Switched-capacitor circuit with scaled reference voltage
US7009549B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 30, 2004 |
| Grant date | Mar 7, 2006 |
| Priority date | — |
| Expiry date | Dec 30, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/442
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A pipelined analog-to-digital converter (ADC) (30) with improved precision is disclosed. The pipelined ADC (30) includes a sequence of stages (20), each of which includes a sample-and-hold circuit (22), an analog-to-digital converter (23), and the functions of a digital-to-analog converter (DAC) (25), an adder (24), and a gain stage (27) at which a residue signal (RES) is generated for application to the next stage (20) in the sequence. A multiplying DAC (28) performs the functions of the DAC (25), adder (24), and gain stage (27) in the stage (20), and is based on an operational amplifier (29). Sample capacitors (C10, C20) and reference capacitors (C122, C222) receive the analog input from the sample-and-hold circuit (22) in a sample phase; parallel capacitors (C121, C221) are provided to maintain constant circuit gain. Extended reference voltages (VREFPX, VREFNX) at levels that exceed the output range (V0+, V0−) of the operational amplifier (29) are applied to the reference capacitors, in response to the digital output of the analog-to-digital converter (23) in its stage (20). The reference capacitors (C12, C22) are scaled according to the extent to which the extended reference vo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.