Electronic compensation of capacitive micro-machined sensors parasitic modes in force-feedback interface systems
US8872683B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 26, 2014 |
| Grant date | Oct 28, 2014 |
| Priority date | — |
| Expiry date | Feb 26, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/43
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Operating capacitive sensors in force feedback mode has many benefits, such as improved bandwidth, and lower sensitivity to process and temperature variation. To overcome, the non-linearity of the voltage-to-force relation in capacitive feedback, a two-level feedback signal is often used. Therefore, a single-bit Σ-Δ modulator represents a practical way to implement capacitive sensors interface circuits. However, high-Q parasitic modes that exist in high-Q sensors (operating in vacuum) cause a stability problem for the Σ-Δ loop, and hence, limit the applicability of Σ-Δ technique to such sensors. A solution is provided that allows stabilizing the Σ-Δ loop, in the presence of high-Q parasitic modes. The solution is applicable to low or high order Σ-Δ based interfaces for capacitive sensors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.