JP2976487B2 - Semiconductor device temperature characteristic correction device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature characteristic correction device for a semiconductor device that corrects a temperature characteristic of a signal output from a semiconductor device.

[Prior Art] In an apparatus using a semiconductor element such as a semiconductor pressure sensor, an output signal changes depending on an ambient temperature due to a temperature characteristic inherent to a semiconductor. Therefore, it is necessary to correct the temperature characteristic of the output signal. 2. Description of the Related Art An ambient temperature is detected using a temperature sensor such as a thermistor, and an output signal of a semiconductor device is corrected based on a result of the detection. In order to perform temperature compensation without using a temperature sensor, it has also been proposed to provide a semiconductor device with a resistor for temperature compensation, as described in, for example, Japanese Patent Publication No. 62-55629.

[Problems to be Solved by the Invention] When the temperature characteristics of the semiconductor device are corrected using a resistor as described above, a temperature sensor becomes unnecessary and the circuit configuration can be simplified. In the device, the mounting position of the temperature compensation resistor has to be changed according to the temperature characteristics of the semiconductor device, and there has been a problem that the adjustment work of the correction circuit becomes complicated.

Therefore, an object of the present invention is to provide a temperature characteristic correction device that can correct the temperature characteristics of a semiconductor device without using a temperature sensor, and that can easily perform the adjustment operation.

Means for Solving the Problems In order to achieve the above object, the present invention is directed to a temperature characteristic correction device for a semiconductor device whose output characteristic changes in accordance with the ambient temperature. Three terminals to which voltage signals having different temperature characteristics are applied; a terminal to which a voltage signal having the largest temperature characteristic is applied; and a terminal to which a voltage signal having the smallest temperature characteristic is applied. And two resistors connected in series between which the resistance value can be adjusted by trimming. Of the three terminals, a terminal to which a voltage signal having an intermediate temperature characteristic is applied; A fixed resistor that is connected between the connection points of the resistors and that is at least predetermined times larger than the resistance values of the two resistors; and that an output signal from the semiconductor device is corrected based on a current flowing through the fixed resistor. Supplement The temperature characteristic correction apparatus for a semiconductor device characterized by comprising: a means, are the subject matter.

[Operation and Effect of the Invention] As described above, in the temperature characteristic correction device of the present invention, the Y terminals are applied to three terminals to which voltage signals having different temperature characteristics are applied.
Connect the three connected resistors, and trim the two resistors connected between the terminal to which the voltage signal with the largest temperature characteristic is applied and the terminal to which the voltage signal with the smallest temperature characteristic is applied It is possible to make another resistor a fixed resistor that is larger than the resistance value of the two resistors by a predetermined factor, and correct the output signal from the semiconductor device based on the current flowing through the fixed resistor. I have.

Therefore, by trimming one of the two resistors that can be trimmed and adjusting the resistance value, the temperature characteristic of the current flowing through the fixed resistor can be arbitrarily set. By setting the temperature characteristic of the value in accordance with the temperature characteristic of the output signal from the semiconductor device, the output characteristic of the semiconductor device can be easily and accurately compensated for using the current value.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an electric circuit diagram showing a configuration of an entire pressure detecting device according to an embodiment to which the present invention is applied.

As shown in the figure, the pressure detection device of the present embodiment includes a bridge circuit 100 that converts pressure into an electric signal using a piezoresistance effect of a semiconductor, a constant current circuit 200 that supplies a constant current to the bridge circuit 100, A correction circuit 300 that generates a temperature correction signal for correcting the temperature characteristics of the pressure signal output from the bridge circuit 100, and by adding the pressure signal from the bridge circuit 100 and the temperature correction signal from the correction circuit 300 An adding circuit 400 for correcting the temperature characteristic of the pressure signal from the bridge circuit, and an amplifying circuit 50 for amplifying the temperature-corrected pressure signal output from the adding circuit 400 and outputting the amplified signal to the outside
0.

