Patent Number: 8,716,918

Title: Drive circuit and physical quantity measuring device

Abstract: In order for keeping the amplitude of the excitation current of a vibrator constant irrespective not only of the temperature variation but also of the manufacturing variation and the variation in frequency, a comparison control circuit for controlling the amplitude of the drive signal for exciting the vibrator includes a comparative voltage supply circuit for supplying the comparative voltage, and the comparative voltage supply circuit generates the comparative voltage with a constant current source and a second resistor made of a material the same as a material of a first resistor included in a current-voltage conversion circuit.

Inventors: Yamaguchi; Masayuki (Chino, JP)

Assignee: Seiko Epson Corporation

International Classification: H01L 41/08 (20060101)

Expiration Date: 5/06/12018