JPH1028016A - Piezoelectric reference oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric reference oscillator which can suppress useless power consumption at a temperature compensating circuit. SOLUTION: The supply timing of a power supply voltage to the power terminal 8 of an oscillation circuit 1 is shifted from that of the power supply voltage to the power terminal 9 of a temperature compensating circuit 2 by separating the terminals 8 and 9 from each other. In addition, the useless power consumption at the temperature compensating circuit 2 is suppressed so that the usable time of the battery of a portable telephone set, etc., can be prolonged by delaying the supply of the power supply voltage to the circuit 2 until the oscillation of the oscillation circuit 1 is stabilized to a certain degree after power supply is made to the circuit 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric reference oscillator used in a terminal of a TDMA type cellular telephone.

[0002]

2. Description of the Related Art FIG. 8 shows an example of a conventional piezoelectric reference oscillator. In FIG. 8, the piezoelectric reference oscillator includes an oscillation circuit 1 including a buffer amplifier circuit and a temperature compensation circuit 2. The oscillation circuit 1 and the temperature compensation circuit 2 are each connected to a power supply terminal 30, and are supplied with a power supply voltage. Power terminal 30
Is connected to a bypass capacitor 31. The oscillating circuit 1 includes transistors 3 and 4, a quartz oscillator 5 as a piezoelectric body, a varactor diode 6, and the like. The oscillation circuit 1 has a signal output terminal 7.

The oscillation circuit 1 is a Colpitts type oscillation circuit.
The transistor 3 is used for oscillation. The resonance circuit is composed of a crystal unit 5 and a varactor diode 6. The cathode of the varactor diode 6 is connected to the temperature compensation circuit 2 via a resistor.
Is supplied from the temperature compensation circuit 2. The transistor 4 is for a buffer amplifier of an output signal.

Next, the operation of the circuit will be described. Oscillation circuit 1
Oscillates at a frequency determined by a resonance circuit composed of the crystal oscillator 5, the varactor diode 6, the oscillation transistor, and the capacitance of the peripheral circuit. The resonance frequency of the crystal unit 5 is
Some fluctuations occur depending on the ambient temperature. Thus, the oscillation frequency of the oscillation circuit 1 also fluctuates. On the other hand, the thermistor included in the temperature compensation circuit 2 also has a characteristic that the resistance value changes depending on the ambient temperature. Therefore, the output voltage of the temperature compensation circuit 2 also varies depending on the ambient temperature. Since the output of the temperature compensating circuit 2 is connected to the cathode of the varactor diode 6, the capacitance of the varactor diode 6 changes due to a change in the output voltage of the temperature compensating circuit 2 due to a change in the ambient temperature. The oscillation frequency of the oscillation circuit 1 that includes in the resonance system fluctuates.

As described above, the oscillation frequency of the oscillation circuit 1 varies depending on the temperature characteristics of the crystal oscillator 5 and the temperature characteristics of the temperature compensation circuit 2. The temperature compensating circuit 2 is configured so that changes in the oscillation frequency caused by the temperature compensating circuit 2 cancel each other. Thus, the fluctuation of the oscillation frequency of the oscillation circuit 1 due to the ambient temperature is minimized. The oscillation output is from the collector of transistor 3.
The signal is output to the signal output terminal 7 via a buffer amplifier constituted by the transistor 4.

[0006]

In a cellular telephone system of the TDMA system, a time period during which a base station transmits (hereinafter, referred to as a time zone).
The time slot transmitted by the terminal differs from the time slot transmitted by the terminal, and the terminal receives only the time slot transmitted by the base station when the terminal waits. That is, the piezoelectric reference oscillator is operated only during that time period, and the supply of the power supply voltage to the piezoelectric reference oscillator is stopped during other time periods. Also, at the time of transmission of the terminal, the piezoelectric reference oscillator is operated only in the time slot allocated to the own terminal, and the supply of the power supply voltage to the piezoelectric reference oscillator is stopped in the time slot allocated to other terminals. Like that. Thus, the life of the internal battery of the terminal is extended by not operating the piezoelectric reference oscillator during the unnecessary time period.

