Electrostatic MEMS driver with on-chip capacitance measurement for autofocus applications
US8188755B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 2010 |
| Grant date | May 29, 2012 |
| Priority date | — |
| Expiry date | Nov 19, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/2605
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A driver and capacitance measuring circuit includes a voltage source that selectively generates an output voltage at a first node during a driver mode to alter a capacitance of a device that is connected to the first node and that has a variable capacitance. A current source selectively provides one of a charging and discharging current at the first node during a measurement mode. A capacitance calculating circuit samples a voltage at the first node during the measurement node, determines a voltage change rate of the first node during the measurement mode and calculates the capacitance of the device based on the voltage change rate and a value of the one of the charging and discharging current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.