Envelope detection circuit for detection of opening angle of a movable MEMS mirror
Abstract:
An electronic device includes an analog to digital converter receiving an analog mirror sense signal from an oscillating mirror and generating a digital mirror sense signal therefrom, and a digital signal processing block. The digital signal processing block cooperates with the analog to digital converter to take a first sample of the digital mirror sense signal at a first time where a derivative of capacitance of the digital mirror sense signal crosses zero, take a second sample of the digital mirror sense signal at a second time between a peak of the digital mirror sense signal and the first time, and take a third sample of the digital mirror sense signal at a third time after the digital mirror sense signal has reached a minimum. Control circuitry determines an opening angle of the oscillating mirror as a function of the first, second, and third samples.
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