Incidentally, the piezoelectric reference oscillator cannot instantaneously perform stable oscillation even when the supply of the power supply voltage is started, and requires a certain time until the frequency is stabilized. Therefore, the supply of the power supply voltage of the piezoelectric reference oscillator is started shortly before the time slot originally required for reception or transmission,
The piezoelectric reference oscillator is used in a stable manner until a required time slot comes.

However, since power is consumed even during the time until the piezoelectric reference oscillator is stabilized, there is a circuit that can reduce the power consumption of the terminal even if it is small in order to reduce the battery of the terminal and extend the life. is necessary.

An object of the present invention is to provide a piezoelectric reference oscillator that satisfies such requirements.

[0010]

To achieve the above object, a piezoelectric reference oscillator according to the present invention comprises at least a thermistor and a resistor, and a temperature compensating circuit for generating a DC voltage corresponding to an ambient temperature; In a piezoelectric reference oscillator including at least an oscillation circuit using a body element as a resonance element, a power supply terminal of the temperature compensation circuit and a power supply terminal of the oscillation circuit are separately provided.

Further, a piezoelectric reference oscillator according to the present invention comprises a temperature compensating circuit which comprises at least a thermistor and a resistor and generates a DC voltage corresponding to an ambient temperature, and an oscillation circuit which uses a piezoelectric element as a resonance element. In a piezoelectric reference oscillator including at least a first power switch for supplying a power supply voltage to the oscillation circuit, and a first power switch connected to the first power switch, the first power switch being connected to the temperature compensation circuit when the first power switch is ON. A first power switch for controlling the first power switch, the second power switch having a second power switch capable of selecting supply of a power voltage;
And a second terminal for controlling the second power switch.
Is characterized by having a control terminal of

Further, the piezoelectric reference oscillator of the present invention is connected to the first control terminal and the second control terminal, and supplies a power supply voltage to the oscillation circuit with a power supply voltage to the temperature compensation circuit. And a delay interlocking control circuit for performing control so as to delay the supply of the control signal.

Further, the piezoelectric reference oscillator of the present invention comprises at least a thermistor, a resistor and the like, a temperature compensation circuit for generating a DC voltage corresponding to the ambient temperature, and an oscillation circuit using the piezoelectric element as a resonance element. Wherein the power supply voltage to the temperature compensation circuit is supplied by a time delay circuit later than the power supply voltage to the oscillation circuit.

[0014]

FIG. 1 shows an embodiment of a piezoelectric reference oscillator according to the present invention. In the description of the present embodiment, the same or common parts as in the conventional example are denoted by the same reference numerals,
Detailed description is omitted. In FIG. 1, the piezoelectric reference oscillator includes an oscillation circuit 1 and a temperature compensation circuit 2. The oscillation circuit 1 and the temperature compensation circuit 2 have a power supply terminal 8 and a bypass capacitor 10 and a power supply terminal 9 and a bypass capacitor 11 independently of each other.

According to the configuration of the present embodiment, the power supply terminal 8 of the oscillation circuit 1 and the power supply terminal 9 of the temperature compensation circuit 2 are independent. Therefore, the power-on timing of the two circuits can be externally controlled. And a temperature compensation circuit 2
Is made up of a thermistor or a resistor that does not include a capacitor, so that it rises immediately when the power supply voltage is supplied, and starts a normal operation in a period sufficiently shorter than the rise time of the oscillation circuit 1. Although a bypass capacitor 11 is connected to the power supply terminal 9, the capacitance is sufficiently small and does not affect the rising speed of the temperature compensation circuit 2. On the other hand, when compared with the current consumption, the temperature compensation circuit 2
Is 40% of the total power consumption of the piezoelectric reference oscillator.
Account for about%. Therefore, as shown in FIG. 2A, the supply of the power supply voltage to the temperature compensation circuit 2 is controlled to be delayed from the supply of the power supply voltage to the oscillation circuit 1 by a time until the oscillation is stabilized. FIG. 2B shows a time change of the amplitude of the oscillation signal from the signal output terminal 7 at that time. As a result, it is possible to save power that is wasted in the temperature compensation circuit 2 during that time.

