JPH02180409A - Temperature sensitive voltage generating circuit and temperature compensating element using same - Google Patents

Abstract

PURPOSE:To generate a sensitive voltage only in part of a temperature range by providing a switching circuit to connect a first transistor(TR), which is turned on at a temperature T1, and second TR, which is turned off at a temperature T2, and to operate in the temperature range of T1 to T2. CONSTITUTION:A thermister TR1 and a resistance R4 are set so as to be turned on at the temperature T1. A resistance R5 and a thermister RT2 are set so as to be turned off at the temperature T2. By turning on and off first and second TRs TR1 and TR2, switching circuits TR1 and TR2 are operated in the range from the temperature T1 to T2. Consequently in the partial area between the temperature T1 to T2, a sensitive voltage V2 is set so as to conform to the area, and in the area other than the partial area, a normal voltage V1 at a higher level than that of the sensitive voltage V2 is set. The values of the normal voltage V1 and the sensitive voltage V2 can freely be set by resistances R1, R2 and R3.

Description

Detailed Description of the Invention (Industrial Field of Application) The field of the present invention is a temperature-sensitive voltage generation circuit that detects the ambient temperature in a partial area and generates a sensitive voltage. The present invention relates to a temperature compensation element applied to a compensation voltage generation circuit for heavy compensation.

(Background of the Invention Wk) Temperature-compensated oscillators are widely used to compensate for frequency changes due to temperature characteristics, particularly those caused by crystal resonators. In Takumi, a temperature-compensated oscillator that is even more stable with respect to temperature is desired due to communication conditions that are becoming more severe year by year.

(Prior Art) FIG. 13 is a block diagram of a temperature compensation evaporator oscillator illustrating a conventional example of this type.

temperature? It consists of an Ifl compensation oscillation evaporator #S1 and a quality compensation circuit 2. The oscillation circuit 1 has a crystal resonator 3 as an oscillator.
7. Connect one end thereof to, for example, the oscillation transistor 5 on the circuit side 4. In combination with other circuit elements such as a capacitor f (not shown), a Colpis-Sot type circuit network is formed, for example. The crystal resonator 3 has a thickness-shear vibration state with a cutting angle of, for example, an AT cut. In addition, Vcc in the figure
is the power supply and vo is the output. Such an oscillation circuit has a temperature characteristic as shown in curve (a) of FIG. 14. In other words, it becomes a cubic curve with an inflection point near the room temperature of 25° C. mainly caused by the crystal resonator 3.

The temperature compensation circuit 2 includes a compensation voltage generation circuit 6 (hereinafter referred to as voltage generation circuit 6) and a voltage variable capacitance element 7. The voltage generating circuit 6 consists of a series/parallel network (not shown) of a temperature sensing element (for example, a thermistor 8) and a resistor 9 connected between the power supply Vcc and the ground potential.

Then, depending on the resistance value of the thermistor 8, a compensation voltage V11 responsive to the ambient temperature is obtained at the output terminal a. The voltage variable capacitance element 7 is, for example, a round voltage variable capacitance diode (hereinafter referred to as a variable capacitance diode), and the cathode side is connected to the voltage generating circuit 6.
The anode side of the output terminal a is grounded to the ground potential. Then, the connection point between the voltage generation circuit 6 and the variable diode 7 is connected to one end of the crystal resonator 3. And with something like this? By setting the lfl compensation voltage v,1 to a value that compensates for the two-grade characteristics of the oscillation circuit 1, a compensation temperature characteristic that satisfies the standard is obtained [curve (b) in Figure 14 above (problems with the prior art). However, the temperature compensated oscillator with the above configuration has the following problems that cannot be avoided in theory.
As is clear from the curve n (c) connecting the marks, if the standard is changed to the temperature range, for example, if T1 is 130 to 70°C and the frequency tolerance (hereinafter referred to as tolerance) is ±2 ppm, then
This compensation temperature characteristic satisfies the same standard. However, if the standard is set to allowable deviation ±jppm within the same temperature range ΔT1, the parts at -20° C. and 60° C. shown by the dotted line ① fall outside the standard.

