Low FPN high gain capacitive transimpedance amplifier for use with capacitive sensors
US6339363B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 4, 2000 |
| Grant date | Jan 15, 2002 |
| Priority date | — |
| Expiry date | Dec 4, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/78
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An amplifier for measuring the charge stored on a source capacitor having a capacitance Cpd. The amplifier includes an opamp having a signal input, reference input and output; the first terminal of the source capacitor is connected to the signal input. The amplifier includes a reset switch for shorting the signal input and the output of the opamp, and a capacitive network. The capacitive network connects the signal input and the output of the opamp, and provides a capacitance of CT between the signal input and the output of the opamp wherein CT<Cpd. The capacitive network is constructed from a plurality of component capacitors. Preferably each component capacitor has a capacitance greater than or equal to Cpd. In one embodiment of the invention, the capacitive network includes first, second, and third component capacitors, each capacitor having first and second terminals. The first terminal of the first capacitor is connected to the output of the opamp; the second terminal of the first capacitor, the first terminal of the second capacitor, and the first terminal of the third capacitor are connected together at a first common node, the second terminal of the third capacitor is conne…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.