JPH08307160A - Temperature compensation circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] To compensate for characteristic changes due to temperature in circuits that include semiconductor elements. [Structure] The circuit 11 includes a semiconductor element, and changes in characteristics due to temperature, causing an error in the output of the operational amplifier 12. Therefore, a series connection circuit of two thermistors 13 and 14 is used for one of the voltage dividing resistors that output the control voltage 17 for temperature compensation, and the divided control voltage 17 is taken out between the thermistors 13 and 14. The control voltage 17 is generated by the partial pressure of the thermistors 13 and 14 and the fixed resistor 18 whose resistance changes with temperature, and the control voltage 17 increases as the temperature rises. Further, the two thermistors 13 and 14 are adjusted by the mutual change in the error associated with the resistance temperature characteristic, and the control voltage 17
Responds to temperature changes with high accuracy. Then, by applying the control voltage 17 to the operational amplifier 12 as a reference voltage, a temperature-compensated amplified output can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature compensating circuit using a temperature detecting element.

[0002]

2. Description of the Related Art Conventionally, temperature compensation of a circuit using a semiconductor element is performed by using one temperature detecting element as shown in FIG. 3 or FIG. When the characteristics of the semiconductor element circuits 31, 41 change with temperature, the voltage dividing resistor 33 for outputting the control voltage to the temperature detecting element 32 of FIG. 3 or the temperature detecting element 42 of FIG.
The temperature characteristic of the semiconductor element circuits 31 and 41 is corrected by detecting the ambient temperature of the temperature detecting element. If the temperature detecting element is a negative characteristic thermistor, the resistance value of the thermistor is expressed by the equation 1.

[0003]

[Equation 1]

R ₀ is the resistance value at the ambient temperature T ₀ , and R is the resistance value at the ambient temperature T. From the equation (1), there is an exponential relationship between the ambient temperature and the resistance value of the thermistor.

[0005]

However, in the temperature compensating circuit using one thermistor as shown in FIG. 3 or FIG. 4, the temperature characteristic of the compensating circuit can only be approximated to some extent.

That is, in the circuit of FIG. 3, the resistance of the thermistor 32 changes in response to the temperature rise, and the control voltage due to the voltage division between the thermistor 32 and the fixed resistor 33 increases, and in the circuit of FIG. 4, the thermistor 42. As a result, the control voltage due to the voltage division with the fixed resistor 43 decreases in response to the temperature rise,
The thermistor generally has an exponential curve in the resistance temperature characteristic, and has a drawback of causing an unacceptable error in the operating temperature range.

An object of the present invention is to provide a temperature compensation circuit that solves the above drawbacks.

[0008]

The above object is to provide a temperature detecting element having a resistance temperature characteristic of a negative or positive characteristic corresponding to an ambient temperature to one of the voltage dividing resistors for outputting a control voltage for temperature compensation. Provide at least two circuits connected in series,
This is achieved by providing a circuit for extracting the control voltage from between the temperature detecting elements forming the series circuit.

[0009]

With the above means, when the temperature rises due to the resistance-temperature characteristic of one of the temperature detecting elements forming the series circuit, the divided voltage increases, and depending on the resistance-temperature characteristic of the other temperature detecting element of the series circuit, the temperature rises. Then, the divided voltage decreases. Therefore, the output voltage between the two temperature detecting elements is finely adjusted by the mutual changes, and the error due to the exponential function characteristic of the resistance temperature characteristic of the temperature detecting element is corrected. Since the series circuit of the temperature detecting elements is provided in one of the voltage dividing resistors, the divided voltage that changes according to the change in ambient temperature can be output to the control voltage extracting circuit.

[0010]

EXAMPLES The present invention will be described below with reference to examples. FIG.
Is a circuit for comparing and amplifying the DC output voltage of the semiconductor element circuit 11 with the reference voltage by the operational amplifier 12 in the embodiment of the present invention.

