JPH08237036A - Temperature compensation circuit - Google Patents

Abstract

PURPOSE: To provide an optional temperature change voltage changed also linearly at an output terminal by adjusting minutely the rising voltage of a transistor(TR). CONSTITUTION: The circuit is provided with a 1st TR 5 whose base receives a 1st input voltage and whose emitter connects to one terminal of a 1st resistor 7, a 2nd TR 8 whose base receives a 2nd input voltage, whose emitter connects to a 2nd resistor 10 and whose collector connects to the other terminal of the 1st resistor 7, and an output terminal connecting to the other terminal of the 1st resistor. An optional temperature change voltage based on a rising voltage of the TRs is obtained by changing a ratio of the resistance of the 1st and 2nd resistors.

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 for an output voltage in a transistor circuit, and in particular, a change in the output voltage with respect to temperature change can be arbitrarily set and the change amount can be linearly changed. The present invention relates to a temperature compensation circuit.

[0002]

2. Description of the Related Art It is well known that the rising voltage Vbe of a transistor or a diode changes due to a change in ambient temperature. As the temperature rises, its rising voltage Vbe
Will fall. For example, in the circuit shown in FIG. 2, when a constant voltage X (voltage that does not change with temperature) is applied to the input terminal (1), the rising voltage Vbe of the transistor (3) is applied to the output terminal (2). Voltage (X + V
be) occurs.

A graph of the relationship between the voltage generated at the output terminal (2) and the temperature is shown by a solid line A in FIG. Since the rising voltage Vbe is lowered due to the temperature rise, the entire output voltage is lowered. It may be desired to change the curve of solid line A in FIG. That is, this is a case where an output voltage having a desired temperature change voltage is desired to be obtained at the output terminal (2). In such a case, it is possible by adjusting the number of transistors (diodes).

FIG. 4 shows such a circuit, in which a diode (4) is inserted. A voltage (X + 2Vb) obtained by adding the rising voltage of the diode (4) to the rising voltage Vbe of the transistor (3) is applied to the output terminal (2).
e) occurs. The amount of change of the voltage (X + 2Vbe) with respect to temperature is twice the curve of FIG. 3A, and the characteristic of FIG. 3B is obtained.

Therefore, an output voltage having a desired temperature change voltage can be obtained at the output terminal.

[0006]

However, by adding the diode (4) to the circuit of FIG. 2 as shown in FIG. 4,
The method of changing the temperature characteristic has a problem that the amount of change becomes discrete. That is, the amount of change was an integral multiple of the number of diodes, and a value in between could not be taken. Therefore, the output terminal (2) of FIG. 2 and FIG.
There has been a demand for a device that can obtain an output voltage that changes to a desired value depending on the temperature.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and a first transistor having a base to which a first input voltage is applied and an emitter to which one end of a first resistor is connected, and a base. A second transistor having a second input voltage applied to the emitter and a second resistor connected to the emitter and a collector connected to the other end of the first resistor; and an output terminal connected to the other end of the first resistor. It is characterized in that an arbitrary temperature change voltage based on the rising voltage of the transistor is obtained from the output terminal by changing the resistance ratio of the first and second resistors.

[0008]

According to the present invention, the first resistor is provided between the emitter of the first transistor and the collector of the second transistor, and the second resistor is provided at the emitter of the second transistor. Then, by changing the resistance ratio of the first and second resistors, the current flowing between the base and emitter of the first transistor and the second transistor changes, and the rising voltage can be finely adjusted, so that it also changes linearly. An arbitrary temperature change voltage that can be generated can be obtained from the output terminal.

[0009]

1 shows a temperature compensating circuit of the present invention, in which (5) is a base to which a first input voltage is applied from a reference power source (6) and one end of a first resistor (7) is connected to an emitter. The connected first transistor (8) has a base to which a second input voltage is applied from a reference power source (9), an emitter connected to a second resistor (10), and a collector connected to the other end of the first resistor (7). A second transistor (11) connected to is an output terminal connected to the other end of the first resistor (7).

Now referring to FIG. 1, the first transistor (5)
It is assumed that the first input voltage X is applied to the base of the reference power supply (6) and the second input voltage Y is applied to the base of the second transistor (8) from the reference power supply (9). Then, the resistance value of the first resistor (7) is set to R1, and the second resistor (1
The resistance value of 0) is R2, and the base-emitter voltage of the first and second transistors (5) and (8) is Vbe. If the current flowing through the second resistor (10) is I, the current I is

[0011]

[Equation 1]

[0012] Since the current flows through the first resistor (7), if the output voltage of the output terminal (11) is Vo,
The output voltage Vo is

[0013]

[Equation 2]

[0014] Therefore, by substituting equation (1) into equation (2), the output voltage Vo becomes

[0015]

(Equation 3)

[0016] As is clear from the equation (3), if the ratio of the resistor R1 and the resistor R2 in the third term of the equation (3) is changed, the coefficient of the base-emitter voltage Vbe is changed. When the voltage Vbe changes due to, the change corresponding to the ratio is exhibited. Therefore, FIG.
According to the circuit of, the resistance value R1 of the first resistor (7)
An arbitrary temperature change voltage can be obtained from the output terminal (11) by changing the ratio of the resistance (10) to the resistance value R2.

