A tuning fork sensor system places a controlled bias on the proof-mass drive-axis electrodes to cancel the quadrature charge. Also, its charge amplifiers employ a field-effect transistor biased slightly into the triode region so that it behaves as a very large value resistor. In addition, it uses a phase-locked loop having a special loop filter in order to optimize performance by rejecting off-frequency drive feedthrough to the motor pick-off while resulting in very low phase wander for the demodulation references.

A tuning fork sensor system places a controlled bias on the proof-mass drive-axis electrodes to cancel the quadrature charge. Also, its charge amplifiers employ a field-effect transistor biased slightly into the triode region so that it behaves as a very large value resistor. In addition, it uses a phase-locked loop having a special loop filter in order to optimize performance by rejecting off-frequency drive feedthrough to the motor pick-off while resulting in very low phase wander for the demodulation references.

A physical quantity detection circuit includes a signal conversion circuit configured to output a first differential signal based on an output signal of a physical quantity detection element, an active filter to which a second differential signal based on the first differential signal is input, and an analog/digital conversion circuit configured to sample a third differential signal based on an output signal of the active filter to convert the third differential signal into a digital signal, wherein the active filter includes an operational amplifier, a first chopping circuit disposed in a signal path between the signal conversion circuit and the operational amplifier, and a second chopping circuit disposed in a signal path between the operational amplifier and the analog/digital conversion circuit, and fch<fs/2, the sampling frequency is fs, and the chopping frequency is fch.

A physical quantity detection circuit includes a signal conversion circuit configured to output a first differential signal based on an output signal of a physical quantity detection element, an active filter to which a second differential signal based on the first differential signal is input, and an analog/digital conversion circuit configured to sample a third differential signal based on an output signal of the active filter to convert the third differential signal into a digital signal, wherein the active filter includes an operational amplifier, a first chopping circuit disposed in a signal path between the signal conversion circuit and the operational amplifier, and a second chopping circuit disposed in a signal path between the operational amplifier and the analog/digital conversion circuit, and fch<fs/2, the sampling frequency is fs, and the chopping frequency is fch.

A method includes receiving a signal from a sensor. The signal includes a first in-phase component and a first quadrature component. The first in-phase and quadrature components are identified. A rate signal is applied to the sensor and the sensor generates a sensed rate signal. A second in-phase and quadrature components associated with the sensed rate signal are determined. A phase error based on the first and the second in-phase components, and the first and the second quadrature components is determined. The method may further include reducing error in measurements associated with the sensor by dynamically compensating for the determined phase error, e.g., by modifying a clock signal, by changing a demodulation phase of a demodulator used to identify the in-phase and the quadrature components.

A system and/or method for efficiently operating a MEMS gyroscope without drive circuitry and/or with drive circuitry and a non-constant oscillating amplitude. In a non-limiting example, drive circuitry may be utilized to drive the MEMS gyroscope proof mass to a desired oscillating amplitude, and then the drive circuitry may be powered off. Rotational velocity may be sensed while the proof mass is being driven to a desired oscillating amplitude, while the proof mass is being maintained at a desired oscillating amplitude, and/or while the proof mass amplitude decays.

A system and/or method for efficiently operating a MEMS gyroscope without drive circuitry and/or with drive circuitry and a non-constant oscillating amplitude. In a non-limiting example, drive circuitry may be utilized to drive the MEMS gyroscope proof mass to a desired oscillating amplitude, and then the drive circuitry may be powered off. Rotational velocity may be sensed while the proof mass is being driven to a desired oscillating amplitude, while the proof mass is being maintained at a desired oscillating amplitude, and/or while the proof mass amplitude decays.

A detection device includes: a drive circuit which receives a feedback signal from a physical quantity transducer and drives the physical quantity transducer; a detection circuit which receives a detection signal from the physical quantity transducer and detects a desired signal; and a control unit which controls switching on/off of an AGC loop in the drive circuit. The drive circuit outputs a drive signal based on a control voltage that is set by the AGC loop in an on-period of the AGC loop to the physical quantity transducer and thus drives the physical quantity transducer in an off-period of the AGC loop.

A detection device includes: a drive circuit which receives a feedback signal from a physical quantity transducer and drives the physical quantity transducer; a detection circuit which receives a detection signal from the physical quantity transducer and detects a desired signal; and a control unit which controls switching on/off of an AGC loop in the drive circuit. The drive circuit outputs a drive signal based on a control voltage that is set by the AGC loop in an on-period of the AGC loop to the physical quantity transducer and thus drives the physical quantity transducer in an off-period of the AGC loop.

Facilitating minimization of non-linearity effects of a delay of a capacitance-to-voltage (C2V) converter on an output of a gyroscope is presented herein. A sense output signal of a sense mass of the gyroscope and a drive output signal of a drive mass of the gyroscope are electronically coupled to respective analog-to-digital converter (ADC) inputs of bandpass sigma-delta ADCs of the gyroscope. The bandpass sigma-delta ADCs include respective C2V converters that are electronically coupled, via respective feedback loops, to the respective ADC inputs to facilitate reductions of respective propagation delays of the bandpass sigma-delta ADCs. Respective ADC outputs of the bandpass sigma-delta ADCs are electronically coupled to demodulator inputs of a demodulator of the gyroscope that transforms the sense output into an output of the MEMS gyroscope representing an external stimulus that has been applied to the sense mass.