JPS62225004A - Oscillation circuit - Google Patents

Abstract

PURPOSE:To change the resistance of an inserted resistance control circuit between an oscillation circuit and a current supply source, to reduce the oscillation start time and the power consumption in operation by detecting the start of oscillation of the oscillation circuit to generate a delay signal. CONSTITUTION:A voltage V4 of a power supply 4 is fed to an oscillation circuit section l of an oscillation circuit via a variable resistance control section 2, the oscillation is started when the voltage V4 of the power supply 4 reaches a prescribed value to output an output waveform V6 at an oscillation output terminal 6. The output waveform V6 is detected by a signal generating circuit 10 and after a delay time elapsed till the oscillation is made stable, an output voltage V8 is outputted to a signal generating circuit output terminal 8. Then the output voltage V8 is fed to the section 2 to increase the resisance in the circuit thereby reducing the power consumption in operation and reducing the oscillation start time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an oscillation circuit that starts oscillation quickly and consumes little power.

Conventional technology Conventionally, in order to shorten the start time of an oscillation circuit after power is turned on, it is necessary to increase the capacity of the oscillation circuit and increase the energy supplied to the connected crystal resonator or ceramic oscillation element. However, this leads to an increase in power consumption, which is contradictory to low power consumption.

In recent years, information processing speeds have been increasing, and power consumption has been required to be reduced. Especially when using battery power, low power consumption is essential, and the circuit is set to standby mode when not in use, and the oscillation circuit is also stopped to reduce current consumption as much as possible.

On the other hand, when the circuit is in use, it is necessary to start oscillation and transition to an operating state as quickly as possible.

Conventionally, it has been difficult to achieve both.

Problems to be Solved by the Invention As described above, it has been difficult to satisfy the conflicting demands with conventional circuits. An object of the present invention is to provide a circuit that simultaneously achieves shortening of oscillation rise time and low power consumption.

That is, in order to solve the above problems, the present invention shortens the oscillation start time by supplying a large current to the oscillation circuit when oscillation starts, and after the oscillation is stabilized, the current supplied to the oscillation circuit is reduced. To provide a circuit that achieves low power consumption by limiting power consumption.

Means for Solving the Problems The present invention comprises an oscillation circuit, a circuit for detecting the start of oscillation of the oscillation circuit, a circuit for generating a delayed signal longer than the time required for the oscillation to stabilize, and a circuit for detecting the oscillation by the signal. This is an oscillation circuit consisting of a circuit that controls a variable resistance circuit inserted between the circuit and a current supply source to change its resistance value.

According to the present invention, at the start of oscillation, the resistance value of the variable resistance circuit is decreased to increase the current supplied to the oscillation circuit,
By shortening the oscillation start time and increasing the resistance value after oscillation has stabilized, the current value is narrowed down to around the minimum value of the oscillation sustaining current value, and the current consumption is controlled to the minimum. .

Embodiment FIG. 1 is a block diagram showing an embodiment of the oscillation circuit of the present invention. In Figure 1, 1 is an excavation circuit, 2 is a variable resistance control circuit, 4 is a power supply, 6 is a ground power supply, 6 is an oscillation circuit output terminal, and 1o is a signal generation circuit c with a time delay until oscillation is stabilized. (hereinafter referred to as an oscillation detection and delay circuit) Furthermore, 8 is its output signal.

FIG. 2 shows an example of a signal waveform, and when the power supply voltage v4 reaches a certain value or more, oscillation starts, and an output waveform v6 is output to the output terminal 6.
is obtained. It is assumed that after this oscillation is detected and a delay time until stabilization has elapsed, a signal of terminal voltage v8 is generated in the signal generating circuit 10.

The resistance value of the variable resistance control circuit 2 shown in FIG. 1 is increased by the signal of the terminal voltage v8 of the signal generation circuit 1o, and the oscillation width is decreased, thereby powering down.

The amplitude at this time only needs to be large enough to drive the next-stage frequency divider circuit.

A more specific example of the circuit is shown in FIG.

FIG. 3 shows the case of a 0M08 circuit. 11.

21 and 22 are P-channel transistors, and 12 is an N-channel transistor, and this pair forms an inverter portion of the excavation circuit. 13 and 14 are capacitors, and 15 is a crystal or ceramic oscillator. 21 and 22 are P-channel transistors connected in parallel and constitute a variable resistance circuit.

At the start of oscillation, the voltage v8 at the output terminal 8 of the signal generating circuit 1o is at the II L" level as shown in FIG. 2, and the parallel P-channel transistors 21 and 22 are both on and in a low resistance state. After a certain delay time after oscillation starts, the voltage at the output terminal 8 of the signal generation circuit 1o becomes "H".
As a result, the P-channel transistor 22 driven by this is turned off, and the current supplied to the excavation circuit has a value only through the transistor 21.

By designing the on-resistance value of the transistor 21 to be the minimum oscillation sustaining current, it is possible to suppress the current consumption after stable oscillation to the minimum value.

Note that this circuit configuration can also be applied to a circuit with an inverted transistor configuration (NMO8, PMO3).

Effects of the Invention As described above, according to the present invention, it is possible to shorten the oscillation start time and reduce power consumption during use, which is extremely effective for high-speed, low power consumption circuits. .

[Brief explanation of drawings]

Figure 1 shows that the oscillation circuit block in one embodiment of the present invention is 0MO.
FIG. 3 is an example circuit diagram in the case where No. 3 is used. 101. ...Oscillation circuit section, 2...Variable resistance side leg section, 10...Signal generation circuit, 4...Power supply, 5...Ground potential, 6 ...Oscillation output terminal, 8...Signal generation circuit output terminal, 11. ．．
21.22...P channel transistor, 12.
...N-channel transistor, 13.14...
...Capacitance, 16...Oscillation element (crystal or ceramic). Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3

Claims (1)

[Claims] A delayed signal generation circuit detects the start of oscillation of an oscillation circuit and generates a delayed signal, and means for changing the resistance value of a resistance control circuit inserted between the oscillation circuit and a current supply source using the delayed signal. Equipped with an oscillation circuit.