecting the temperature and the means for generating the reference voltage are constituted by one circuit. .

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the basic construction of a temperature control device of the present invention. The constant voltage generation circuit 11 creates a constant voltage from the power supply voltage of the temperature control device. This constant voltage sends a bias current to the temperature sensor 13 and also serves as a voltage source for producing a reference voltage in the reference voltage generating circuit 12. This constant voltage is also used as the power supply voltage of the comparator 14. The reference voltage generation circuit 12 is the constant voltage generation circuit 1
It is a circuit that generates a reference voltage by resistance division from the constant voltage created in 1. The temperature sensor 13 outputs temperature information to the comparator 14 according to the bias current supplied by the constant voltage generation circuit 11. The comparator 14 compares the reference voltage supplied by the reference voltage generation circuit 12 and the temperature sensor output voltage supplied by the temperature sensor 13, and outputs ON / OFF information to the control switch circuit and the heater drive circuit 15. .

FIG. 2 is a specific circuit diagram of an embodiment of the temperature control device of the present invention. This temperature control device has a constant voltage generation circuit having a resistor R1 and a zener diode D, which is connected to a power supply voltage. The constant voltage is supplied to the comparator 14 as a power supply voltage, and the resistance R2
It is supplied to one end of a bridge circuit composed of R3, R4, R5 and the temperature sensor 13. The bridge circuit includes a reference voltage generation circuit and a temperature detection circuit.

The resistors R4 and R5 of the bridge circuit are
A reference voltage is generated at point B by resistance division. An output voltage representing temperature information is generated at the resistors R2 and R3 of the bridge circuit and the point A of the temperature sensor 13.

The point A of the bridge circuit is the comparator 14
Is connected to the negative input terminal, and point B is connected to the positive input terminal.

Next, the operation of this embodiment will be described.

A Zener current is supplied from the power supply voltage by the resistor R1 and a required constant voltage is generated by the Zener diode D. The constant voltage created by Zener diode D is
A bias current is supplied to the temperature sensor 13 via resistors R2 and R3 shown in the figure. Further, a reference voltage is created by dividing the resistors R4 and R5.

At the point A of the bridge circuit, the temperature sensor 13
The output voltage representing the temperature information of the
-Is supplied to the input terminal. On the other hand, the reference voltage created at the point B is supplied to the + input terminal of the comparator 14.

The comparator 14 compares the temperature sensor output voltage and the reference voltage and supplies the result to the control switch circuit and the heater drive circuit 15.

According to the temperature control device of this embodiment, when the power supply voltage changes, both the reference voltage generating circuit and the temperature detection circuit are supplied from the same voltage source. Therefore, the fluctuation of the control temperature can be reduced.

As an example, a specific numerical value is substituted for the calculation. When the values of the resistors R2, R3, R4 and R5, the value of the Zener voltage Vz of the Zener diode D, and the resistance value THR of the temperature sensor 13 are as follows: resistance R2: 3.01 kΩ resistance R3: 619Ω resistance R4: 3.01 kΩ Resistance R5: 1.12 kΩ Zener diode D: Vz = 8.4 V Temperature sensor 13: THR = 500 Ω (25 ° C.) In the temperature control device of FIG. 2, the heater is turned on at 25 ° C.
It is a circuit that does.

When the temperature sensor output voltage at point A is calculated,

[0018]

[Equation 1]

When the reference voltage at point B is calculated,

[0020]

[Equation 2]

[0021]

When the power supply voltage fluctuates due to some factor and the voltage Vz fluctuates by ΔV, the voltage at the point B changes by 2.28 × ΔV / Vz [V]. On the other hand, since the voltage at the point A is 2.28 × ΔV / Vz [V] when the temperature sensor resistance value THR is 500Ω, the temperature at which the heater is turned ON is also changed when the power supply voltage fluctuates. You can see that it does not change.

Further, since it does not have an independent constant current circuit or reference voltage generating circuit as in the conventional case, the total power consumption can be reduced.

[0024]

As described in detail above, according to the temperature control device of the present invention, there is an effect that the temperature control can be operated with low power consumption and high accuracy, and the temperature control of the observation equipment and the like can be performed with high accuracy. If it is used in equipment that requires, low power consumption,
There are advantages such as high accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a temperature control device of the present invention.

FIG. 2 is a circuit diagram of an embodiment of the present invention.

FIG. 3 is a block diagram showing a conventional temperature control device.

[Explanation of symbols]

 11 constant voltage generation circuit 12 reference voltage generation circuit 13 temperature sensor 14 comparator 15 control switch circuit and heater drive circuit

Claims (3)

[Claims] 1. A temperature control device having a temperature sensor detecting means, a reference voltage generating means, and a comparator for comparing an output voltage of the temperature sensor with the reference voltage, to detect the temperature. A temperature control device characterized in that the means and the means for generating the reference voltage are configured by one circuit. 2. The temperature control device according to claim 1, wherein the one circuit is a bridge circuit connected to a power supply voltage. 3. The temperature according to claim 2, wherein the bridge circuit is composed of a dividing circuit including a resistor for generating the reference voltage and a circuit including a resistor and a temperature sensor for generating the output voltage. Control device.