Citizen Watch Company, Ltd.

Citizen Finedevice Co., Ltd.

Citizen Holdings Company, Ltd.

Citizen Finetech Miyota Co., Ltd

Rikoku Nakamura

Masanori Yomoyama

Shigeru Morokawa

Hitoshi Satsuta

Takashi Masuda

Takakazu Yano

Tetsuya Aiba

Yuta Kanamori

Yukio Otaka

Takuo Furuki

Takahiko Sato

In piezoelectric sensors, conventional amplification factor adjustment methods involving the cutting of a wiring pattern or use of a laser trimmable resistor are unable to adjust the amplification factor when the sensor is in a completed state. As a result, the production process becomes complex and production costs increase. Further, because the amplification factor adjustment is carried out in a different state from that of the finished product, the problem that the amplification factor is not set correctly in the finished product also occurs. A non-volatile memory is incorporated in an integrated circuit in which there are integrated piezoelectric sensor circuit elements. The amplification factor is adjusted by writing data from a writing terminal to change an amplification resistor a.

Piezoelectric sensor

A disconnection detection circuit includes: a pull-up resistor to which the detection signal is fed and which connects a signal line connected to the wiring cable to a power supply or a pull-down resistor which connects the signal line to a GND; and a voltage clip circuitwhich includes a high-voltage clip circuit which is connected between the signal line and the power supply and which clips the voltage of the signal line to the maximum specified voltage and a low-voltage clip circuit which is connected between the signal line and the GND and which clips the voltage of the signal line to the minimum specified voltage.

Disconnection detection circuit of pressure detection device

There is provided a pressure detection device () including: a pressure detection element () which receives pressure (P) so as to output a detection signal (Qi) corresponding to the pressure (P); and a processing circuit () which processes and outputs the detection signal (Qi) output from the pressure detection element (), where on a circuit board () on which a conductor pattern is formed, an integrated circuit (IC) including an analog circuit which uses a reference voltage (Vr) set to a predetermined voltage value as an operation reference and converts the detection signal (Qi) into a voltage waveform is mounted, and the processing circuit () includes an input circuitwhich feeds the detection signal (Qi) to the integrated circuit (IC) and a shield pattern (SHP) which surrounds the region of at least a part of the input circuit () and to which the reference voltage (Vr) is applied.

Pressure detection device

A processing circuit is provided which includes at least an integrator circuit which uses a reference voltage set to have a predetermined magnitude as an operation reference and which integrates a detection signal so as to convert the detection signal into a voltage waveform and a base voltage adjustment circuit which is connected between an input terminal and an output terminal of the integrator circuit and which adjusts the magnitude of a base voltage that is a potential when the detection signal in an output signal output from the integrator circuit is not present. As another form, a processing circuit can be adopted which includes at least one or more amplifier circuits which amplify an output signal from an integrator circuit and a base voltage adjustment circuit which is connected between a supply portion of a reference voltage fed to the amplifier circuit and an input terminal of at least one of the amplifier circuits and which adjusts the magnitude of a base voltage that is a potential when a detection signal in an output signal output from the amplifier circuit is not present.

A temperature detection circuit () detects temperature around an oscillation circuit () equipped with voltage variable capacitors (). According to its temperature detection signal, a temperature compensation circuit () produces a voltage signal as a temperature compensation signal. That voltage signal is supplied to the voltage variable capacitors () in order to sustain oscillation frequency of the oscillation circuit () at a substantially constant level. When a switch element () is, turned on by a non-TCXO signal, both terminals of each voltage variable capacitor () are brought to the same potential (ground potential). Consequently, each voltage variable capacitor has a predetermined capacitance and temperature compensation function is made ineffective. In that state, initial frequency regulation is performed under normal temperature.

Temperature compensation oscillator and method for manufacturing the same

Disclosed is an integrated voltage-controlled crystal oscillator intended to present the conditions for circuit constants in an oscillator circuit that can improve the oscillator's frequency tuning range with respect to the variable capacitance range of a variable-capacitance element. The voltage-controlled crystal oscillator comprises a crystal, an amplifier, and a load capacitor, wherein the load capacitor includes a voltage-controlled variable-capacitance element integrated on a semiconductor substrate and a DC cut capacitor element connected in series with the voltage-controlled variable-capacitance element, and the DC cut capacitor element has a capacitance value (Ccut) whose ratio to a maximum capacitance value (Cvmax) of the voltage-controlled variable-capacitance element (Ccut/Cvmax) is more than 0.5 and not more than 10.

Voltage-controlled crystal oscillator

In an electronic timepiece, in which electric power generated by a solar cell (,) is accumulated in an accumulator device (,) and a time keeping means (,) is driven with the accumulated electric power, an electrically on-off controllable switch (,) is provided in a circuit for charging the accumulator device (,) by the solar cell (,), a voltage comparison means (,) intermittently brings the switch (,) into the off-state at predetermined intervals and compares the generated voltage (Vs) by the solar cell and the accumulated voltage (Vb) in the accumulator device (,), and keeps the switch (,) in the off-state as it is when Vs&lE;Vb and brings the switch (,) into the on-state when Vs>Vb in accordance with the comparison result. Thereby, a reverse flow of an electric current from the accumulator device (,) can be prevented and a voltage drop on charging is eliminated, resulting in enhancement in charging efficiency.

Electronic timepiece

An LCD device comprising an LCD for changing the size of a displayed unit of pixels by electrically connecting a plurality of display electrodes in parallel with one another for time-sharing matrix driving liquid crystal pixels arranged as a matrix wherein image data is independently inputted into upper and lower half portions of the LCD, a display controller for outputting upper and lower side image data to be displayed on the upper and lower half portions of the LCD and synchronous signals. The LCD device further comprises an upper side image data-holding memory and a lower side image data-holding memory for dividing image data in a given display area from a screenful of image data outputted from the display controller into new upper and lower side image data to be written and held in the upper and lower side image data-holding memories. The upper and lower side image data held in the upper and lower side memories are read out to be repeatedly displayed on the upper and lower half portions of the LCD. As a result, the image from any desired display area of a full-screen area can be enlargedly displayed on a full-screen area of a display with high quality and be easily visible without being discontinuous.

Growing community of inventors

Yamanashi, Japan

Rikoku Nakamura