JP3272633B2 - Thermostat type piezoelectric oscillator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A piezoelectric oscillator is housed in a thermostat, and a temperature control circuit is controlled based on the detected temperatures of the temperature-sensitive elements provided inside and outside the thermostat to control the temperature of the heating element. The present invention relates to a piezoelectric oscillator that performs frequency control via a control voltage generation circuit from a temperature change detected by an element.

[0002]

2. Description of the Related Art Today's electronic devices are used in every situation and environment, from ordinary households to production factories, private cars to rockets, and the like. In these use environments, particularly in a temperature environment in which the temperature changes drastically, it becomes very difficult for the piezoelectric oscillator to compensate for the frequency temperature characteristic (hereinafter referred to as temperature characteristic) and supply a stable frequency.

[0003] In the first place, since the piezoelectric vibrator constituting the piezoelectric oscillator also has a temperature characteristic, it is difficult to compensate for the temperature characteristic of the piezoelectric oscillator even if the environmental temperature changes.

A temperature-compensated oscillator for improving the above-mentioned temperature characteristics has been widely used as a thermostatic oven type piezoelectric oscillator. A conventional thermostatic oven type piezoelectric oscillator is constructed by storing the piezoelectric oscillator, heating element, and thermosensitive element in the same thermostat, detecting the temperature in the thermostat with the thermosensitive element, and increasing / decreasing the heating element temperature via a temperature control circuit. The structure has a structure in which the operating environment temperature of the piezoelectric oscillator itself is kept constant and the temperature characteristics are remarkably improved.

FIG. 6 shows a block diagram of this embodiment. The piezoelectric oscillator, the heating element, and the temperature sensing element are housed in the same thermostat, and the temperature of the operating atmosphere (in the thermostat) of the piezoelectric oscillator is detected by the temperature sensing element. The temperature change detected by the temperature sensing element is replaced by a current signal for controlling the heating element by a temperature control circuit, and the driving current of the heating element is controlled so that the temperature in the constant temperature bath becomes constant. Therefore, in general, the set temperature in the thermostat is set at around 60 ° C. where the temperature change of the piezoelectric vibrator constituting the piezoelectric oscillator is smallest.

[0006]

However, as described in the above-mentioned prior art, the conventional thermostatic oven type piezoelectric oscillator manages the temperature in the thermostatic oven by a thermosensitive element in the thermostatic oven. Since the holding temperature of the oscillator is high and only the temperature inside the constant temperature bath can be controlled, it is difficult to avoid affecting the temperature inside the constant temperature bath with a change in the outside air temperature of the constant temperature bath.

Therefore, in order to maintain the temperature inside the constant temperature bath at a high temperature setting and to keep the temperature inside the constant temperature bath constant while absorbing the influence of the outside air temperature change, a very large current is required, and the constant temperature bath type piezoelectric oscillator itself is required. It is difficult to keep the power consumption low.

On the other hand, conventionally, a piezoelectric oscillator housed in a thermostat is caused by the temperature characteristics of a piezoelectric vibrator constituting the piezoelectric oscillator. It is very difficult to control the temperature characteristics more accurately, and there is a problem that it is very difficult to improve the temperature characteristics of the thermostatic oven type piezoelectric oscillator as a whole.

[0009]

[Means for Solving the Problems] In order to solve the above problems,
The present invention has a structure in which the temperature of both the inside and outside of the constant temperature chamber is detected, and the temperature difference between the inside and outside of the constant temperature chamber is detected by detecting the temperature inside and outside the constant temperature chamber, and the temperature is controlled based on the temperature information. By controlling the current of the heating element through the circuit, the temperature chamber temperature atmosphere in the state where the temperature chamber was kept constant in the past was changed to a slightly wider temperature chamber temperature atmosphere in the temperature chamber. The temperature is maintained.

In a slightly wider temperature chamber temperature atmosphere than before,
In order to maintain the temperature inside the thermostat, the piezoelectric oscillator itself controls the frequency of the piezoelectric oscillator via the control voltage generation circuit according to the temperature change detected by the temperature sensing element inside the thermostat or the temperature sensing element outside the thermostat. The combination of temperature control by a heating element that generates a control voltage and is controlled by temperature-sensitive elements inside and outside the thermostat and frequency control by the control voltage of a piezoelectric oscillator that is controlled by a temperature-sensitive element inside or outside the thermostat. The improvement of the current consumption was able to be realized.