Here, first, the bridge circuit 100 is composed of four diffusion resistances Ra, Rb, Rc, and Rd constituting a semiconductor pressure sensor. The bridge circuit 100 also includes resistors R1 and R2 for correcting an unbalanced voltage generated at the output terminals b and c. Note that the relationship between the above resistors is Ra ≒ Rb ≒ Rc ≒ Rd, Ra << R
7, Ra << R8.

On the other hand, the constant current circuit 200 includes resistors R3, R4, R5 and an operational amplifier OP1, and the power supply voltage Vcc is controlled by the resistors R3, R4.
A constant current Io determined by the reference voltage Vo obtained by dividing the voltage and the resistance value of the resistor R5 is supplied from the positive terminal a of the bridge circuit 100.

Next, the addition circuit 400 outputs the output terminals b and c of the bridge circuit 100.
Are applied to both ends of a resistor R6 via a buffer constituted by operational amplifiers OP2 and OP3, and the voltage difference (Vb−Vc) is converted into a current IR6 flowing through the resistor R6. Thus, a pressure signal is generated. Further, a correction circuit 300 is connected to the addition circuit 400, and adds the pressure signal IR6 generated above and a temperature characteristic correction signal IR11 described later generated by the correction circuit 300, and amplifies via a transistor TR1. The output is output to the circuit 500.

Next, the amplifier circuit 500 includes the resistors R7 and R8 and the operational amplifier OP.
4 and a current (IR6 + I
A voltage signal corresponding to R11) is output as a detection signal.

Next, the correction circuit 300, which is a main part of the present invention, includes three resistors R9, R10, and R11 connected in Y. The resistors R9 and R10 can be adjusted in resistance value by trimming, and one end of the resistor R9 is connected to a bridge circuit 10.
0 is connected to the negative terminal c, and one end of the resistor R10 is grounded. The resistance values of the resistors R9 and R10 before trimming are set to the same value.

On the other hand, the resistor R11 is about 20 times the resistance value of the resistors R9 and R10 so that the temperature characteristic correction signal IR11 flowing through the resistor R11 becomes significantly smaller than the currents IR9 and IR10 flowing through the resistors R9 and R10. And one end thereof is connected to the Vb side terminal of the resistor R6 in the addition circuit 400.

In the pressure detection device of the present embodiment having the above-described configuration, assuming that a connection point voltage of each resistor in the correction circuit 300 is Vf, an output voltage VOUT representing a pressure detection result output from the amplification circuit 500 is expressed by the following equation. VOUT = R7 (Vb−Vc) / R9 + R7 (Vb−Vf) / R11 (1) The temperature characteristic ΔVOUT is expressed by the following equation (2).

ΔVOUT = R7 (ΔVb−ΔVc) / R9 + R7 (ΔVb−ΔVf) / R11 (2) Here, the first term on the right side of the equation (2) is a bridge circuit.
100, that is, the temperature characteristic of the semiconductor pressure sensor.
The term is a temperature characteristic in the correction circuit 300. Therefore, in order to make the temperature characteristic of the output voltage VOUT zero, the temperature characteristic of the correction circuit 300 can be used to correct the temperature characteristic of the bridge circuit 100.

By the way, in the second term on the right side of the above equation (2), if the voltage of the negative terminal d of the bridge circuit 100 is Vd and its temperature characteristic is ΔVd, then ΔVf can be described as follows: ΔVf = ΔVd · R10 / (R10 + R9) The temperature characteristic ΔVb of Vb is about half of the temperature characteristic of Vb (ΔVb = ΔVd / 2) because Vb is extracted from the middle of the bridge circuit 100.

Therefore, the second term on the right side of the above equation (2) is Can be described as follows. The resistor R depends on the temperature characteristic of the output voltage VOUT.
It can be seen that if the resistance value is adjusted by trimming 9 or R10, the temperature can be corrected well.