FIG. 3 shows another embodiment of the piezoelectric reference oscillator according to the present invention. Here, the same portions as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 3, the piezoelectric reference oscillator includes an oscillation circuit 1 and a power switch 13, and a temperature compensation circuit 2 and a power switch 14. The power switch 13 is connected to the power terminal 12 and controls supply of a power voltage to the oscillation circuit 1 and the power switch 14.
The power switch 14 is subordinate to the power switch 13 and controls supply of a power voltage to the temperature compensation circuit 2. That is, the supply of the power supply voltage to the temperature compensation circuit 2 can be turned ON / OFF by the power supply switch 14 only when the power supply switch 13 is ON. The power switches 13 and 14 have control terminals 15 and 16, respectively.
ON / OFF of the power switches 13 and 14 by the signal to
Control.

This circuit has terminals for controlling the supply of power supply voltage to the oscillation circuit 1 and the temperature compensation circuit 2.
Therefore, the supply of the power supply voltage to the temperature compensation circuit 2 can be made slower than the supply of the power supply voltage to the oscillation circuit 1 as in the circuit of FIG. Can be saved.

FIG. 4 shows still another embodiment of the piezoelectric reference oscillator according to the present invention. 4, the piezoelectric reference oscillator has a delay interlocking control circuit 17 connected to control terminals 15 and 16 in addition to the configuration of the circuit shown in FIG. An oscillation circuit 1, a temperature compensation circuit 2, a power switch 13,
The configuration and operation of 14 are exactly the same as those of the circuit of FIG. 3, and the same components are denoted by the same reference numerals and description of the circuit configuration or operation will be omitted.

In this circuit, control terminals 15 and 16 are controlled by a delay interlocking control circuit 17. Delay interlock control circuit 17
Then, the supply of the power supply voltage to the temperature compensation circuit 2 is automatically controlled so as to be slightly delayed from the supply of the power supply voltage to the oscillation circuit 1. As a result, it is possible to save power that is wastefully consumed in the temperature compensation circuit 2.

FIG. 5 shows still another embodiment of the piezoelectric reference oscillator of the present invention. In FIG. 5, a piezoelectric reference oscillator includes an oscillation circuit 1, a temperature compensation circuit 2, a voltage delay circuit 20,
It comprises a power supply terminal 18 and a bypass capacitor 19. The voltage delay circuit 20 includes a transistor 21 and a resistor 2
2, 24 and a capacitor 23. The collector of the transistor 21 is connected to the power supply terminal 18, and the emitter is connected to the ground through the resistor 24. The resistor 22 and the capacitor 23 are connected in series between the power supply terminal 18 and the ground, and are connected to the base of the transistor 21 from between them. The resistor 22 and the capacitor 23 form a delay circuit. The emitter of the transistor 21 is connected to the temperature compensation circuit 2.

FIG. 6A shows a time change of the voltage of the power supply terminal 18 and a time change of the base voltage and the emitter voltage of the transistor 21 (the power supply voltage of the temperature compensation circuit 2). When a voltage is applied to the power supply terminal 18, the power supply voltage is first supplied to the oscillation circuit 1 and the rising operation starts. The time change of the amplitude of the oscillation signal from the signal output terminal 7 at that time is 6
(B). On the other hand, the base voltage of the transistor 21 rises slowly under the influence of the delay circuit composed of the resistor 22 and the capacitor 23. Then, when the base voltage exceeds a certain level, the transistor 21 becomes conductive, and the power supply voltage is supplied to the temperature compensation circuit 2.

As described above, the supply of the power supply voltage to the temperature compensating circuit 2 can be stopped by the voltage delay circuit 20 until the oscillation circuit 1 rises to some extent, during which the temperature compensating circuit 2 wastes power. Power can be saved.

