Accurate ninety-degree phase shifter
US8754694B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 2013 |
| Grant date | Jun 17, 2014 |
| Priority date | — |
| Expiry date | Jan 21, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C19/5776
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An apparatus includes a drive signal circuit for MEMS sensor. The drive signal circuit includes an input configured to receive a voltage signal representative of charge generated by the MEMS sensor, a phase-shift circuit electrically coupled to the input and configured to phase shift an input signal by substantially ninety degrees, and a comparator circuit with hysteresis. An input of the comparator is electrically coupled to an output of the phase-shift circuit and an output of the comparator circuit is electrically coupled to an output of the drive signal circuit. A feedback loop extends from the output of the drive signal circuit to the input of the phase-shift circuit and is configured to generate a self-oscillating signal at an output of the drive signal circuit. An output signal generated by the drive signal circuit is applied to a drive input of the MEMS sensor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.