Citizen Watch Company, Ltd.

Hiroyuki Fukayama

Yasuhiro Sakurai

Heihachiro Ebihara

Yasuhiko Nishikubo

Shingo Hashimoto

The temperature of an oscillation circuit ( ) is detected by a temperature detection circuit ( ), a cubic term voltage generation circuit of a control voltage generation circuit ( ) generates a cubic term voltage as a control voltage based on an output voltage of the temperature detection circuit ( ), and a frequency adjustment circuit ( ) changes an oscillation frequency of the oscillation circuit ( ) by the control voltage. The cubic term voltage generation circuit includes a first MOS transistor ( ) having a source connected to a first power line ( ), a second MOS transistor ( ) having a source connected to a second power line ( ), and digital control voltage division circuits ( ) for generating a first and a second gate voltage, respectively based on the output voltage of the temperature detection circuit ( ), in which the first and second gate voltages are applied to gates of the first and second MOS transistors ( ) respectively, and a connection point ( ) where respective drains are commonly connected shall be an output terminal of the control voltage.

Temperature compensated oscillator using a control voltage generation circuit

An insulating film and a conducting film are formed in that order on an N type semiconductor substrate to form a capacitor structure of &ldquo;conducting film&mdash;insulating film&mdash;semiconductor&rdquo;; a heavily doped P region having a high impurity concentration is provided on the N type semiconductor substrate to contact a covered region which is covered with the conducting film; and furthermore a heavily doped N region for conducting an electrode on the semiconductor side is provided and connected with the heavily doped P region, resulting in quickly variance of the capacitance values in accordance with the voltage applied between the heavily doped N region and a terminal of the conducting film.

Mis variable capacitor and temperature-compensated oscillator using the same

A constant voltage generation circuit (,) for driving a temperature-compensated crystal oscillation circuit (,) comprises a differential circuit (,), a dc load (,) for supplying feedback signals to the differential circuit (,), a driver (,) for driving the dc load (,) and the temperature-compensated crystal oscillation circuit (,) under control by control signals outputted by the differential circuit (,), and a low-pass filter (,) made up of passive elements only and for applying the control signals to the driver (,) after removing high frequency components out of the control signals, thereby preventing an increase of phase noise while achieving low power consumption.

Temperature-compensated crystal oscillator having constant voltage generator with filter

In a temperature-compensated crystal oscillator wherein a temperature-compensated crystal oscillation circuit is driven by a constant voltage generation circuit, the constant voltage generation circuit comprises a differential circuit, a dc load for supplying feedback signals to the differential circuit, a first driver for driving the dc load under control of the differential circuit, a phase-compensation capacitor coupled between a control terminal of the first driver and an output terminal thereof and a second driver for driving the temperature-compensated crystal oscillation circuit. The second driver is the same kind of device as is used for the first driver, and is under control by the same control signal as a control signal for the first driver, sent out by the differential circuit.

Temperature-compensated crystal oscillator

In a temperature-compensated crystal oscillator, a series connection of an AT-cut crystal resonator, a MOS capacitor, and a first fixed capacitor is coupled in parallel with an amplifier and a second fixed capacitor, making up a crystal oscillation circuit. A first control signal generating circuit for temperature compensation is connected directly or via a first input resistor to one terminal of the MOS capacitor of the crystal oscillation circuit, and a second control signal generating circuit for temperature compensation is connected dirty or via a second input resistor to the other terminal of the MOS capacitor. The first control signal generating circuit serves as a rectilinear correction signal generating circuit on the lower temperature side while the second control signal generating circuit serves as a rectilinear correction signal generating circuit on the higher temperature side.

An electronic timepiece having an electronic circuit which comprises a monolithic integrated circuit including a multistage amplifier. The amplifier of the circuit is so designed that an amplitude control component, which has been considered indispensable in the existing art, is unnecessary in the circuit, whereby various types of electronic timepieces are obtainable in a simple and compact manner by applying the monolithic circuit to different types of oscillator means.

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Sayama, Japan

Hiroyuki Fukayama