JP2540059B2 - Solid oscillator circuit - Google Patents

Description

TECHNICAL FIELD The present invention relates to a solid-state oscillator circuit, and more specifically,
When starting a remote control device microcomputer (hereinafter computer) in standby mode, it is possible to shorten the time until standby is released to start computer control, or to supply a stable clock signal to the computer side at a timing that can be ignored. And a ceramic oscillator circuit capable of

[Prior Art] Conventional remote control devices used for television receivers, component stereos, home appliances, etc. use 4-bit or 8-bit computers, and infrared rays are emitted under computer control. LE
D or the ultrasonic transducer is driven and the necessary data is transmitted to the receiver.

In this case, in order to reduce the power consumption of the remote control device, the computer or the like is operated or stopped in response to the button operation, and the oscillator circuit that generates the clock signal also responds to the button operation. It is being operated or stopped.

Generally, a ceramics oscillation circuit is used to generate a clock signal for the computer in this case. However, since the ceramics oscillator (or crystal oscillator) has a high Q, it has a certain level after the oscillation is started until it stabilizes. I need time.

Therefore, in order to prevent the oscillation waveform in the unstable region immediately after the start of oscillation from entering the computer side, a hardware timer circuit or the like is provided outside the computer,
Standby startup is in progress, which starts the computer after a certain period of time from the standby state.

FIG. 3 shows a timing chart of the standby activation in this case. In response to the end of the button operation, the standby request signal 10 is generated and the standby activation instruction 11 is issued at the trailing edge of the leading edge thereof. Then, the standby control signal 12 is generated at the leading edge thereof to put the inside of the computer in the standby state. At the same time, the clock control signal 13 is dropped at the leading edge of the standby control signal 12, and the clock oscillation circuit is stopped corresponding to the leading edge of the clock control signal 13, the generation of the clock signal 15 is stopped, and the standby state is entered. The device is in standby.

On the other hand, when the button is operated in the standby state, the clock signal oscillator circuit operates and the start signal 14 is generated at the same time. Therefore, after a certain period of time, the oscillation output of the clock oscillator circuit becomes stable and stable, and the clock signal is generated, but this is after a certain period of time when this start signal becomes the “H” level, and at this point the standby The state is released, first, the standby control signal 14 becomes "H", and then the clock control signal becomes "H" at this trailing edge, and the computer is started.

[Problems to be Solved] Here, the relatively long period until the start signal 15 becomes “H” is taken as the oscillation stabilization time of the clock signal generation circuit. If the oscillator circuit that generates 15 is a ceramic oscillator circuit,
It takes some time for the clock signal to oscillate in a stable manner. On the other hand, in the case of the CR oscillation circuit, it is not necessary to take the standby time much because the time until the oscillation stabilizes is relatively short. However, in the case of the CR oscillator circuit, the generated pulse of the clock signal itself does not have the accurate timing as in the ceramic oscillator circuit, and there is a risk that the computer may malfunction.

Therefore, if a ceramics oscillation circuit is used to obtain a stable clock signal, the computer is activated in standby by the timing control shown in FIG. 3, and a timer for counting a long time is required as an external circuit. In addition to the circuits on the computer side, many peripheral circuits such as a counter circuit are necessary externally. Therefore, the circuit becomes complicated and
Power consumption also increases. In addition, the time from pressing the operation button to activate the standby until the receiver responds is delayed accordingly.

The present invention solves the above-mentioned problems of the prior art, and can reduce the time to release the standby until the computer control is started or generate a stable clock signal at a timing that can be almost ignored. An object is to provide a ceramics oscillation circuit that can be generated.

[Means for Solving Problems] The configuration of the solid-state oscillator oscillator circuit according to the present invention for achieving such an object is such that the inversion voltage point on the upper side and the lower side on the lower side of the reference potential are either positive or negative. And a series circuit in which a resistor, a first capacitor, and a second capacitor are connected in this order from the output side to the input side of the hysteresis inversion amplifier circuit, And a solid oscillator connected in parallel to the second capacitor, the connection point side of the first capacitor and the second capacitor is set to the reference potential, and the capacitance component of the solid oscillator and the series circuit are used. The oscillation frequency is equal to or near the oscillation frequency of the solid oscillator.

[Operation] By thus setting the solid oscillator and the first and second capacitors of the CR oscillator circuit in parallel and setting the connection point (middle point) of the first and second capacitors to the reference potential , CR is set in the initial state when the oscillator circuit is powered on and started.
A clock signal is obtained by oscillation, and after a certain time, the transition from CR oscillation to oscillation by a solid-state oscillator is performed and a clock signal is obtained continuously.

