Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Kouji Nabetani

Hideyuki Murakami

Takashi Kawai

Kazuhiro Onaka

Masako Yamaguchi

Masataka Tagawa

Takehiko Ogawa

Nobukazu Hayashi

Yukio Nakao

An angular velocity sensor includes a vibration body, first and second sensor electrodes generating an electric charge responsive to an angular velocity applied to the vibration body, first and D/A converters each outputting at least two levels of an electric charge, first and second integrator circuits integrating the electric charge generated by the first and second sensor electrodes and the electric charges output from the first and second D/A converters, respectively, a comparator unit comparing output signals from the first and second integrator circuits, first and second D/A switching units switching levels of the output signals from the first and second D/A converters according to a comparison result of the comparator unit, a first disconnection detecting switch connected between the first sensor electrode and the first integrator circuit, a first voltage source for injecting an electric charge into a point between the first sensor electrode and the first integrator circuit via the first disconnection detecting switch, a second disconnection detecting switch connected between the second sensor electrode and the second integrator circuit, and a second voltage source for injecting an electric charge into a point between the second sensor electrode and the second integrator circuit via the second disconnection detecting switch. This angular velocity sensor has a high reliability and performs stable operation even if ambient environment changes.

Angular speed sensor

A PLL circuit is provided with an AD converter, a DA converter to which output from the AD converter is inputted, a filter circuit filtering an output signal of the DA converter, a voltage control oscillator outputting a signal of a different frequency in accordance with an output signal from the filter circuit and a frequency divider dividing a signal which the voltage control oscillator outputs. The AD converter operates by a timing signal from the voltage control oscillator and the DA converter outputs an analog signal corresponding to a value which the AD converter outputs by the timing signal outputted from the frequency divider.

PLL circuit and angular velocity sensor using the same

An angular velocity sensor has a stable output characteristic using a sigma-delta type analog-to-digital converter. The sigma-delta type analog-to-digital converter includes an integrator unit for integrating electric charges output from an input switching device and a digital-to-analog converter unit, and holding at least two integrated values, a comparator unit for comparing at least the two integrated values output from the integrator unit with a predetermined value. The sigma-delta-type analog-to-digital converter also includes an arithmetic operation unit for operating an output signal of the comparator unit, the arithmetic operation unit being provided with a differential operation unit for computing a difference between at least two comparison signals output from comparator unit.

Sigma-delta type analog-to-digital (AD) converter and angular velocity sensor using same

A magnetic bias filmincludes a magnetic bias magnetthat has magnetic layers and generates a magnetic field within a plane perpendicular to a lamination direction of the magnetic layers, which is manufactured in the shape of substantially a rectangular prism having a long side, a short side, and a thickness (in the lamination direction) in order of decreasing lengths. A ratio of the long side with respect to the short side of the magnetic bias magnetin length is in a range of 5 to 200.

Growing community of inventors

Fukui, Japan

Kouji Nabetani