JPH0247616Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a temperature compensation signal generation circuit that is used to compensate for characteristic fluctuations due to temperature fluctuations in various electronic devices, for example, and generates a temperature compensation signal in response to temperature fluctuations.

BACKGROUND ART Conventionally, a temperature-sensitive resistance element with a negative temperature coefficient has been generally used for so-called temperature compensation, which compensates for variations in output depending on temperature in electronic devices and the like. It has also been proposed to perform temperature compensation by utilizing the fact that the forward voltage of a junction diode changes depending on the temperature. In any case, these elements have only been directly connected to the target circuit to perform monotonically increasing or decreasing temperature compensation.

In conventional devices, it is generally difficult to create a linear function for temperature, and generating a linear function signal requires a complicated circuit that is difficult to design.
Furthermore, it is generally difficult to generate temperature compensation signals with various characteristics using one circuit.

The purpose of this invention is to be able to generate temperature compensation signals of various polygonal functions relatively easily, and to achieve generality that can be applied to electronic equipment etc. that require temperature compensation of various characteristics. An object of the present invention is to provide a temperature-compensated signal generation circuit.

This idea takes advantage of the fact that the forward voltage of a diode changes with temperature, amplifies this forward voltage with a variable gain inverting amplifier, and further amplifies the output of the variable gain inverting amplifier with another inverting amplifier. . The outputs of the variable gain inverting amplifier and the other inverting amplifier are added by an adder circuit to generate a temperature compensation signal. First and second switches are provided to allow the addition ratio to be varied and to apply the outputs of the inverting amplifiers to the adder circuit selectively or simultaneously. A rectifying element is connected in parallel to each feedback circuit of the variable inverting amplifier and the other inverting amplifier so as to be detachable.

Next, an embodiment of the temperature compensation signal generating circuit according to this invention will be described with reference to the drawings. In FIG. 1, a temperature sensing section 10 is provided. Temperature detection section 10
In this example, three junction diodes 11, 12,
13 are connected in series, one end of which is connected through a resistor 14 to a power supply terminal 15 to which a DC voltage of, for example, 15V is applied, and the other end is grounded to supply forward current to the diodes 11 to 13. The forward voltages of the diodes 11 to 13 change in response to changes in ambient temperature, thus forming the temperature detection section 10.

The output of this temperature sensing section 10 is supplied to a first inverting amplifier 16 whose gain can be changed.
That is, the connection point between the diode 11 and the resistor 14 is connected to the inverting input side of the operational amplifier 18 through the input resistor 17, and the variable resistor 19 is connected between the output side and the inverting input side of the operational amplifier 18. By adjusting the resistance value of this variable resistor 19,
The gain of inverting amplifier 16 can be adjusted.
The resistance value of the resistor 17 may be changed. A rectifying element 21 is removably connected in parallel to the feedback circuit of the inverting amplifier 16, that is, the variable resistor 19.

A variable bias voltage is applied to this inverting amplifier 16 so that a reference voltage can be set. That is, a terminal 22 to which a reference voltage is applied is grounded through a series circuit of a resistor 23 and a variable resistor 24, and a connection point between the resistor 23 and variable resistor 24 is connected to the non-inverting input side of the operational amplifier 18. By adjusting the resistance value of this variable resistor 24, the reference temperature is set.
For example, the bias voltage applied to the non-inverting input side of the operational amplifier 18 can be adjusted so that the output of the operational amplifier 18 at room temperature becomes a predetermined voltage. These resistor 23, variable resistor 24, and means for applying voltage thereto constitute reference setting means 25.

The output of the first inverting amplifier 16 is transmitted to the second inverting amplifier 2.
6. That is, the output side of the operational amplifier 18 is connected to the inverting input side of the operational amplifier 28 through the resistor 27, and the non-inverting input side of the operational amplifier 28 is grounded through the resistor 29, and between the output side and the inverting input side. A feedback resistor 31 is connected to. A rectifying element 32 is detachably connected in parallel to the feedback circuit of the second inverting amplifier 26, in this example a resistor 31.

Each output side of the inverting amplifiers 16 and 26 is connected to the input side of a summing circuit 35 through switches 33 and 34, respectively. The adder circuit 35 is capable of changing the addition ratio of the two signals to be added, and the switches 33 and 34 are connected to the adder circuit 3.
5 and is connected to the inverting input side of an operational amplifier 38 through variable resistors 36 and 37, respectively. The non-inverting input side of the operational amplifier 38 is connected to a resistor 39.
A feedback resistor 41 is connected between the output side and the inverting input side. This addition circuit 35
The output terminal 41 of is used as an output terminal of the temperature compensation signal generating circuit according to this invention.

