Hybrid autozeroing and chopping offset cancellation for switched-capacitor circuits
US11012043B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 19, 2019 |
| Grant date | May 18, 2021 |
| Priority date | — |
| Expiry date | Aug 19, 2039 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45724
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A system has an output and receives an input signal. An operational amplifier has an input, an output and an offset at the input. A switched capacitor network samples the input signal at a switched capacitor frequency. An autozeroing capacitor connected to the input of the operational amplifier captures the offset during an offset capture interval according to an autozeroing frequency. Chopping and autozeroing switches, connected between the autozeroing capacitor and the switched capacitor network, chop the sampled input signal according to a chopping frequency and autozero the captured offset according to the autozeroing frequency. De-chopping switches, connected between the output of the operational amplifier and the output of the system, operate on the output of the operational amplifier at the chopping frequency to chop the autozeroed captured offset and de-chop the chopped sampled input signal processed by the operational amplifier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.