As a result, a stable clock signal can be obtained in a relatively short time from the time of activation. Moreover, since the operation at the time of starting the computer or the like is often a specific program process that does not require an accurate clock signal, the computer side can be immediately started, and in a remote control device or the like, A device having a simple circuit and good response can be realized.

[Embodiment] An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment in which the solid oscillator oscillating circuit of the present invention is applied to a ceramics oscillating circuit, FIG. 2 (a) is an equivalent circuit in the case of the CR oscillating circuit, and FIG. ) Is an equivalent circuit in the case of the ceramics oscillation circuit.

In FIG. 1, reference numeral 1 denotes a hysteresis inverting amplifier circuit, which is composed of a hysteresis inverter 2 and a feedback resistor 2a.

Output side of hysteresis inverting amplifier circuit 1 and ground (GND)
A resistor 3 and a capacitor 4 are inserted in series between the input terminal of the hysteresis inverting amplifier circuit 1 and the ground, and a capacitor 5 is connected between the input side of the hysteresis inverting amplifier circuit 1 and the ground. The ceramic vibrator 6 is connected between the input terminal of the capacitor 5 and the input connection side terminal of the capacitor 5. Therefore,
The ceramic oscillator 6 includes a capacitor 4 and a capacitor 5.
Are connected in parallel with each other, and the connection point between the capacitors 4 and 5 is grounded.

In such a circuit, since the ceramic resonator 6 does not contribute to the oscillating operation in the initial state when the power is turned on, the ceramic resonator 6 is equivalent to a simple capacitor. On the other hand, in a stable state in which the ceramics vibrator 6 vibrates after a certain period of time and contributes to oscillation, the ceramics vibrator 6 does not have a simple capacitor equivalent, but a specific relatively high Q that can be represented by an equivalent circuit such as a capacitor and a coil. Form a vibrating circuit that you have.

Therefore, CR oscillation is performed in the initial state of startup, and after a certain period of time, it shifts to oscillation by ceramics. An equivalent circuit of each oscillation in these cases is shown in FIG.
(B).

C _{0 in} FIG. 2A is an equivalent capacitance when the ceramic oscillator 6 is not in an oscillating state, and the circuit in this case is
It is a so-called CR oscillator circuit. The equivalent circuit in the oscillation state of the ceramics vibrator 6 is as shown in FIG.

In the oscillation circuit shown in FIG. 4A, the capacitor 4 and
A capacitor having a total capacity consisting of an equivalent capacity C ₀ of the ceramic resonator 6 connected in parallel with this and a series circuit of the capacitor 5 is connected in series with the resistor 3, and thereby CR
A time constant circuit is formed. Then, CR oscillation is performed between this and the hysteresis inverting amplifier circuit 1, and the oscillation frequency is adjusted by selecting the value of the resistor 3 and the value of the capacitor 4. The oscillation frequency in this case is
The resistance value of the resistor 3 and the total capacitance of these capacitance circuits consisting of the capacitors 4 and 5 and the ceramic oscillator 6 in series with the resistance value, the ratio of the equivalent capacitance C ₀ to the capacitor 5, and the hysteresis. It is determined by the points of the inversion voltage on the upper side and the lower side of the inverting amplifier circuit 1. At this time, the feedback voltage fed back to the input side of the hysteresis inverting amplifier circuit 1 is a voltage divided by the ceramics vibrator 6 and the capacitor 5.

Therefore, assuming that the upper inverting voltage point (hereinafter UTP) and the lower inverting voltage point (hereinafter LTP) of the hysteresis inverting amplifier circuit 1 are between the ground potential and the power supply voltage VDD, when performing CR oscillation. The condition is that the feedback voltage is generated over the range before and after the voltage values of these inversion voltage points are exceeded. Note that UTP and LTP are usually adopted above and below VDD / 2, but if C <C ₀ , LTP can be set near VDD / 2 and the time until oscillation starts can be shortened. it can.

Here, assuming that the capacitance of the capacitor 5 is C, the voltage divided by the ceramic oscillator 6 and the capacitor 5 needs to be about VDD / 2. Capacitance C ₀ and capacitor 5
The relationship with the capacitance C of C is in the range of C <C ₀ . Also this CR
Unless the oscillation frequency due to oscillation is close to the oscillation frequency due to the ceramic oscillator 6, the smooth transition from CR oscillation to ceramic oscillator oscillation cannot be performed.

