Digital-to-analog converter, analog-to-digital converter, and semiconductor device
US7936294B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 2009 |
| Grant date | May 3, 2011 |
| Priority date | — |
| Expiry date | Apr 20, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/747
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A DA conversion device includes the following elements. A higher-bit current source cell portion includes uniformly weighted higher-bit current source cells to generate an identical constant current. A lower-bit current source cell portion includes a lower-bit current source cells that are weighted to generate 1/two-to-the-power-of-certain-numbers constant currents. A constant current source selection controller includes a lower-bit controller having a scaler that uses clocks scaled down to 1/two-to-the-power-of-certain-numbers to select the lower-bit current source cells, and a higher-bit controller having shift registers and using a signal indicating a carry bit or a borrow bit used in the lower-bit controller to sequentially activate shift outputs of the shift registers, and uses the shift outputs to select the higher-bit current source cells. Constant current outputs of the selected current source cells are added and output so that an output current corresponding to the digital input signal is obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.