In FIG. 6, a combination of an NPN transistor and a CR delay circuit is used as the voltage delay circuit. However, another circuit configuration may be used as long as it has the same function. For example, as shown in FIG. Transistors can also be used.

In each of the above embodiments, a quartz oscillator is used as the piezoelectric body, but another piezoelectric element such as a piezoelectric ceramic element may be used instead of the quartz oscillator.

[0025]

According to the piezoelectric reference oscillator of the present invention, the supply of the power supply voltage to the temperature compensation circuit is delayed from the supply of the power supply voltage to the oscillation circuit so that the operation of the oscillation circuit becomes stable. , The power consumption in the temperature compensation circuit can be suppressed. As a result, the power efficiency of the piezoelectric reference oscillator can be increased, and the duration of the battery of the portable device can be increased or the weight can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a piezoelectric reference oscillator according to an embodiment of the present invention.

FIG. 2 is a diagram showing a change over time in the voltage of a power supply terminal and the amplitude of a signal at an output terminal when supply of a power supply voltage to a temperature compensation circuit is delayed from supply of a power supply voltage to an oscillation circuit using the circuit of FIG. FIG.

FIG. 3 is a circuit diagram showing a configuration of a piezoelectric reference oscillator according to another embodiment of the present invention.

FIG. 4 is a circuit diagram showing a configuration of a piezoelectric reference oscillator according to another embodiment of the present invention.

FIG. 5 is a circuit diagram showing a configuration of a piezoelectric reference oscillator according to another embodiment of the present invention.

FIG. 6 is a graph showing the time variation of the voltage of the power supply terminal and the amplitude of the signal of the output terminal when supply of the power supply voltage to the temperature compensation circuit is delayed from supply of the power supply voltage to the oscillation circuit using the circuit of FIG. FIG.

FIG. 7 is a circuit diagram showing a configuration of a piezoelectric reference oscillator according to another embodiment of the present invention.

FIG. 8 is a circuit diagram showing a configuration of a conventional piezoelectric reference oscillator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Oscillation circuit 2 ... Temperature compensation circuit 3, 4 ... Transistor 5 ... Crystal oscillator 6 ... Varactor diode 7 ... Signal output terminal 8, 9 ... Power supply terminal 10, 11 ... Bypass capacitor 100 ... Piezoelectric reference oscillator

Claims (4)

[Claims] 1. A piezoelectric reference oscillator comprising at least a temperature compensating circuit comprising at least a thermistor and a resistor and generating a DC voltage corresponding to an ambient temperature, and an oscillation circuit using a piezoelectric element as a resonance element. A piezoelectric reference oscillator characterized in that a power supply terminal of a temperature compensation circuit and a power supply terminal of the oscillation circuit are separately provided. 2. A piezoelectric reference oscillator comprising at least a temperature compensating circuit configured to generate a DC voltage corresponding to an ambient temperature and configured by at least a thermistor and a resistor, and an oscillation circuit using a piezoelectric element as a resonance element. A first power switch for supplying a power voltage to the oscillation circuit; and a second power switch connected to the first power switch, the power supply voltage being supplied to the temperature compensation circuit when the first power switch is turned on. A first control terminal for controlling the first power switch;
A piezoelectric reference oscillator having a second control terminal for controlling the second power switch. 3. A delay connected to the first control terminal and the second control terminal, the delay controlling the supply of the power supply voltage to the oscillation circuit to be delayed from the supply of the power supply voltage to the temperature compensation circuit. Having an interlock control circuit,
The piezoelectric reference oscillator according to claim 2. 4. A piezoelectric reference oscillator comprising at least a temperature compensating circuit configured by at least a thermistor and a resistor and generating a DC voltage corresponding to an ambient temperature, and an oscillation circuit using a piezoelectric element as a resonance element. The power supply voltage to the temperature compensation circuit by the time delay circuit,
A piezoelectric reference oscillator characterized in that it is supplied with a delay from a power supply voltage to the oscillation circuit.