Conventionally, in such a case, the value of each resistor 9 is corrected by recalculating based on the compensation temperature characteristics.

As a result, the voltage generating circuit 6 was newly manufactured and replaced, and the standard of tolerance + ippm was satisfied. However, for 17, -S, the value of the resistance is 1 to 2% even if it is a good one.
has an error of Furthermore, regarding the thermistor, strictly speaking, the error in resistance value and the B constant also change at each temperature. Therefore, even if the value of each resistor 9 is corrected, the compensation temperature characteristic according to the theoretical calculation is +0.5ppIT! This results in a certain degree of error. For this reason, in the conventional temperature compensated oscillator, even if the voltage generation circuit 6 is remanufactured, the tolerance is ±1p.
It has been theoretically difficult to reduce the value to p+n or less due to accuracy problems of each element. Then, the allowable deviation ΔfaF is ±
When the amount is 1 ppm or less, there is a problem in that the yield is extremely poor and the productivity is lowered.

(Points of Interest and Objectives of the Invention) The present invention is directed to
Focusing on the fact that temperature standards can be satisfied by further compensating only for the crystallinity region, we developed a temperature-sensitive voltage generating circuit that generates a sensitive voltage only in the above-mentioned partial humidity region, and a temperature-sensitive voltage generating circuit using this circuit. The purpose is to provide an In compensation element.

(Solution Means) The present invention provides a first toranosistor which turns on from OFF to ON when the first temperature-sensing element that is sensitive to ambient temperature is set with r rebias voltage, and a second temperature-sensing element that controls the bias voltage. A temperature-sensitive voltage generation circuit is formed from a switching circuit whose operating period is from temperature T to T2 by connecting it to a second transistor that turns from ON to OFF when temperature T2 is set. , and configuring a temperature compensation element from this is the solution. An embodiment of the present invention will be described below.

(Embodiment) FIG. 1 is a diagram of a temperature sensitive voltage generation circuit illustrating an embodiment of the present invention.

The compensation voltage generating circuit 10 consists of a switching circuit in which first and second transistors rrI and Tr2 are arranged in series with the voltage #iV, c (10C) on the collector side and the ground potential on the emitter side. In this switching circuit, the collector side of the transistor Trl (with a load resistance R, T
Resistors R2 and R are connected between the collector of rI and the emitter of Tr2.
8 are provided in series.

1) Let us assume that the connection point between resistors R2 and R3 is the output terminal. Further, a thermistor RT and a resistor R4 are provided for the bias dividing resistance of the transistor Tr1, and a resistor R3 and thermistor RT are provided for the same resistance of the transistor Tr2, respectively, on the pace side. Note that, as shown in FIG. 2, the humidity-voltage characteristics of the thermistors RT1 and RT decrease exponentially as the temperature changes from a low temperature to a high temperature. Then, as shown in Fig. 3, the thermistor RT
l and resistor R4 turn the transistor TR off at temperature T1.
``Figure (a)'' is set to turn on from F. Also, the resistor R6 and thermistor RT x are the transistor Tr
y is set to turn from ON to OFF when the temperature is 12 o'clock.

In such a case, the first and second transistors TrI
, Tr2 are turned ON and OFF, the switching time MP1 (T r, , T r i
"Fig. 3 (C)" assumes an operation period of 1. Therefore, as shown in FIG. 4, during the operation of the switching circuit, the output voltage between resistors R2 and R3 decreases due to the voltage drop across the load resistor R. That is, in a partial region between temperature T and T2, the responsive voltage v2 is set in response to this,
In areas other than some areas, the normal voltage V is higher than the sensitive voltage (2). Note that the values of the normal type (1) pressure and the sensitive voltage (2) can be freely set using resistors R1, R2, and R4.

Therefore, as shown in FIG. 5, if a variable capacitance diode 11 is connected to the output terminal of the temperature-sensitive voltage generating circuit 10 and a DC blocking capacitor 12 is provided [the same figure ((
11) J, "Figure (b)" in which a voltage variable capacitance element re can be obtained as the temperature compensation element 13 whose capacitance value changes only in a certain temperature range. 17. As shown in FIG.
(see Figure 3), the temperature T in the compensation temperature characteristic
, h', etc. By further compensating for the portion exceeding -1 p p m at T2, that portion can be brought within ±l ppm as shown in the p portion of curve (d) in FIG. 15.

