Oscillators – Solid state active element oscillator – Transistors
Patent
1999-01-07
2000-08-01
Grimm, Siegfried H.
Oscillators
Solid state active element oscillator
Transistors
331158, H03B 536
Patent
active
060972572
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to an oscillation circuit, an electronic circuit, a semiconductor device, electronic equipment, and a timepiece.
BACKGROUND ART
Oscillation circuits that use crystal oscillators are widely used in the art in applications such as timepieces and portable telephones and computer terminals. In such portable devices, it is necessary to design them to reduce power consumption and thus have longer battery lives.
From the viewpoint of reducing power consumption, the present inventors have analyzed the power consumptions of semiconductor devices that are installed in the electronic circuitry used in portable electronic equipment, particularly wristwatches. The results of this analysis show that the power consumption of the oscillation circuit parts of such a semiconductor device is far larger than that of the other circuits. In other words, the present inventors have discovered that reducing the power consumption of the oscillation circuit parts used in portable electronic equipment is effective for increasing battery life.
DISCLOSURE OF THE INVENTION
An objective of this invention is to provide an oscillation circuit, electronic circuit, semiconductor device, electronic equipment, and timepiece that can be driven at low power consumptions.
Another objective of this invention is to provide an oscillation circuit, electronic circuit, semiconductor device, electronic equipment, and timepiece wherein the effects of variations in the threshold voltages of transistors comprised within the signal inversion amplifiers of the oscillation circuit can be reduced, to enable stabilized oscillation.
In order to achieve the above objectives, the oscillation circuit of this invention comprises,
a signal inversion amplifier;
a feedback circuit having a crystal oscillator, for inverting the phase of an output signal of the signal inversion amplifier and feeding this inverted signal back as an input to the signal amplifier; and
a control circuit for controlling a back gate voltage between a back gate and a source of a transistor configuring the signal inversion amplifier.
This aspect of the invention makes it possible to utilize the body effect of a substrate bias actively, to ensure that the source potential of the transistor comprised within the signal inversion amplifier differs from the back gate potential thereof. This makes it possible to control the threshold voltage of the transistor and reduce the power consumption of the oscillation circuit when it is operating.
It is preferably that field effect transistors are used as transistors configuring the signal inversion amplifier.
Transistors configuring the signal inversion amplifier may comprise a first transistor and a second transistor; and
the control circuit may employ a configuration that controls the back gate voltage of the second transistor.
In addition, it is preferable that a depletion type of field effect-transistor is used as these transistors.
When the back gate of the second transistor is set to a predetermined potential, the control circuit may comprise:
a rectifier element circuit connected to the source of the second transistor;
a switching element that forms a bypass circuit for the rectifier element circuit; and
a switching circuit for selectively switching a back gate voltage of the second transistor over at least two stages, by on/off control of the switching element.
When the source of the second transistor is set to a predetermined potential, the control circuit may comprise;
a rectifier element circuit connected to a back gate of the second transistor;
a switching element that forms a bypass circuit for the rectifier element circuit; and
a switching circuit for selectively switching a back gate voltage of the second transistor over at least two stages, by outputting on/off control signals of the switching element.
This configuration makes it possible to select the threshold voltage of the second transistor in a stepwise manner by on/off control of the switching element, so that the oscillation circuit can be
REFERENCES:
patent: 4376918 (1983-03-01), Masuda et al.
Kadowaki Tadao
Makiuchi Yoshiki
Nakamiya Shinji
Grimm Siegfried H.
Seiko Epson Corporation
LandOfFree
Crystal oscillator circuit having transistor with back gate volt does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Crystal oscillator circuit having transistor with back gate volt, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Crystal oscillator circuit having transistor with back gate volt will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-667799