JPS6181006A - Temperature compensating crystal oscillating circuit - Google Patents

Abstract

PURPOSE:To compensate the temperature in a wide high-temperature region by connecting a variable impedance element in parallel with a high-temperature region compensating capacitor and providing a bias circuit including a thermosensitive element which controls this variable impedance element. CONSTITUTION:A capacitor C5 which compensates the high-temperature region is connected in series to a crystal resonator 1. A diode D is connected as the variable impedance element in parallel with this capacitor C5 to constitute a high-temperature region compensating circuit 5. A bias circuit 4 consisting of a thermistor TH2 and a resistance R5 and resistances R3 and R4 as the bias circuit of an oscillating circuit are connected to the diode D, and the current flowed to the diode D is changed in accordance with resistance values of individual resistances and the thermistor. The impedance of the diode connected in parallel to the high-temperature region compensating capacitor is changed in proportion to the square of the flowed current. Thus, temperature compensation at >=65 deg.C is made easy and the control is possible up to 80 deg.C.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a temperature compensation circuit connected in series to a crystal resonator, and a temperature compensation circuit that compensates for high 1 = Fi and 7 = degrees. Related to compensated crystal oscillation circuits.

[Description of the prior art j Conventionally, it has been widely used as a stable signal source for crystal oscillators. Many crystal oscillators are AT-cut with T-time characteristics of a cubic curve, and have been used as ink oscillators for a long time. In order to temperature-compensate the characteristics of this cubic curve, either an indirect compensation circuit with a bias circuit including a 5-temperature element and a variable capacitance element such as a varicap, or a capacitor connected in series with the crystal resonator, and the capacitance Sensing T in series or parallel
= A face-to-face compensation circuit or the like is used to connect the elements.

However, even if the surface compensation circuit is compensated in the low Tz range, in the X4 range, especially above 70°C, the characteristics of the crystal oscillator body change greatly as 4Fl increases, so the ri
It was either atonement or a national disaster.

[Object and Structure of the Present Invention] The object of the present invention is to eliminate the above-mentioned drawbacks and provide an ink oscillator that is stable even in a high temperature range. In an oscillation circuit using a resonator, an FS thermosensor is connected in series to a high-temperature compensation capacitor or a crystal resonator, and a variable impedance element is connected in parallel with the high-temperature compensation capacitor to control the variable impedance element. This is a temperature compensated crystal oscillator circuit provided with an 11-earth circuit including elements.

[Explanation of Examples FIG. 1 is a circuit diagram showing an embodiment of the present invention.

1 is a crystal oscillator, which includes a transformer, a star TR, a resistor R1,
R2 and R3, R4 and capacitor CI, C2 and C3,
It is connected to the oscillation circuit 2 consisting of C4. Note that terminal A
is connected to ground, terminal B is connected to the output, and terminal C is connected to the power supply.

A low f=range circuit 3 for compensating for the low temperature range is connected in series to the crystal oscillator l. The low temperature range circuit 3 includes a temperature sensing element THI and a resistor R6 in parallel with the capacitor C7.
Connected to capacitor C6. In addition, VC Nibi C7
is a capacitor for finely adjusting the frequency. In addition, the crystal oscillator 1 has a capacitor C for compensating for the high temperature range.
5 are connected in series. A diode D is installed as a variable impedance element in the capacitor C5 that compensates for the high temperature range.
are connected in parallel to form a high temperature range compensation circuit 5.

The diode D is connected to a bias circuit 4 consisting of a thermistor TH2 and a resistor 4, and resistors R3 and R4, which are the bias circuit of the oscillation circuit. Change. Due to the potential difference between 2 points As a result, the impedance of the diode D changes, and the apparent capacitance M of the capacitor C5 connected in parallel changes. For example, as the temperature rises, the resistance of the thermistor TH2 increases, and the current flowing through the tie auto DI decreases. Then, the impedance of the diode D becomes larger, and the capacitance of the capacitor C5 becomes larger in appearance, so that the oscillation frequency can be lowered.