Since the circuit 11 includes a semiconductor, the characteristic changes with temperature, and the output level changes with temperature. Therefore, it is necessary to offset the comparison reference voltage according to the temperature change. In this case, the comparison reference voltage uses the divided voltage output of the voltage dividing resistor. A circuit in which two thermistors 13 and 14 are connected in series is provided on one side of the voltage dividing resistor.
A control voltage 17 by dividing the voltage is taken out from between 3 and 14, and this is added to the operational amplifier 12 as a reference voltage for comparison.
Follow the temperature characteristics of 1.

In the thermistor 13 constituting the voltage dividing resistor circuit, the control voltage 17 to be output increases as the ambient temperature rises, and conversely in the thermistor 14, the control voltage 17 works so as to decrease as the temperature rises. If the resistance temperature characteristics of the two thermistors 13 and 14 are substantially equal to each other, the error associated with the exponential function characteristics is adjusted by the mutual change.

The control voltage 17 of the divided output by the thermistors 13 and 14 and the fixed resistor 18 whose resistance value changes according to the ambient temperature increases in accordance with the temperature increase.
The temperature change of the circuit 11 becomes highly accurate, and by using this as the comparison reference voltage of the operational amplifier 12, it is possible to follow the temperature change of the circuit 11 with high accuracy. Therefore, the output of the operational amplifier 12 is temperature-compensated. It is possible to generate a highly accurate amplified output similar to the case where there is no temperature change.

By connecting the resistors 15 and 16 in parallel or in series to the thermistors 13 and 14, it is possible to correct an error in the temperature characteristics of the thermistors 13 and 14 and at the same time to average the amount of resistance change. , The temperature characteristics of the circuit 11 can be made to follow more appropriately.

FIG. 2 shows another embodiment of the present invention in which a control voltage due to temperature change is directly applied to the semiconductor circuit 21 to compensate for changes in circuit characteristics due to temperature.

The control voltage 27 consists of a fixed voltage dividing resistor 22 and 2
It is a divided voltage of the thermistors 23 and 24, and is output between the thermistors 23 and 24. In the thermistor 23, the control voltage 27 output increases as the ambient temperature rises,
In the thermistor 24, the output control voltage 27 decreases as the ambient temperature rises. Therefore, the two thermistors 23 and 24 adjust the error associated with the exponential function characteristic of the resistance temperature characteristic.

The control voltage 27 of the divided voltage output by the thermistors 23 and 24 and the fixed resistor 22 whose resistance value changes depending on the ambient temperature decreases as the temperature rises, and corresponds to the temperature change with high accuracy. It will be what you did. By controlling the control voltage 27 in addition to the semiconductor circuit 21, it is possible to compensate the characteristic change due to the temperature change of the semiconductor element and perform follow-up control. As a result, the error in the normal operating temperature range is extremely small and can be tolerated.

Also in this embodiment, the parallel resistors 25 and 26 are connected to the thermistors 23 and 24, and the operation by this is the same as that of the embodiment of FIG.

In the circuit of FIG. 2, the detected control voltage 27 can be added to the semiconductor circuit 21 after being amplified or subjected to arbitrary adjustment control such as signal conversion.

In the above embodiments, the thermistor having the negative resistance temperature characteristic is used as the ambient temperature detecting element, but a detecting element having the positive resistance temperature characteristic may be used.

[0021]

As described above, by carrying out the present invention, temperature compensation of a circuit having a complicated temperature characteristic can be performed with high accuracy.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of an embodiment of the present invention.

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

FIG. 3 is a conventional circuit configuration diagram.

FIG. 4 is a conventional circuit configuration diagram.

[Explanation of symbols]

11 ... Semiconductor element circuit, 12 ... Operational amplifier, 13 ... Thermistor, 14 ... Thermistor, 15, 16 ... Resistor.

Claims (1)

[Claims] 1. In a circuit for temperature compensating an electric circuit using a semiconductor element, one of the voltage dividing resistors that outputs a control voltage for temperature compensation has a temperature that has a resistance-temperature characteristic in which the resistance changes in accordance with the ambient temperature. A temperature compensating circuit comprising a circuit in which at least two detection elements are connected in series, and an output circuit for extracting the control voltage from between the temperature detection elements forming the series circuit.