That is, in the present embodiment, since R9 is initially set to R10, as shown in the following table, the temperature characteristic ΔIR11 of the temperature characteristic correction current IR11 is zero before trimming, and if the resistor R9 is trimmed, R9 > R10, and the temperature characteristic ΔIR11 of the temperature characteristic correction current IR11 becomes positive. Conversely, if the resistor R10 is trimmed, R9 <R10, and the temperature characteristic ΔIR11 of the temperature characteristic correction current IR11 becomes negative.

Therefore, if the temperature characteristic ΔVOUT of the output voltage VOUT is positive, the resistor R10 is trimmed to make the temperature characteristic of the correction circuit 300, that is, ΔIR11 negative, and if the temperature characteristic ΔVOUT of the output voltage VOUT is negative, By trimming the resistor R9 to make the temperature characteristic on the correction circuit 300 side, that is, ΔIR11 positive, the output voltage VOUT can be temperature-compensated.

Adjustment of such temperature characteristics is performed first with resistors R9 and R10.
Before trimming, the temperature characteristic ΔVOUT of the output voltage VOUT is actually measured to determine the temperature characteristic of the bridge circuit 100. Based on this temperature characteristic, the connection point voltage Vf of each resistor in the correction circuit 300 is expressed by the following equation (3). Resistor R9 or R1 so that
0 may be trimmed (however, the following equation (3) can be obtained from the above equation (2) and Vf ≒ R10 / (R9 + R10) Vd).

As described above, in the pressure detecting device of the present embodiment, the correction circuit 300 is connected to the three Y-connected resistors R9 to R11.
And the negative terminal d of the bridge circuit 100 to which one end of the resistor R9 is applied with the voltage signal Vd having the largest temperature characteristic, and the other end of the resistor R10 having the minimum (0) temperature characteristic and 0 potential. A ground is connected to each of the resistor terminals of the adder circuit 400 to which the voltage signal Vb having an intermediate temperature characteristic is applied to one end of the resistor R11, and the resistors R9 and R10 can be adjusted in resistance value by trimming. . Therefore, one of the resistors R9 and R10 is trimmed to
The temperature characteristic of the temperature characteristic correction current IR11 flowing in 1 can be adjusted in both positive and negative directions, and the operation of adjusting the temperature characteristic correction current IR11 can be simplified.

In the above embodiment, the temperature characteristic of the output signal VOUT is corrected by adding the temperature characteristic correction current IR11 and the detection signal IR6 in the addition circuit 400. A circuit for correcting the output signal VOUT output from the amplifier circuit 500 based on the characteristic correction current IR11 is provided.
The UT may be corrected.

In the above embodiment, the temperature characteristic correction current IR11 is generated by using the voltage signals Vd and Vb having different temperature characteristics obtained by the bridge circuit 100 and the ground potential having no temperature characteristic. If such a voltage signal having a different temperature characteristic cannot be extracted from the semiconductor device, a voltage signal having a different temperature characteristic is generated by a forward voltage of a diode, a transistor, or the like, and the correction signal IR11 is generated using the voltage signal. You may make it.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram showing a configuration of an entire pressure detecting device according to an embodiment to which the present invention is applied. 100 bridge circuit, 200 constant current circuit 300 correction circuit, 400 addition circuit 500 amplifier circuit R9, R10, R11 resistors

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01L 9/00 G01L 1/00 G01R 17/12 G01D 3/04

Claims (1)

(57) [Claims] An apparatus for correcting a temperature characteristic of a semiconductor device, the output characteristic of which changes according to the ambient temperature, comprising: three terminals to which voltage signals having three different temperature characteristics including zero are applied; Two of the two terminals connected in series between the terminal to which the voltage signal with the largest temperature characteristic is applied and the terminal to which the voltage signal with the smallest temperature characteristic is applied, and whose resistance can be adjusted by trimming. And a resistor connected between a terminal to which a voltage signal having an intermediate temperature characteristic is applied and a connection point of the two resistors connected in series, and at least one of the two resistors A temperature characteristic correction device for a semiconductor device, comprising: a fixed resistor that is larger by a predetermined value than a resistance value; and a correction unit that corrects an output signal from the semiconductor device based on a current flowing through the fixed resistor. .