According to this configuration, it is possible to generate a temperature compensation signal having various characteristics, especially a linear function. That is, the junction diodes 11 to 13 are assumed to have the same characteristics, for example, their forward voltage is about 0.5V, and the change in forward voltage with respect to temperature change of the junction diode is about -2.5mV/°C, Therefore, in this case, the diodes 11-1
3 in series, the forward voltage changes by approximately -7.5 mV/°C in response to temperature changes. A voltage that changes due to this temperature change is input from the temperature detection section 10 to the inverting amplifier 16. As mentioned above, the reference setting means 25 sets the output of the inverting amplifier 16 to a predetermined value, for example at room temperature.
The resistance value of the variable resistor 24 is adjusted so that the voltage becomes 1.5V. The gains of the inverting amplifiers 16 and 26 are G ₁ ,
G ₂ , the gain for the input from the switch 33 of the adder circuit 35 is G ₃₁ , and the gain for the input from the switch 34 is G ₃₂ .

To obtain a signal at the output terminal 41 in which the temperature compensation signal V ₀ decreases linearly as the temperature T increases, as shown in FIG. 2A, for example, turn on the switch 33.
Turn off the switch 34 and remove the rectifying element 21. In this way, the output voltage of the output terminal 41
For V ₀ , an output of V ₀ =−7.5G ₁ and G ₃₁ mV/°C can be obtained.

On the other hand, if you want the compensation signal V ₀ to increase linearly as the temperature T increases, as shown in FIG. 2B, switch 33 in FIG.
OFF, switch 34 is ON, and rectifier 2
Leave 1 and 32 removed. When the gain of the inverting amplifier 26 is 1, that is, the resistance values of the resistors 27 and 31 are equal, the temperature compensation signal V ₀ of the output terminal 41 is
V ₀ =7.5G ₁ , G ₃₂ mV/℃. In other words, since the inverting amplifier 26 is inserted here, the slope of the output fluctuation with respect to the temperature change, that is, the change in the forward voltage of the diodes 11 to 13, is the second.
This is the opposite of the case in FIG. A, and since the gain of the inverting amplifier 26 is set to 1, the slope can be changed by setting the variable resistor 19.

As shown in Figure 2C, in order to generate _{a compensation signal with linear characteristics such that the compensation signal V 0 decreases} linearly above a certain temperature and remains constant below a certain temperature, a switch is required. 33 is turned on, switch 34 is turned off, and the anode side of the rectifying element 21 is set as the inverting input side of the operational amplifier 18 as shown in the figure. When the input of the inverting amplifier 16 becomes larger than a certain level, that is, when the temperature T decreases and the forward voltage of the diodes 11 to 13 becomes larger than a certain level (at low temperature),
The rectifying element 21 becomes conductive, the output of the inverting amplifier 16 is clamped, and the output side of the operational amplifier 18 becomes
This becomes a constant value of 1.0V, and since the polarity of this is inverted by the adder circuit 35, a constant voltage of - is output. When the temperature T rises to a certain extent, that is, when it becomes high temperature, the rectifying element 21 becomes reverse biased and becomes the same as when it is removed, that is, the characteristics shown in Fig. 2A are obtained, and the output voltage is V ₀ = -7.5G. ₁ ,
G ₃₁ mV/℃, and the output voltage decreases linearly as the temperature increases.

Similarly, as shown in FIG. 2D, in order to generate a compensation signal that is constant on the high temperature side and linearly increases as the temperature T decreases on the low temperature side, the switch 33 in FIG. switch 34
ON, and the direction of the rectifying element 21 is opposite to that shown in Fig. 1, and its anode side is connected to the operational amplifier 1.
Just connect it to the output side of 8. In this case, on the low temperature side, the characteristics are similar to those in FIG.
1 conducts, the output voltage is clamped, and the temperature compensation signal V ₀ is held at a constant voltage. The clamp output in this case corresponds to the output of the inverting amplifier 16 being clamped to 2.0V.

As shown in FIG. 2E, in order to obtain a characteristic in which the compensation signal is constant on the low temperature side and increases as the temperature T rises on the high temperature side, the switch 33 is turned OFF.
Turn on the switch 34, remove the rectifying element 21, and connect the rectifying element 32 so that its anode side is connected to the operational amplifier 28.
Just connect it so that it is on the output side. In this case, the forward voltage of the diodes 11 to 13 increases on the low temperature side, and therefore the output voltage decreases on the output side of the inverting amplifier 16. When this decreases below a certain value, the rectifying element 32 becomes conductive and the inverting amplifier 2
The output of 6 is clamped to 0.5V by the rectifier 32. However, on the high temperature side, the rectifying element 32 is in a reverse bias state, which is similar to the state in which it is removed, resulting in the characteristic shown in FIG. 2B, which increases linearly as the temperature rises.

As shown in Figure 2F, on the high temperature side, the output is constant;
To obtain a characteristic in which the compensation signal decreases as the temperature decreases on the low temperature side, turn off the switch 33 and turn on the switch 34, remove the rectifying element 21, and turn off the rectifying element 3.
2 may be connected such that its cathode side becomes the output side of the operational amplifier 28. In this case, when the forward voltage of the diodes 11 to 13 drops to a certain level or more on the high temperature side, the output of the inverting amplifier 16 increases to a certain level or more, and the rectifying element 32 becomes conductive due to the output, and the inverting amplifier 26 The output of is clamped to −0.5V. However, when the temperature T becomes low and the forward voltage of the diodes 11 to 13 increases beyond a certain level, the output side of the inverting amplifier 16 decreases and the rectifying element 32 becomes reverse biased, which is removed. In other words, when the state shown in FIG. 2B is reached and the temperature T decreases, the output V ₀ monotonically decreases.

