Fast capacitance measurement
US6191723A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 22, 1999 |
| Grant date | Feb 20, 2001 |
| Priority date | — |
| Expiry date | Jul 22, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/2605
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of measuring capacitance is provided in which measurement speed is increased by as much as two orders of magnitude by optimizing timing parameters to rapidly charge and discharge the capacitor in small increments about an equilibrium voltage. The capacitor is charged at a linear rate by applying a predetermined constant current thereto, and discharged at an exponential rate determined by the RC time constant in the discharge path. Incremental charge and discharge times are selected in such a manner that results in an equilibrium voltage at a point where the charge voltage ramp and discharge voltage curve would cross if they were superimposed on one another. By appropriate selection of the incremental charge and discharge times, the equilibrium voltage may be conveniently established at a point well within the range of a measuring analog-to-digital converter (ADC). The voltage difference over the incremental charge time may be measured on one cycle and utilized to compute the capacitance value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.