JPH02277317A - Oscillation circuit - Google Patents

Abstract

PURPOSE:To reduce the oscillation operating time and to attain low power consumption by providing an oscillation circuit main body, a delay signal generating circuit in response to application of power, and a resistance control circuit controlling a current of the oscillation circuit main body and decreasing the resistance at the start of oscillation and increasing the resistance after the oscillation is made stable. CONSTITUTION:A level of an output terminal 6 of a delay signal generating circuit 2 is low immediately after application of a power supply 4, P-channel transistors (TRs) 31, 32 are both turned on, a large current is supplied to an oscillation circuit main body 1, which is oscillated. After a delay time elapses, the resistance of the TR 32 is gradually increased and only the TR 31 keeps the on-state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an oscillation circuit that supplies a clock signal to an information processing integrated circuit such as a microcomputer.

[Conventional technology]

2. Description of the Related Art In recent years, information processing devices such as microcomputers are required to further increase their information processing speed and reduce their power consumption. Particularly when using a battery power source, low power consumption is essential. Additionally, information processing equipment etc. are set to standby mode when not in use.
Along with this, the oscillation circuit is also put into a stopped state to reduce power consumption as much as possible. When the information processing device or the like is in use, it is necessary to start the oscillation operation of the oscillation circuit as quickly as possible to bring the information processing device or the like into the operating state.

[Problem to be solved by the invention]

Conventionally, in order to shorten the rise time of the oscillation operation after the oscillation circuit is powered on, the capacity of the oscillation circuit is increased and the energy supplied to the oscillation element, such as a connected crystal resonator or ceramic oscillation element, is reduced. It is necessary to make it larger.

However, increasing the energy supplied to the oscillation element in this way leads to an increase in power consumption, which goes against the goal of reducing power consumption. Therefore, it has been extremely difficult to satisfy both the shortening of the rise time of the oscillation operation of the oscillation circuit and the reduction of power consumption.

An object of the present invention is to provide an oscillation circuit that can achieve both shortening of the rise time of oscillation operation and low power consumption.

[Means to solve the problem]

The oscillation circuit of the present invention includes an oscillation circuit main body, a delay signal generation circuit that generates a delay signal in response to power-on, and a current supplied from a current supply source to the oscillation circuit main body by changing a resistance value according to the delay signal. A resistance control circuit is provided to control the resistance.

The delayed signal generation circuit generates a delayed signal having a delay time longer than the time required for the oscillation operation of the oscillation circuit to stabilize after power is turned on. In addition, the resistance control circuit is connected to an oscillation circuit in response to a delayed signal.The oscillation circuit shown in FIG. A circuit 2 is provided to supply current from the current supply source 4 to the oscillation circuit main body 1 by changing the resistance value of a variable resistor provided in the power supply path from the current supply source 4 to the oscillation circuit main body 1 according to the delayed signal. A resistance control circuit 3 is provided to control the current.

In this case, the delayed signal generation circuit 2 generates a delayed signal having a delay time longer than the time required for the oscillation operation of the oscillation circuit main body 1 to stabilize after power is turned on. Furthermore, in response to the delay signal, when the oscillation circuit main body 1 starts oscillating, the resistance control circuit 3 reduces the resistance value of a variable resistor provided in the power supply path from the current supply source 4 to the oscillation circuit main body 1 to oscillate. A large current is supplied to the circuit body 1, and after the oscillation of the oscillation circuit body 1 stabilizes, the resistance value of the variable resistor is increased to narrow down the current supplied to the oscillation circuit body 1 to the minimum value that can maintain oscillation. ing.

5 is the output terminal of the oscillation signal, from which a large current is supplied to the oscillation circuit by reducing the resistance value when the output unit starts oscillating, and after the oscillation of the oscillation circuit stabilizes, the resistance value is increased. The current supplied to the oscillation circuit body is narrowed down to the minimum value that can maintain oscillation.

[For production]

In the configuration of the present invention, the resistance control circuit reduces the resistance value and increases the current supplied to the oscillation circuit body when the oscillation circuit body starts oscillating, using the delay signal. As a result, a large current is supplied to the oscillation circuit main body, and the oscillation operation starts up quickly.

In addition, after the oscillation operation of the oscillation circuit body has stabilized, the resistance control circuit increases the resistance value to narrow down the current value supplied to the oscillation circuit body to a value close to the minimum value that allows the oscillation circuit body to maintain oscillation. become.

〔Example〕

FIG. 1 is a block diagram showing the configuration of an oscillation circuit according to an embodiment of the present invention.

The generated oscillation signal is used as a clock signal after its waveform is shaped by, for example, an inverter. 6 is a delayed signal output terminal.

In this oscillation circuit, a delay signal generated from the output terminal 6 of the delay signal generation circuit 2 in response to power-on causes the resistance control circuit 3 to control the resistance of the variable resistor when the oscillation circuit main body 1 starts oscillating after the power is turned on. The current supplied to the oscillation circuit main body 1 is increased by decreasing the value. As a result, the oscillation circuit main body 1
In this case, a large current is supplied from the current supply source 4, and the oscillation operation starts up quickly, so that the start-up time of the oscillation operation is shortened.

Also, after a predetermined period of time has passed after the power is turned on, the oscillation circuit main body 1
After the oscillation operation has stabilized, the resistance control circuit 3 increases the resistance value of the variable resistor to narrow down the current value supplied to the oscillation circuit body 1 to a value close to the minimum value at which the oscillation circuit body 1 can maintain oscillation. It turns out. As a result, the power consumption of the oscillation circuit main body 1 is suppressed to a minimum after the oscillation operation is stabilized.