(Q L, in this case, the sensitive voltage v2 as the compensation voltage is set to a value such that the frequency change is within ±lppm. Also, when the normal voltage ■□ is applied, the compensation 7 quality characteristics do not change, for example. It is necessary to make a small adjustment to the variable capacitor.In addition, with such a device, there is no need to remanufacture and replace the ζζ voltage generation circuit Is6 (temperature compensation circuit 2) as in the conventional temperature compensation oscillator. Since this temperature compensating element can be added to the wafer, the yield can be improved and productivity can be improved.

(Other Embodiments) FIG. 7 is a diagram of a temperature sensitive voltage generation circuit explaining another embodiment of the present invention.

The temperature sensitive voltage generating circuit 14 of the embodiment B is powered by a power source V6.
．． Transistor Tr3. (+DC) is on the collector side, earth potential is on the emitter and on side. It consists of a switching circuit with Tr4 arranged in parallel. In this switching circuit, a load resistor R6 is provided on the collector side of transistor Trs (Tra), and resistors R7 and R8 are connected in series between the collector and emitter (ground potential) of Tr3.

The connection point between the resistors R7 and R6 is defined as an output terminal C.

Also, a thermistor RT is used as a bias dividing resistance for the transistor Tr.

and resistor R9, and resistor RI0 for the same resistance of T r 4.
and thermistor RT4 are respectively provided on the base side.

The thermistor RT and resistor R8 are shown in FIG. 8(a).
As shown in , the transistor Tr3 is turned off at a temperature of 14
It is set to turn on from F.

Also, the resistor R1゜, thermistor RT, and the transistor T
"Fig. 8(b)" shows that r4 is set to turn from ON to OFF at temperature T3.

In such a device, the third and fourth transistors Tr3
, Tr4 is turned ON and OFF, and the period from temperature T3 to T4 is the operating period of switching cycle # (T rs, T ra) as shown in FIG. 8(C). Therefore, during the operation period of the switching circuit, Tr3, Tr4, @OF
Therefore, the output voltage between resistors R3 and R4 increases by W. In other words, as shown in FIG.
4, and a normal voltage (2) lower in level than the sensitive voltage v4 except in some areas.

Note that the values of the normal voltage v3 and the sensitive voltage V4 can be freely set using the resistors R1, R2, and R5, as described above.

Therefore, in this embodiment as well, if a variable area diode 15 is connected to the output terminal of the temperature sensitive voltage generating circuit 14 and a DC blocking capacitor 16 is provided as shown in FIG. a), 1, It is possible to obtain a voltage variable capacitance element as the temperature compensation element 17 whose capacitance value changes only in the - part temperature region [(h) in the same figure]. If this temperature compensator is connected to the temperature compensated oscillator described above as shown in FIG. can be kept within ±lppm as shown in the p portion of curve (d) in FIG. 13 above.

However, in this case as well, the sensitive voltage V4 as the compensation voltage is set to a value such that the frequency change is within ±1 ppm.

Furthermore, it is necessary to adjust the compensation temperature characteristics using, for example, a variable capacitor so that the compensation temperature characteristics do not change when the normal voltage (2) is applied. In addition, since there is no need to remanufacture and replace the voltage generation circuit 6 (temperature compensation circuit 2) as in the conventional case, the yield can be improved and productivity can be improved.

(Other Matters) In the above embodiment, a case was explained in which a portion of the conventional compensation temperature characteristic that deviates to the + side or - side is separately compensated.
Of course, as shown in FIG. 12, it is also possible to compensate for both the portions that deviate to the + and - sides. Basically, it is possible to compensate for the portion exceeding the standard regardless of the form of the temperature m-compensation characteristic. In addition, the conventional compensation temperature characteristic is based on voltage control.
Nonaka, for example, the so-called direct circuit consisting of series and parallel circuits of thermistors, capacitors, and resistors? This can be applied even if it is based on the IQ compensation method.

Further, the present invention additionally produces the following effects.