Here, the relationship between Gouioto's impedance and the TL flow is expressed as follows: ]2=-kl'' Here, 2 is the impedance of diode D, k is a constant, and 1 is the current flowing through diode D.

In this way, the impedance of the diode connected in parallel to the MK capacitor in the high temperature range or the flowing current rfLl changes depending on the current. In conventional circuits, compensation begins to take effect around 40 to 50 degrees Celsius, which does not require much compensation, and at temperatures above 65 degrees Celsius, it becomes dependent on the customization of the water and the 21 vibrator itself. However, in the present invention, the compensation effect does not appear unless the temperature is above 50°C, but with the circuit of the present invention, the compensation effect can be achieved at temperatures above 65°C, which cannot be achieved conventionally. irA has become easier. And even at 80℃, it is less than ±2oo-
It has become possible.

Note that in this embodiment, the compensation control circuit is stopped and the thermistor T)
! 2 is inserted between the power supply and the diode 9, but the same effect can be obtained even if the polarity of the diode D is reversed and the thermistor TH3 is connected between the diode D and the ground between the diode D and the ground, as shown in FIG.

FIG. 3 shows frequency-temperature characteristics in which the characteristics of the crystal resonator itself are represented by dotted lines, and the characteristics of a conventional temperature-compensated oscillator are represented by solid lines. The vertical axis is frequency change, and the horizontal axis is temperature. Here, the conventional 1g degree hff water compensated oscillator has a high l1ii
Due to the characteristics of the crystal oscillator itself, temperature fluctuations are not effective in this area.

FIG. 4 shows the frequency variation width 11 of a temperature 1IIi water compensated oscillator according to the invention. The dotted line is the characteristic of the Mizushina Shigetsu III Noko 1), and the actual line is the characteristic of the temperature compensated crystal oscillator according to the present invention. The present invention has made it possible to capture temperature over a wide range, which was not possible in the past.

[Effect 1 of the present invention Conventionally, in the high temperature range (
65~70℃) and the force that could not be compensated for by temperature.
Since the impedance of the variable impedance element connected in parallel to the high temperature oil injection capacitor of the present invention is controlled by the bias circuit including the element, M
It became possible to get used to it. In this way, it is possible to compensate for temperature in a wide range of high temperatures, and it has the advantage of being 80% less expensive and easier to adjust than conventional compensation methods.

In the present invention, as a variable impedance element,
Although a diode is used as an example, it is not limited to a diode, and may be a variable innovation element such as a transistor.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing another embodiment of the present invention, and FIG. 2 is a circuit diagram showing another embodiment of the present invention. 3 shows the frequency temperature characteristic 11 due to the crystal oscillator itself and the conventional temperature +X ink oscillator circuit, and FIG. 1... Ink vibrator, 2... Oscillation circuit, 3... Variable impedance element, 4...
...Bias circuit, C5...High temperature compensation capacitor Patent applicant Kinshichiki Co., Ltd.
Toshin 11 Masaru (self-motivated) Kuchi 8wa October 11, 1959 Commissioner of the Japan Patent Office Mr. Shiga Kan Teen 2 Name of the invention Temperature 1i1i1X Water quality oscillation circuit 3, person making the correction Number 201 TL story number foe) 489-231
Column 5 for Detailed Description of the Invention in the Specification 5 Contents of the Amendment (1) 1 Thick (Y) in the 7th line of the 4th page of the specification is corrected to ``Small.'' (2) Specification No. Page 4, line 8, “There are few, certain things, (
3. On page 4 of the specification, in the 7th loaf, it says 0 is large.
“Small,” I correct.

Claims (1)

[Claims] In an oscillation circuit using a crystal resonator having cubic curve characteristics, a high temperature range compensation capacitor is connected in series with the crystal resonator, a variable impedance element is connected in parallel with the high temperature range compensation capacitor, and the variable impedance element is connected in parallel with the high temperature range compensation capacitor. A temperature-compensated crystal oscillator circuit comprising a bias circuit including a temperature-sensitive element for controlling an impedance element.