PWM-based measurement interface for a micro-machined electrostatic actuator
US6933873B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 29, 2003 |
| Grant date | Aug 23, 2005 |
| Priority date | — |
| Expiry date | Dec 29, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02N1/002
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Methods and apparatus for varying and measuring the position of a micromachined electrostatic actuator using a pulse width modulated (PWM) pulse train are disclosed. One or more voltage pulses are applied to the actuator. In each of the pulses, a voltage changes from a first state to a second state and remains in the second state for a time tpulse before returning to the first state. The position of the actuator may be varied by varying the time Δtpulse. A position of the actuator may be determined by measuring a capacitance of the actuator when the voltage changes state, whether the time t is varied or not. An apparatus for varying the position of a MEMS device may include a pulse width modulation generator coupled to the MEMS device an integrator coupled to the MEMS device and an analog-to-digital converter coupled to the integrator. The integrator may measure a charge transferred during a transition of a pulse from the pulse generator. The integrator may include an amplifier, an integrator capacitor, a hold capacitor, a compensation voltage generator and three switches. The hold capacitor and integrator capacitor may be coupled to a MEMS device. The integrator capacitor, hold ca…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.