Seiko Instruments Inc

Minoru Sudou

Kenji Kato

Mitsuo Yarita

Yotaro Nihei

Mika Shiiki

Kenji Katou

Hitsuo Yarita

Kenji Kanou

Provided is a voltage regulator having low current consumption, which is capable of preventing a reverse current from flowing thereto from an output terminal (), irrespective of a magnitude of a voltage of a VDD terminal (). The voltage regulator has a circuit configuration in which voltage dividing resistors are not used for a comparator circuit for comparing the voltage of the VDD terminal () with a voltage of the output terminal (), to thereby achieve lower current consumption.

Voltage regulator

Provided is a voltage regulator capable of securely preventing a reverse current from an output terminal () with lower current consumption, irrespective of magnitude of a voltage of a VDD terminal (). Such a configuration is adopted that the voltage of the VDD terminal () and a voltage of the output terminal () of the voltage regulator are compared with each other with the use of a voltage generated between a transistor and a constant current circuit, to thereby reduce current consumption of a backup battery. Besides, such a configuration is also adopted that a gate of an output transistor is connected with the output terminal () based on an output of a comparator circuit, to thereby prevent the reverse current securely.

Provided is a voltage regulator capable of stable operation under a light load so as to cover a wide range of load capacitances. The voltage regulator includes a circuit for charging a phase compensation capacitor for the voltage regulator, and a zero due to a resistor () and a capacitor () appears at low frequency.

Provided is a CMOS operational amplifier circuit that can operate with low noise, with low current consumption, and with stability. A cascode bias voltage of a folded cascode circuit in the CMOS operational amplifier circuit is modulated by a current at an input differential stage, thereby enabling operation with low noise, with low current consumption, and with stability.

Operational amplifier circuit

A capacitance-type dynamic-quantity sensor has a silicon substrate having etched recessed upper and lower surface portions forming a weight supported by beam portions and mounted to undergo displacement due to an applied external dynamic quantity such as acceleration or angular velocity. An upper glass substrate is bonded to a part of the upper surface of the silicon substrate and is laminated with a first fixed electrode disposed opposite to and spaced apart from the weight with a first space therebetween formed by the etched recessed upper surface portion of the silicon substrate. A lower glass substrate is bonded to a part of the lower surface of the silicon substrate and is laminated with a second fixed electrode disposed opposite to and spaced apart from the weight with a second space therebetween formed by the etched recessed lower surface portion of the silicon substrate.

Capacitance-type dynamic-quantity sensor and manufacturing method therefor

A capacitive dynamic quantity sensor whose size is small and whose reliability and mass productivity are high is provided. In order to realize signal transmission from a lower electrode to an upper electrode, silicon columns which are electrically isolated from one another but not mechanically isolated from one another are formed to connect both electrodes.

Capacitive dynamic quantity sensor and semiconductor device

A charge pump circuit is provided which outputs a high voltage by using a boosting circuit with a smaller number of stages. A diode is used to give a back-gate voltage for a MOS transistor composing the charge pump circuit, thereby minimizing a reduction in a boosted voltage due to an increase in the threshold voltage of the MOS transistor. In addition, a second MOS transistor is provided between the back gate of the MOS transistor and the ground (GND) such that in-phase clock signals are inputted to the gate of the second MOS transistor and the capacitor thereof.

Charge pump circuit

A CV conversion circuit capable of measuring a plurality of capacitances with a simple circuit is provided. A time-division signal is applied to each capacitor, whereby a plurality of capacitances of the capacitors can be measured in series by a circuit with a small number of components.

Current-voltage conversion circuit

A capacitive sensor for measuring a dynamical quantity based on a change in capacitance has a semiconductor substrate having a weight supported by beams so as to undergo displacement according to the dynamical quantity. The semiconductor substrate is sandwiched between glass substrates on which fixed electrodes are disposed in a position facing the weight with minute gaps existing between the glass substrates and the weight. A substrate electrode is disposed on one of the glass substrates and contacts a part of the semiconductor substrate. A recess having a size equal to or larger than a contact area in which the semiconductor substrate contacts the substrate electrode is formed in the semiconductor substrate, and a contact electrode is disposed in the recess in contact with the substrate electrode.

Capacitive sensor for dynamical quantity

A voltage detecting circuit that has a stable output even when a battery voltage is low includes first and second terminals connected across poles of a battery, a reference voltage generating circuit, and a comparator for comparing values of the reference voltage and voltage across the terminals. A first output circuit is connected between the first and second terminals to output a first output signal on the basis of the comparison result, a second output circuit outputs a second output signal that changes in value based on a voltage of the battery and on the basis of signals at the first and second terminals, and an output terminal outputs the first and second output signals.

Voltage detecting circuit

A voltage regulator which suppresses an inrush current at the time of power application has input and output terminals, a power supply connected to the input terminal, a switch circuit connected to the power supply, a coil connected between the switch circuit and the output terminal, a rectifying device connected in series between the coil and the output terminal, an output capacitor connected to the output terminal, a switching element connected between the coil and the rectifying device, a driving circuit for driving the switching element, a transistor connected between the power supply and the coil, and a control circuit connected to the transistor for gradually varying an ON resistance of the transistor from a relatively large value immediately after the switch circuit is turned on to a relatively small value a predetermined time thereafter to limit a rush current flowing into the output capacitor from the power supply.

Booster type switching regulator

A voltage regulator comprises a differential amplifier for comparing an output of a reference voltage circuit with an output of a voltage dividing circuit and outputting a first signal and a phase compensating circuit having a resistor and a capacitor connected in series. A MOS transistor is connected between a power supply and the phase compensating circuit and has a gate electrode connected to receive the output of the differential amplifier and a grounded source. A constant current circuit is connected between the MOS transistor and ground, and an output transistor having a gate electrode connected to receive a second signal output from a connection point between the MOS transistor and the phase compensating circuit is connected between the power supply and the voltage dividing circuit. A resistor side of the phase compensating circuit is connected to an output terminal of the differential amplifier and a capacitor side of the phase compensating circuit is connected to a drain electrode of the MOS transistor.

A semiconductor device has a semiconductor element formed on a semiconductor substrate and a first insulating film having contact holes. The semiconductor element has a gate electrode, a source region and a drain region. The semiconductor element also has metal wirings each for connecting a respective one of the contact holes to the gate electrode, the source region and the drain region of the semiconductor element. A second insulating film is formed on the first insulating film and the metal wirings. The second insulating film has a chemical-mechanical polished portion defining a flattened upper surface of the second insulating film. Resistors are formed on and are disposed directly in contact with the flattened upper surface of the second insulating film and are connected in series to form a bleeder resistor circuit or a ladder circuit.

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Chiba, Japan

Minoru Sudou