FIG. 5 shows another embodiment of FIG. 1 in which a PNP transistor is used as the first transistor (5) and a PNP transistor is also used as the second transistor (8). Components that operate in the same manner as those in FIG. by the way,
In the circuit of FIG. 1, if the ratio between the resistance R1 and the resistance R2 is changed, the DC voltage at the output terminal (11) changes, as is apparent from the equation (3). Therefore, the circuit of FIG. 6 is conceivable in which the temperature change voltage can be obtained from the output terminal (11) and the DC voltage of the output terminal (11) is prevented from changing.

In FIG. 6, (12) is a diode-connected transistor (1) with resistors (13) and (14).
A second input comprising a series circuit (18) of 5) to (17) (indicated by a diode symbol) and a transistor (19), including a voltage based on the resistance and a voltage having a variation based on the transistor. A voltage source that generates a voltage. The difference between FIG. 6 and FIG. 1 is that the temperature change voltage is applied to the base of the second transistor (8) from the terminal (20).

In FIG. 6, the same circuit elements as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Now, it is assumed that the voltage VCTL of the terminal (20) has a constant voltage Y and a temperature fluctuation voltage β due to the voltage source (12). Then, the output voltage Vo is calculated by the same calculation as the equations (1) to (3).

[0020]

[Equation 4]

[0021] Therefore, in equation (4), R1
= R2, the output voltage Vo is

[0022]

(Equation 5)

It becomes The output voltage Vo of the equation (5) can be a temperature change voltage without changing the DC voltage (X and Y) by changing the voltage β corresponding to the temperature fluctuation. Next, it will be described that the voltage β can be adjusted to a desired value by the voltage source (12). Voltage source (12)
The resistance value of the resistor (13) is R3, the resistance value of the resistor (14) is R4, and the transistors (15) to (17)
And the base-emitter voltage of the transistor (19) is Vbe. Then, the voltage VCTL of the terminal (20) is calculated by the same calculation as the formulas (1) to (3).

[0024]

(Equation 6)

[0025] Therefore, in equation (6), the first
And the second term are each divided by R3, the voltage VCTL of equation (6)
Is

[0026]

(Equation 7)

[0027] The first term in equation (7) is a constant voltage, and the second term is a voltage that changes with temperature. That is,
The first term of equation (7) is the voltage Y, and the second term is the voltage β. Therefore, the voltage β can be changed by changing the resistance ratio (R4 / R3) of the second term.
Therefore, according to the circuit of FIG. 6, a desired temperature change voltage can be obtained at the output terminal (11) without changing the DC voltage (X and Y) as much as possible.

The voltage obtained at the output terminal (11) of the circuit of FIGS. 1 and 6 can be used in various ways. For example, the output terminal (11) is connected to the external transistor circuit of the IC as the output terminal of the IC. In this case, since the temperature change voltage amount inside the IC and the temperature change voltage amount outside the IC are slightly different, the resistors R3 and R4 in the voltage source (12) may be adjusted to match the difference.

[0029]

As described above, according to the present invention, the first
By changing the resistance ratio of the second resistor and the second resistor, the current flowing between the base and emitter of the first transistor and the second transistor changes, and the rising voltage thereof can be finely adjusted, so that it can be changed linearly. The temperature change voltage of can be obtained from the output terminal.

Further, according to the present invention, since the constant voltage Y and the temperature fluctuation voltage β are applied to the base of the second transistor by the voltage source, the desired temperature can be maintained without changing the output DC voltage. A varying voltage can be obtained at the output terminal.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a temperature compensation circuit of the present invention.

FIG. 2 is a circuit diagram showing a conventional temperature compensation circuit.

FIG. 3 is a characteristic diagram for explaining the operation of FIG.

FIG. 4 is a circuit diagram showing a conventional temperature compensation circuit.

FIG. 5 is a circuit diagram showing another temperature compensation circuit of the present invention.

FIG. 6 is a circuit diagram showing another temperature compensation circuit of the present invention.

[Explanation of symbols]

 (5) First transistor (8) Second transistor (7) First resistance (10) Second resistance

Claims (2)

[Claims] 1. A first transistor having a base to which a first input voltage is applied and an emitter to which one end of a first resistor is connected, and a base to which a second input voltage is applied to which an emitter is connected to a second resistor and a collector. Includes a second transistor connected to the other end of the first resistor, and an output terminal connected to the other end of the first resistor,
A temperature compensating circuit, wherein an arbitrary temperature change voltage based on a rising voltage of a transistor is obtained from the output terminal by changing a resistance ratio of the first and second resistors. 2. A first transistor in which a first input voltage is applied to a base and one end of a first resistor is connected to an emitter, and a series circuit of a resistor and a diode-connected transistor, and a voltage based on the resistor, A voltage source for generating a second input voltage including a voltage having a variation based on the transistor, a second input voltage from the voltage source is applied to the base, a second resistor is connected to the emitter, and a collector is the collector. A second transistor connected to the other end of the first resistor; and an output terminal connected to the other end of the first resistor,
A temperature compensating circuit, wherein an arbitrary temperature change voltage based on a rising voltage of a transistor is obtained from the output terminal by changing a resistance value in the voltage source.