Further, in the present invention, since the inside of the thermostat is maintained at a high temperature (+ 50 ° C. to + 70 ° C.) by the heating element, when the voltage of the piezoelectric oscillator is controlled by the thermosensitive element inside the thermostat, Since the range is narrow (+ 50 ° C. to + 70 ° C.), more accurate frequency control can be performed.

On the other hand, when the voltage of the piezoelectric oscillator is controlled by a temperature sensing element outside the thermostat, the outside air temperature range (−20 ° C. to
(+ 85 ° C.), which makes it possible to obtain smooth characteristics over the entire temperature characteristics.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In each drawing, the same reference numeral indicates the same object. FIG. 1 is a block diagram of the present invention according to claim 1. A heating element 2 for heating a voltage-controlled piezoelectric oscillator 3 in a thermostat 1, a thermosensor 4 in the thermostat 1, and a thermosensor 5 outside the thermostat to detect an outside air temperature.
A control voltage generation circuit 7 that controls the voltage of the voltage-controlled piezoelectric oscillator 3 based on temperature information of the outside-chamber temperature-sensitive element 5;
1 shows a thermostatic chamber type piezoelectric oscillator including a temperature control circuit 6 for controlling the heating element 2 based on temperature information of a temperature difference between the outside temperature sensing element 5 and the inside temperature sensing element 4.

A temperature control circuit 6 for controlling the heating element 2 includes:
It is controlled by temperature information of a temperature difference between the outside temperature sensing element 5 and the inside temperature sensing element 4, and a control voltage generation circuit 7 for controlling the voltage controlled piezoelectric oscillator 3 is based on the temperature information of the outside temperature sensing element 5. When controlled, it constitutes a thermostatic oven type piezoelectric oscillator.

FIG. 2 is a block diagram of the present invention according to claim 2. A heating element 2 for heating the voltage controlled piezoelectric oscillator 3 in the thermostat 1, and a thermosensitive element 4 in the thermostat provided in the thermostat 1
A control voltage generating circuit 7 for controlling the voltage of the voltage-controlled piezoelectric oscillator 3 based on temperature information of the temperature sensing element 4 inside the chamber, and a control voltage generating circuit 7 including an outside temperature sensing element 5 for detecting the outside air temperature outside the constant temperature chamber. 1 shows a thermostatic chamber type piezoelectric oscillator including a temperature control circuit 6 for controlling the heating element 2 based on temperature information of a temperature difference between the temperature element 5 and the temperature sensing element 4 in the chamber.

A temperature control circuit 6 for controlling the heating element 2
The temperature information of the temperature difference between the outside temperature sensing element 5 and the inside temperature sensing element 4 is controlled, and the control voltage generating circuit 7 for controlling the voltage controlled piezoelectric oscillator 3 is controlled by the temperature information of the temperature sensing element 4 inside the chamber. When controlled based on this, a thermostatic oven type piezoelectric oscillator is formed. In short, since the heating element 2 is controlled by the temperature information of the temperature difference between the outside temperature sensing element 5 and the inside temperature sensing element 4, the temperature difference inside and outside the constant temperature chamber can be reduced, and the heating element 2 is added to the heating element 2. Since the current value fluctuation can be reduced, the power consumption of the entire oscillator can be reduced as compared with the conventional case.

FIG. 5 is a graph showing a temperature change in a constant temperature bath and a temperature difference between the inside and outside of the constant temperature bath between the conventional example and the present invention. Conventionally, it has been attempted to obtain a stable oscillation frequency which is not affected by the temperature by keeping the temperature in the thermostatic chamber constant. Maintaining a constant temperature in the constant temperature bath requires an increase or decrease in the current flowing through the heating element 2 for keeping the temperature in the constant temperature bath due to a temperature change outside the constant temperature bath.

If the temperature (ambient temperature) outside the constant temperature bath is relatively high, the temperature of the constant temperature bath itself will be high.
Although a small current value is necessary, when the temperature outside the thermostat is extremely low, a large current value needs to be supplied to the heating element 2. Therefore, large power consumption is generated.

On the other hand, by detecting the temperature inside and outside the thermostat with each thermosensitive element as in the present invention, it is difficult to keep the temperature inside the thermostat constant, but the temperature difference between inside and outside the thermostat is difficult. Can be reduced. In short, power consumption to the heating element 2 for heating the inside of the thermostat can be reduced.

