Switched capacitor one-bit digital-to-analog converter
US5323158A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 6, 1993 |
| Grant date | Jun 21, 1994 |
| Priority date | — |
| Expiry date | Apr 6, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/464
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A switched capacitor one-bit digital-to-analog converter is preferably utilized in the feedback path of a sigma delta modulator. The one-bit digital-to-analog converter includes first and second capacitors, a first switching circuit for coupling charge from a reference source to the capacitors, and a second switching circuit for coupling charge from the capacitors to positive and negative outputs, such as the summing junction of an operational amplifier. The switches in the second switching circuit have a cross-coupled configuration and are controlled by data dependent control signals. The data dependent control signals are structured such that charge is coupled from the capacitors to the summing junction on both clock phases, regardless of the state of the data. As a result, the sizes of the capacitors can be reduced by a factor of two for the same charge transfer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.