A case where the value of the capacitor 5 is selected under such a condition and the oscillation circuit of FIG. 1 is started will be described.
In the equivalent circuit of FIG. 2 (a), first, the input side of the hysteresis inversion amplifier circuit 1 becomes LOW level (hereinafter "L"), and the output side thereof becomes HGIH level (hereinafter "H"). Therefore, the capacitor 5 is charged from “L” via the resistor 3 and the capacitor C ₀ of the ceramic vibrator 6, and gradually rises from the ground potential at the start of oscillation. Then, the voltage at this point eventually exceeds the UTP of the hysteresis inverting amplifier circuit 1. At this time, the capacitor 4 is also charged via the resistor 3 at the same time.

When the capacitor 5 is charged to a voltage exceeding UTP,
The output of the hysteresis inversion amplification circuit 1 becomes "L", and the electric charge of the capacitor 5 is the ceramic oscillator 6 and the resistor 3 this time.
Through the resistor 3, and at the same time, the electric charge of the capacitor 4 is also discharged through the resistor 3.

With this discharge, the terminal voltage of the capacitor 5 drops, and when this voltage drops below LTP, the output of the hysteresis inverting amplifier circuit 1 changes from "L" to "H",
The capacitor 5 is charged again.

In the above case, the capacitance of the capacitor 4 may be selected within the range of ceramic oscillation operation.
Oscillation, except for adjustment of the oscillation frequency, capacitor 5
And the capacity ratio of the ceramic vibrator 6 are related.

In this way, CR oscillation is performed. Then, with respect to the ceramic oscillator oscillation that stably oscillates after a fixed time from the start, the equivalent circuit of FIG. 2 (b) is transferred, and Colpitts oscillation is performed in accordance with this.

Therefore, if a clock signal is generated using such an oscillation circuit, the clock signal can be obtained in a relatively short time, and if it is used in a device such as a Remoto control device, the standby start-up time can be shortened, and an external circuit Will be easy. In addition, it can be used for an oscillation circuit under various similar conditions.

As described above, the selection of the capacitance ratio between the capacitor 5 and the ceramic oscillator 6 that contributes to the CR oscillator circuit is related to the LTP and UTP of the hysteresis inverting amplifier circuit 1 and the oscillator frequency of the ceramic oscillator. However, it is not limited to the embodiment.

In the hysteresis inverting amplifier circuit of the embodiment, the ground potential has the reference potential, and LTP and UTP are on the positive side with respect to the ground potential, but this may have both on the negative side. Is not limited to ground potential.

Further, although the ceramic oscillator is used in the embodiment, a quartz oscillator, a ferrite oscillator, or the like can be used, and so-called solid oscillators in general can be used.

[Effects of the Invention] As can be understood from the above description, according to the present invention, the solid state oscillator and the first and second capacitors of the CR oscillator circuit are arranged in parallel, and the first and second capacitors are arranged in parallel. By setting the connection point of the second capacitor to the reference potential, the clock signal is obtained by CR oscillation in the initial state when the power is supplied to the oscillation circuit and the oscillation circuit is started.
The clock signal is continuously obtained by shifting from oscillation to oscillation by the solid-state oscillator.

As a result, a stable clock signal can be obtained in a relatively short time from the time of activation. Moreover, since the operation at the time of starting the computer or the like is often a specific program process that does not require an accurate clock signal, the computer side can be immediately started, and in a remote control device or the like, A device having a simple circuit and good response can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment in which the solid oscillator oscillating circuit of the present invention is applied to a ceramics oscillating circuit, FIG. 2 (a) is an equivalent circuit in the case of the CR oscillating circuit, and FIG. ) Is an equivalent circuit in the case of the ceramics oscillation circuit, and FIG. 3 is a general timing chart for standby-starting a computer receiving a clock signal. 1 ... Hysteresis inversion amplifier circuit, 2 ... Hysteresis inverter, 2a ... Feedback resistor, 3 ... Resistor,
4,5 ... Capacitor, 6 ... Ceramic oscillator, C ...
... Capacity of capacitor 5, C ₀ ... Equivalent capacity of ceramic oscillator 6.

Claims (2)

(57) [Claims] 1. A hysteresis inversion amplifier circuit having an upper inversion voltage point and a lower inversion voltage point, which are either positive or negative with respect to a reference potential, and a resistor from the output side to the input side of the hysteresis inversion amplifier circuit. A series circuit in which a first capacitor and a second capacitor are connected in this order;
And a solid oscillator connected in parallel to the second capacitor, the connection point side of the first capacitor and the second capacitor being set to the reference potential, the capacitance component of the solid oscillator and the series circuit. The oscillation frequency of the solid-state oscillator is equal to or near the oscillation frequency of the solid-state oscillator, and a solid-state oscillator circuit is provided. 2. When the capacitance component of the solid oscillator is C ₀ and the capacitance of the second capacitor is C, the relation between C and C ₀ is C <C _0.
The solid-state oscillator circuit according to claim 1, wherein: