Patent ID: 8590378

Claim:
A gyroscope sensor circuit for a gyroscope sensor including sensing nodes and driving nodes, the gyroscope sensor circuit comprising: a differential amplifier configured to differentially amplify signals respectively outputted from the sensing nodes of the gyroscope sensor; a phase shifter configured to shift a signal from the differential amplifier by a predetermined shift phase; an amplitude detector configured to detect an amplitude of the signal from the differential amplifier; and a variable gain amplifier configured to amplify the shifted signal from the phase shifter with a gain adjusted depending on the amplitude from the amplitude detector, and provide the amplified signal to the driving nodes of the gyroscope sensor, wherein the amplitude detector is configured to compare a signal generated by filtering the signal from the differential amplifier with a predetermined reference signal, and detect a differential voltage between the compared signals as the amplitude of the signal from the differential amplifier, and the amplitude detector comprises: a first filter configured to pass a signal having a first predetermined band among signals from the differential amplifier; an inverter configured to invert the signal from the first filter; a first comparator configured to generate a switching signal in synchronization with the signal from the first filter; a signal selector configured to select one of the signal from the first filter and the signal from the inverter, depending on the switching signal from the first comparator; a second filter configured to pass a signal having a second predetermined band among signals from the signal selector; and a second comparator configured to compare the signal from the second filter with the predetermined reference signal, detect the differential voltage of the compared signals, and provide the differential voltage to the variable gain amplifier.