Integrated circuit having a filter with charge balancing scheme to reduce transient disturbances
US6400217B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 22, 1999 |
| Grant date | Jun 4, 2002 |
| Priority date | — |
| Expiry date | Dec 22, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45726
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An integrated circuit includes a filter with switched capacitors to dynamically adjust a corner frequency of the filter. Such dynamically adjustable filters are typically included in circuits to reduce noise, and consequently such filters should not themselves generate noise. An equalization circuit is included in the filter to equalize the potential on each terminal of the switched capacitors prior to being switched into circuit, thereby removing a source of transient current. Another source of noise is a transient current induced by the application of control signals to the transistors used to switch the capacitors into circuit. A compensation circuit is included which generates a compensation current of opposite sense and substantially the same magnitude as the induced transient currents, to thereby effectively cancel noise at the filter output.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.