FIG. 3 shows a frequency change of the piezoelectric oscillator which changes according to the temperature in the thermostat of the present invention. In a conventional thermostatic oven type piezoelectric oscillator, the temperature is controlled so as to keep the temperature in the thermostatic oven constant, so that the frequency does not greatly change.
In the block diagrams of the present invention shown in FIG. 1 and FIG. 2, since the temperature in the thermostat fluctuates to some extent, the control voltage generating circuit 7 is provided to the piezoelectric oscillator housed in the thermostat by the temperature detected by the thermosensitive element. The voltage controlled piezoelectric oscillator 3 is used so that a voltage can be output from the device and the frequency can be controlled.

The control voltage generating circuit 7 outputs a voltage for controlling the voltage-controlled piezoelectric oscillator 3 based on the temperature from a temperature-sensitive element provided inside and outside the thermostat. When the voltage control from the control voltage generating circuit 7 is performed by the temperature sensing element in the thermostat in the thermostat as shown in FIG. 1, the temperature change in the thermostat is very small. No. 4 detects a narrow temperature range, and a device having a specification with high sensitivity in control accuracy can be used.

On the other hand, when the voltage control from the control voltage generation circuit 7 is performed by the temperature sensing element outside the thermostat as shown in FIG. 2, the temperature change outside the thermostat is large and the temperature sensing element outside the thermostat has a wide temperature range. It is also possible to use a device that has a specification that can detect a range and has sufficient control accuracy to cope with a slow temperature change.

As described above, whether the temperature detection location of the thermostatic chamber itself is set in the thermostatic chamber depending on the temperature sensitivity accuracy and specification of the thermosensitive element,
It is also a feature of the present invention that it is possible to select whether to perform detection from outside the thermostat.

[0024]

According to the present invention, the power consumption of an oscillator using a thermostat can be greatly reduced. Further, since the temperature sensing element for detecting the temperature inside / outside the thermostat and the place (inside / outside the thermostat) of the temperature sensing can be selected according to the specification of the temperature sensing element, the component parts management is simplified. I was able to.

[Brief description of the drawings]

FIG. 1 is a block diagram for controlling a control voltage generation circuit from a thermosensitive element outside a thermostatic chamber according to the present invention.

FIG. 2 is a block diagram for controlling a control voltage generation circuit from a thermosensitive element in a thermostat according to the present invention.

FIG. 3 is a characteristic diagram showing a control temperature range according to the present invention.

FIG. 4 is a characteristic diagram showing a control temperature in a conventional example.

FIG. 5 is a graph showing a temperature difference between inside and outside of a constant temperature bath of the present invention and a conventional example, and a temperature difference.

FIG. 6 is a block diagram showing an example of a conventional thermostatic oven type piezoelectric oscillator.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 constant temperature bath 2 heating element 3 voltage controlled piezoelectric oscillator 4 temperature sensor inside tank 5 temperature sensor outside tank 6 temperature control circuit 7 control voltage generation circuit

Claims (2)

(57) [Claims] 1. A heating element for heating a voltage-controlled piezoelectric oscillator in a thermostat, a thermosensor in the thermostat provided in the thermostat,
A temperature-sensing element outside the chamber that detects the outside air temperature outside the constant-temperature chamber,
A control voltage generating circuit that controls the voltage of the voltage-controlled piezoelectric oscillator based on the temperature information of the outside temperature sensing element, and the heating element based on temperature information of a temperature difference between the outside temperature sensing element and the inside temperature sensing element. A thermostatic chamber type piezoelectric oscillator consisting of a controlled temperature control circuit. 2. A heating element for heating a voltage-controlled piezoelectric oscillator in a thermostat, a thermosensor in the thermostat provided in the thermostat,
A temperature-sensing element outside the chamber that detects the outside air temperature outside the constant-temperature chamber,
A control voltage generating circuit for controlling the voltage of the voltage controlled piezoelectric oscillator based on the temperature information of the temperature sensing element in the chamber; and the heating element based on temperature information of a temperature difference between the temperature sensing element outside the chamber and the temperature sensing element in the chamber. Thermostat type piezoelectric oscillator consisting of a temperature control circuit that controls the temperature.