Citizen Watch Company, Ltd.

Yasuhiko Nishikubo

Mitsuo Sekine

Shigeru Morokawa

Heihachiro Ebihara

Yasushi Nomura

Yukio Hashimoto

Hiroyuki Fukayama

Toyoharu Fujikawa

Shingo Hashimoto

Tsutomu Tanaka

A temperature detector made by a CMOS integrated circuit. The temperature detector comprises a first constant voltage circuit for producing a first constant voltage, a second constant voltage circuit applied with the first constant voltage for producing a second constant voltage, and a ring oscillator applied with the second constant voltage for producing an output voltage dependent of ambient temperature. Each constant voltage circuit has a standard resistor in the form of a diffusion resistor, a current-mirror circuit as a standard voltage generating circuit, and a voltage follower, and the ring oscillator has a delay resistor formed by a MOS transistor.

Temperature detector

A quartz oscillation-type electronic timepiece which consumes less electric power, in which electronic circuits operate on a small constant voltage obtained by a constant-voltage circuit except the portions requiring a relatively high voltage such as display device unit.

Quartz oscillation-type electronic timepiece

An electronic timepiece having a quartz crystal oscillator for producing a time standard signal, a frequency divider, and a display device. A CMOS integrated circuit on an N-type substrate is provided for the elements. A first aluminum lead and a second aluminum lead are provided on the CMOS integrated circuit. The first aluminum lead is provided on the CMOS integrated circuit to connect the high potential side of voltage supply to the N-type substrate. The second aluminum lead is provided on the CMOS integrated circuit for supplying the voltage to a logic circuit in the CMOS integrated circuit. A resistor is provided between the second aluminum lead and high potential side of the voltage supply for preventing the latch-up of the CMOS integrated circuit.

Electronic timepiece

An electronic timepiece comprising a quartz crystal oscillator for producing a time standard signal, a frequency divider, and a display driver. The electronic circuit comprises a digital logic circuit employing a complementary MOS integrated circuit (CMOS.multidot.IC). A diffusion resistor is formed in the N-type substrate of the CMOS transistor of the CMOS.multidot.IC by diffusing an impurity at the same time with the diffusion of the P-well for the N-channel MOS transistor of the CMOS transistor. Supply voltage of a battery is supplied to a part of the CMOS.multidot.IC through the diffusion resistor, whereby variation of the threshold voltage of the CMOST may be compensated.

Electronic timepiece with diffusion resistor for compensating threshold

A electronic timepiece having a dynamic frequency divider, a static frequency divider and a reset system, in which a switching means is provided in the voltage supply circuit of the dynamic frequency divider and a gate means is provided between the dynamic frequency divider and the static frequency divider. The switching means is a transistor adapted to be cut off to stop the operation of the dynamic frequency divider in the reset state and the gate means is a digital logic gate adapted to fix the output thereof by an input voltage applied by the reset system, whereby power consumption in the dynamic frequency divider and in the static frequency divider may be reduced.

An analogue electronic timepiece is described having an oscillator, a frequency divider, a hand display means, an hour and minute circuit for counting the output of the frequency divider, and an alarm setting circuit. An equality checking circuit adapted to compare the output of the hour and minute circuit with the output of the alarm setting circuit to produce a coincidence signal. An alarm device is operated by the coincidence signal, gate means, and a manual switch. The gate means is so arranged to produce a signal for setting an alarm time in the alarm setting circuit in accordance with the closing of the switch.

Analogue electronic timepiece with an alarm device

A crystal oscillation-type electronic timepiece having an oscillator with a crystal oscillator as a time base, means for dividing the frequency of the oscillator, display driving means and time display means. The oscillator has a complementary metal oxide semiconductor logic circuit including an inverter with a gated N-channel transistor and a gated P-channel transistor. The inverter is designed such that a ratio of the width and length in a channel of the gated N-channel transistor is made less than one and that a ratio of the width and length in a channel of the gated P-channel transistor is made less than two. The capacity of an input capacitor connected to an input of the crystal oscillating element is larger than that of an output capacitor connected to an input of the crystal oscillating element. The consumed power at the oscillating part is thereby decreased.

Crystal oscillation-type electronic timepiece

In an electronic timepiece having an analog type of time display by means of hours and minutes hands, an alarm system is provided which functions electronically and independently of the analog display system. An alarm signal is generated when the time duration counted by an alarm timekeeping circuit coincides with an alarm time stored in an alarm time memory circuit, said alarm time being set by the timepiece user actuating a switch.

Electronic timepiece having an alarm system

An electronic alarm timepiece comprises a quartz crystal oscillator, a frequency divider, a display driving means, a display means, an alarm signal shaping means and an alarm means. The alarm signal shaping means is so arranged that a pair of output signals which are opposite in phase are produced with the aid of output signals of the frequency divider for actuating the alarm means, whereby it is possible to provide an alarm signal shaping means in the form of a complementary metal oxide semiconductor (CMOS) integrated circuit having sufficient power to actuate the alarm means without other amplifying circuits.

Electronic alarm timepiece

A display control circuit for an electronic timepiece for controlling a timer circuit to vary the length of time for which the display of time or calendar information is to be made. In one preferred embodiment, a timer circuit includes a first section of flip-flops for setting a predetermined length of time when a first external switch is operated, and a second section of flip-flops for setting time interval in addition to the predetermined length of time when a second external switch is operated. A control circuit means is coupled to the timer circuit for controlling the same to vary the total length of time to be set by the timer circuit. In another preferred embodiment, the timer circuit is energized with selected one of frequency signals from a frequency converter of the electronic timepiece to set the length of time in dependence on the selected one of the frequency signals. The frequency signals are selected by operating the external switch a predetermined number of times or by continuously operating the external switch for a prescribed time interval.

Display control circuit for electronic timepiece

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.

An electronic timepiece with a crystal-controlled oscillator includes a multistage frequency divider and a CMOS switching circuit inserted between the oscillator and the first divider stage. The switching circuit comprises two complementary MOSFETs, with insulated gates connected in parallel to an output lead of the oscillator, and at least one further MOSFET in series with the other two, the latter having an insulated gate connected to another output lead of the oscillator for energization in staggered relationship with the former to bring about simultaneous conduction for one brief instant per half-cycle of the generally sinusoidal oscillator voltage. With an oscillator operating at a frequency on the order of megahertz, the divider stages may form part of an upstream and a downstream frequency divider connected in cascade; the upstream divider may consist of nonbinary stages with individual step-down ratios of 3:1 or higher to minimize overall power consumption.

Crystal-controlled electronic timepiece with CMOS switching and

A temperature compensated electronic timepiece comprises a time reference signal generator for generating a time reference signal and a temperature compensating device for compensating a change of the oscillating frequency of the time reference signal generator caused by any external temperature change. The temperature compensating device comprises a temperature detector having an element composed of two semiconductors of different respective conductivities (such as a transistor composed of P and N type semiconductors) which are joined to form a junction, or an element composed of a conductor and a semiconductor joined to form a junction. The voltage-current characteristics of the junction are changed when the external temperature exceeds a given temperature to deliver a digital signal whose state is reversed from an initial condition. The output signal from the temperature detector compensates any temperature change of the oscillating frequency of the time reference signal generator.

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Iruma, Japan

Yasuhiko Nishikubo