In this way, this oscillation circuit can shorten the rise time of oscillation operation and achieve low power consumption, so it can be used as a clock signal supply circuit for high-speed, low-power information processing devices, etc. It is suitable as

FIG. 2 is a waveform diagram showing an example of the signal waveform of each part in the oscillation circuit shown in FIG. This is the obtained oscillation signal (voltage), and 6 is the delayed signal (voltage) obtained from the output terminal 6 of the delayed signal generation circuit 2.

The operation of the oscillation circuit will be explained below with reference to FIG. When the power is turned on, the voltage 4 of the current supply source 4 quickly rises and reaches a constant value. Voltage of this current supply source 4■4
When the value exceeds a certain value, the oscillation circuit main body 1 starts an oscillation operation, and an oscillation signal 5 whose amplitude increases is obtained. At this time, the rate of increase in the amplitude of the oscillation signal V5, that is, the rise time of the oscillation operation, is because the delay signal (2) is low, and therefore the resistance value of the variable resistor of the resistance control circuit 3 is low; A generating circuit 2 is configured.

In this case, the value of the delay time can be controlled by changing the values of the P-channel transistor 21 and the capacitor N22, and there is no problem with LSI integration.

Further, 31 and 32 are P-channel transistors, each functioning as a resistor, and constitute the resistance control circuit 3.

Its operation is as follows. Immediately after the power is turned on, the delay signal ■6 obtained from the output terminal 6 of the delay signal generation circuit 2
(see FIG. 2) is at a low level, and both P-channel transistors 31 and 32 are on. Therefore, power is supplied from the current supply a4 to the oscillation circuit main body 1 through both the P-channel transistors 31 and 32, and therefore a large current is supplied to the oscillation circuit main body 1. As a result, the rise time of the oscillation operation of the oscillation circuit main body 1 becomes shorter.

After the oscillation circuit main body 1 starts oscillating, the delay signal 6 gradually rises, and when a certain delay time has elapsed, the delay signal 6 becomes high level. At this time, Pcha is sufficiently early.

Thereafter, after the oscillation operation of the oscillation circuit main body 1 has stabilized, the amplitude of the oscillation signal (2) 5 decreases due to an increase in the resistance value of the variable resistor of the resistance control circuit 3 as the delay signal (6) rises, and the power is turned down. The amplitude at this time may be large enough to drive, for example, a frequency dividing circuit in the next stage.

FIG. 3 is a circuit diagram showing a circuit embodying the blocks of FIG. 1.

FIG. 3 shows an example of a circuit in the case of a CMO3 circuit.

In the figure, 11 is a P-channel transistor;
2 is an N-channel transistor 12, which constitutes an oscillation inverter. 13 and 14 are capacitors, 15 is an oscillation element such as a crystal resonator or a ceramic oscillator, and 41 and 42 are an N-channel transistor and a P-channel transistor, respectively, which form feedback resistance for oscillation. Configure.

Further, 21 is a P-channel transistor for forming a delay time, 22 is a capacitive channel transistor 32 formed of an oxide film, and the resistance value is gradually increased from the on state.
Eventually, it will be cut off and only the P-channel transistor 31 will remain on. Therefore, the current supplied to the oscillation circuit main body 1 is only the current supplied through the P-channel transistor 31. By designing the current supplied through this P-channel transistor 31 to the minimum value that allows the oscillation circuit main body 1 to maintain oscillation, power consumption during stable oscillation of the oscillation circuit main body 1 can be minimized. .

In the above embodiment, the circuit configuration of the present invention is applied to a CMO3 circuit, but it goes without saying that the circuit configuration of the present invention can also be applied to an NMO3 circuit and a PMO3 circuit.

In addition, the oscillation circuit main body 1. The specific circuits of the delay signal generation circuit 2 and the resistance control circuit 3 are not limited to the circuit shown in FIG. 3, but may be appropriately designed depending on the circuit type of the integrated circuit to which it is applied.

〔Effect of the invention〕

According to the oscillation circuit of the present invention, the rise time of the oscillation operation can be shortened by supplying a large current to the oscillation circuit main body when oscillation starts, and after the oscillation has stabilized, the current supplied to the oscillation circuit main body can be reduced. By limiting it, power consumption during use can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an oscillation circuit according to an embodiment of the present invention, FIG. 2 is a waveform diagram of each part of the circuit in FIG. 1, and FIG.
The figure is a circuit diagram showing a circuit embodying each block of FIG. 1. 1... Oscillation circuit main body, 2... Variable resistance circuit, 4...
・Power supply, 6...delay circuit

Claims (1)

[Claims] an oscillation circuit main body, and a delay signal generation circuit that generates a delay signal having a delay time longer than the time required for the oscillation operation of the oscillation circuit main body to stabilize after power-on in response to power-on;
a resistance control circuit that controls the current supplied from the current supply source to the oscillation circuit main body by changing the resistance value according to the delay signal output from the delay signal generation circuit, and the resistance control circuit controls the current supplied from the current supply source to the oscillation circuit main body. In response to the delay signal, when the oscillation circuit main body starts oscillating, the resistance value is reduced to supply a large current to the oscillation circuit main body, and after the oscillation of the oscillation circuit main body stabilizes, the resistance value is increased to supply a large current to the oscillation circuit main body. An oscillation circuit that narrows down the current supplied to the circuit to the minimum value that can maintain oscillation.