As shown in Figure 2G, the curved line characteristic increases monotonically as the temperature decreases below a certain temperature, and increases monotonically as the temperature increases on the high temperature side as well. Characteristics of A and Figure 2 E
It is only necessary to synthesize the characteristics of That is, switch 33,
34 are both turned on, and the gain in the adder circuit 35 is
Variable resistor 36 so that G ₃₂ is larger than G ₃₁
The resistance value of the variable resistor 37 may be made larger than the resistance value of the variable resistor 37. The addition circuit 35 is configured to be able to change the addition ratio in this manner. As can be seen from the characteristics in Figures 2A and 2E, the second
The characteristics shown in Figure E are constant on the low temperature side, so the characteristics shown in Figure 2 A come into play.
It has a characteristic that increases monotonically as the temperature decreases. On the high temperature side, Fig. 2A shows a monotonous decrease, Fig. 2E shows a monotonous increase, and the outputs are V ₀ = -7.5G ₁ , G ₃₁ +
7.5G ₁・G ₃₂ , and |G ₃₁ |<|G ₃₂ |, so it increases monotonically as a whole. ｜
If G ₃₁ | > | G ₃₂ |, it will decrease monotonically on the high temperature side, but the rate of decrease will be smaller than on the low temperature side.

As shown in Figure 2H, at a temperature lower than a certain temperature,
In order to make the compensation signal monotonically decrease as the temperature decreases, and increase monotonically as the temperature increases at high temperatures, the characteristics in Figure 2A and Figure 2F may be combined. . In this case, the characteristics shown in Figure 2 F are constant on the high temperature side, so they are dominated by the characteristics shown in Figure 2 A, and decrease monotonically as the temperature increases, and in this case also on the low temperature side. By making |G ₃₂ | larger than |G ₃₁ |, it can be assumed that the compensation signal decreases as the temperature decreases due to the characteristics of the sum of these figures 2A and 2F. . The output in this case is
V ₀ =−7.5G ₁ , G ₃₁ +7.5G ₁ , G ₃₂ .

As described above, according to the temperature compensation signal generation circuit according to the present invention, temperature compensation signals having various characteristics can be generated, and in particular, one having a broken line characteristic can be easily obtained. Generally, when the ambient temperature changes in electronic equipment, temperature drift occurs, and various performances and characteristics deviate depending on the temperature.This deviation increases when the temperature falls, decreases when the temperature rises, and It increases when the temperature increases, decreases when the temperature decreases, or is constant on the low temperature side and decreases on the high temperature side, constant on the high temperature side and increases on the low temperature side, or increases on the high temperature side and constant on the low temperature side, or It is constant on the high temperature side, decreases on the low temperature side, rises on the high temperature side, rises on the low temperature side,
It can be roughly divided into two trends: decreasing on the high temperature side and decreasing on the low temperature side.

When temperature-compensating such general characteristics using a temperature-sensitive resistance element, separate compensation circuits corresponding to these various characteristics must be prepared, and the general circuit can be simply adjusted and connected to each part. It was difficult to make it by. However, according to the temperature compensation signal generation circuit of this invention, various types of these characteristics can be easily controlled by selectively controlling the switches 33 and 34.
Furthermore, it can be easily obtained by disconnecting and connecting the rectifying elements 21 and 32 and switching their polarities, and adjusting the variable resistor 19 and the like. In other words, if the temperature compensation generation circuit shown in FIG. 1 is prepared, it becomes possible to compensate for the fluctuation characteristics of all general characteristics with respect to temperature.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing an example of a temperature compensation signal generating circuit according to this invention, and FIG. 2 is a characteristic diagram showing examples of various temperature compensation characteristics obtained by this invention. 11: Temperature detection section, 16, 26: Inverting amplifier,
25: Reference setting section, 35: Adding circuit, 41: Temperature compensation signal output terminal.

Claims (1)

[Scope of utility model registration request] a temperature detection section comprising a diode whose forward voltage changes in response to temperature changes and a current supply means for passing a forward current through the diode; and a first variable gain inverting amplifier to which the forward voltage drop of the diode is input. , a reference setting means for applying a bias voltage to the first inverting amplifier and setting the output voltage of the first inverting amplifier at a reference temperature, a second inverting amplifier for amplifying the output of the first inverting amplifier, and the first inverting amplifier. The output side of the amplifier and the output side of the second inverting amplifier are connected to the input side through a first switch and a second switch, respectively, and an addition circuit that can change the addition ratio and outputs a temperature compensated voltage; A temperature compensation signal generation circuit comprising: a first rectifying element detachably connected in parallel to a feedback circuit of an amplifier; and a second rectifying element detachably connected in parallel to a feedback circuit of the second inverting amplifier.