In other words, the temperature characteristics of the crystal resonator 3 are theoretically equal to room temperature 2.
It is a cubic curve with an inflection point near 5°C, but in reality, even if it is designed with the theoretical temperature characteristics as the target, the temperature characteristics will be distorted due to slight effects such as secondary vibrations and slight differences in cutting angles. come. Some of these crystal resonators cannot be used as crystal resonators for temperature-compensated oscillators because their temperature characteristics cannot be fully compensated for. However, if the present invention is applied, even if the temperature characteristics deviate somewhat from the theoretical values, the temperature characteristics can be partially compensated for and fully utilized, resulting in a significant economic advantage for the manufacturer.

Further, although the temperature sensitive voltage generation circuit has been described as a temperature compensation element of a temperature compensation oscillator, it can of course be applied as a sensor for detecting the temperature of a partial area.

(Effects of the Invention) The present invention provides a temperature-sensitive voltage generating circuit in which a bias voltage is set by a first temperature-sensing element that is sensitive to ambient temperature.
The bias voltage is set by the first transistor, which changes from OFF to ON, and the second temperature sensing element, and the voltage changes to O at temperature T3.
Since the switching circuit is connected to a second transistor that turns off from N to T2, and the switching circuit is activated when the temperature is T□ to T2, it generates a sensitive voltage only in a certain temperature range, making it particularly useful for temperature-compensated oscillators. It can be used as a compensation voltage, in which case the effect of improving productivity can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a diagram of a one-grade sensitive voltage generation circuit explaining one embodiment of the present invention, Fig. 2 is a temperature resistance characteristic diagram of a thermistor, and Fig. 3 (a), (b), and (c) are the same embodiment. FIG. 4 is a temperature-voltage characteristic diagram of the same embodiment. FIG. 5(a) is a diagram of a temperature compensation element using the same embodiment. (b) is a temperature range characteristic diagram of the same temperature compensation element, and FIG. 6 is a schematic configuration diagram of a quality compensation oscillator (using the same temperature compensation element). FIG. 7 is a diagram of a temperature-sensitive voltage generating circuit explaining another embodiment of the present invention, and FIGS. 8(a), (b), and (C) are switching diagrams explaining the operation of the temperature-sensitive voltage generating circuit of the same embodiment. The characteristic diagram, FIG. 9, is the temperature-voltage characteristic diagram of the same example, and FIG. 10 (a
) is the moisture content using the same example? Diagram of ltl compensator, 1st
Figure 0(b) is the temperature capacity characteristic diagram of the same temperature compensation element, No. 11.
The figure is a schematic configuration diagram of a temperature compensated oscillator using the same temperature compensation element. FIG. 12 is a schematic diagram of a temperature compensated oscillator illustrating another embodiment of the present invention. FIG. 13 is a schematic configuration diagram of a temperature compensated oscillator explaining a conventional example, 14y4 is a temperature characteristic diagram, and FIG. 15 is an enlarged diagram of the curve (a) in FIG. 14. 9th flash 10th leap (a) 11th flash 1st leap (b) 12th! ! 1

Claims (3)

[Claims] (1) Set the bias voltage using the first temperature sensing element whose resistance value changes in response to the ambient temperature, and turn it off at temperature T_1.
a first transistor that turns on at a temperature of T_2, and a second transistor that turns off from on at a temperature T_2 by setting a bias voltage using a second temperature sensing element whose resistance value changes in response to ambient temperature; 1. A temperature-sensitive voltage generating circuit, characterized in that one transistor and a second transistor form a switching circuit that operates during a temperature range from T_1 to T_2, and generates a sensitive voltage only during the operating period of the switching circuit. (2) The sensitive voltage is a compensation voltage applied to a voltage variable capacitance element connected to a crystal resonator of a temperature-compensated crystal oscillator to compensate for the frequency-temperature characteristics of the crystal oscillator. Temperature-sensitive voltage generation circuit described in . (3) A temperature compensation element, characterized in that a voltage variable capacitance element is connected to the output terminal of the temperature-sensitive voltage generation circuit according to claim 1, and is used for compensating the frequency-temperature characteristics of a crystal oscillator.