Signal processing circuit, physical quantity detecting device, and angular speed detecting device

Abstract

The invention provides a signal processing circuit, a physical quantity detecting device, an angular speed detecting device, an integrated circuit device and an electronic device. The increasing of circuit area can be prevented and less noise can be realized. An I / V switching circuit (a current / voltage switching part) converts the oscillation current of an oscillator into voltage. A RC filter (a phase displacement part) conducts a phase displacement on the output signal of the I / V switching circuit. A full-wave rectification circuit (a part of a drive amplitude control part) conducts binaryzation on the signal undergoing the phase displacement, forming a switching control signal. A comparing machine (a reference signal generating part) generates a reference signal for synchronous detection based on the output signal of the I / V switching circuit. An or circuit (a clock signal generating part) generates the clock signal for a switch capacitance filter whose frequency is two times as that of a drive signal, based on the phase difference between the reference signal and the switching control signal.

Description

technical field [0001] The present invention relates to a signal processing circuit, a physical quantity detection device, an angular velocity detection device, an integrated circuit device and electronic equipment. Background technique [0002] Gyro sensors are installed in various electronic devices such as digital cameras, navigation devices, and mobile phones. Based on the magnitude of the angular velocity detected by the gyro sensor, processing such as shake correction, dead reckoning, and interactive sensing is performed. [0003] In recent years, miniaturization and high detection accuracy of gyro sensors are required, and as gyro sensors satisfying these requirements, for example, vibrating gyro sensors using the resonance phenomenon of quartz resonators are widely used. In the case of using such a vibrating gyro sensor, since the detection signal output from the vibrator becomes smaller due to miniaturization, in order to achieve high detection accuracy, the signal ...

AI Technical Summary

Problems solved by technology

[0007] However, due to the sampling of the SCF, f d 、2f d 、3f d , ... and other frequency bands will fold back to the DC band, so the noise in these frequency bands will be superimposed on the detection signal

In the past, the noise generated in the SCF was relatively small and could be ignored. However, when it is desired to achieve lower noise, the noise generated in the SCF cannot be ignored.

By increasing the sampling frequency of the SCF, the amount of noise folded back to the DC band can be reduced. However, since there is generally no signal with a frequency higher than the drive frequency of the vibrator in the signal processing circuit, it is necessary to add a new signal with a frequency higher than the drive frequency. signal circuit

By adding a multiplier circuit such as a PLL (Phase Locked Loop: Phase Locked Loop circuit), although it is possible to generate a signal with a multiplied frequency of the driving frequency, the circuit area is greatly increased, which is contrary to the demand for miniaturization.

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