Abstract: A physical quantity detection circuit (12) is used for a physical quantity sensor (10) that outputs a sensor signal according to a physical quantity given externally. In the physical quantity detection circuit (12), an analog-to-digital converter (104) converts an analog sensor signal (Ssnc) to a digital sensor signal (Dsnc). A digital filter (100) attenuates a frequency component of the digital sensor signal (Dsnc) that is higher than a predetermined cutoff frequency. A multiplier (106) multiplies a digital sensor signal (Dps) having passed the digital filter (100) by a digital detection signal (Ddet) to detect a digital physical quantity signal (Dphy).

Abstract: A physical quantity detection circuit (12) is used for a physical quantity sensor (10) that outputs a sensor signal according to a physical quantity given externally. A sampling phase adjustment circuit (100) adjusts the phase of a sampling clock (CKa). An analog-to-digital converter circuit (104) converts the sensor signal (Ssnc) to a digital sensor signal (Dsnc) in synchronization with the sampling clock (CKsp) phase-adjusted by the sampling phase adjustment circuit. A detection circuit (107) detects the physical quantity based on the digital sensor signal (Dsnc) from the analog-to-digital converter circuit.

Abstract: A physical quantity detection circuit (12) is used for a physical quantity sensor (10) that outputs a sensor signal according to a physical quantity given externally. A phase adjustment circuit (100) receives a reference clock (CKref) and operates in synchronization with an operation clock (CKa), to delay a transition edge of the reference clock by a predetermined number of pulses of the operation clock. A detection circuit (104) detects a physical quantity signal from the sensor signal (Ssnc) using a transition edge of a clock (SSS) from the phase adjustment circuit (100) as the reference.

Abstract: An amplitude detection circuit detects the amplitude value of a monitor signal responsive to self-excited vibration of a physical quantity sensor. A waveform shaping circuit converts the monitor signal to a pulse signal. A pulse amplitude modulation circuit adjusts the amplitude of the pulse signal according to the amplitude value obtained by the amplitude detection circuit and outputs the result as a drive signal for control of the self-excited vibration of the physical quantity sensor.

Abstract: A physical quantity sensor system drives a physical quantity sensor and detects a physical quantity signal from a sensor signal. An analog-to-digital conversion circuit respectively converts a monitor signal and the sensor signal to a digital monitor signal and a digital sensor signal. A drive control circuit controls a drive signal according to the digital monitor signal. A phase adjustment circuit adjusts the phase difference between the digital monitor signal and the digital sensor signal. A detection circuit detects the physical quantity signal by multiplying the digital monitor signal by the digital sensor signal after the phase difference adjustment by the phase adjustment circuit.

Abstract: A physical quantity detection circuit (12) is used for a physical quantity sensor (10) that outputs a sensor signal according to a physical quantity given externally. In the physical quantity detection circuit (12), an analog-to-digital converter (104) converts an analog sensor signal (Ssnc) to a digital sensor signal (Dsnc). A digital filter (100) attenuates a frequency component of the digital sensor signal (Dsnc) that is higher than a predetermined cutoff frequency. A multiplier (106) multiplies a digital sensor signal (Dps) having passed the digital filter (100) by a digital detection signal (Ddet) to detect a digital physical quantity signal (Dphy).

Abstract: A switched capacitor has a differential amplifier and a sampling capacitance and a feedback capacitance at least one of which has a variable capacitance value, and is switchable between a first drive mode of amplifying an input signal with a positive gain responsive to the capacitance ratio of the sampling capacitance to the feedback capacitance and a second drive mode of amplifying the input signal with a negative gain responsive to the capacitance ratio. A control circuit changes the capacitance ratio, and also changes the drive mode of the switched capacitor, at predetermined timing.

Abstract: A physical quantity detection circuit (12) is used for a physical quantity sensor (10) that outputs a sensor signal according to a physical quantity given externally. A phase adjustment circuit (100) receives a reference clock (CKref) and operates in synchronization with an operation clock (CKa), to delay a transition edge of the reference clock by a predetermined number of pulses of the operation clock. A detection circuit (104) detects a physical quantity signal from the sensor signal (Ssnc) using a transition edge of a clock (SSS) from the phase adjustment circuit (100) as the reference.

Abstract: A physical quantity detection circuit (12) is used for a physical quantity sensor (10) that outputs a sensor signal according to a physical quantity given externally. A sampling phase adjustment circuit (100) adjusts the phase of a sampling clock (CKa). An analog-to-digital converter circuit (104) converts the sensor signal (Ssnc) to a digital sensor signal (Dsnc) in synchronization with the sampling clock (CKsp) phase-adjusted by the sampling phase adjustment circuit. A detection circuit (107) detects the physical quantity based on the digital sensor signal (Dsnc) from the analog-to-digital converter circuit.