Resistor self-trim circuit for increased performance
US7642852B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 2008 |
| Grant date | Jan 5, 2010 |
| Priority date | — |
| Expiry date | Jul 15, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45702
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
In a method and apparatus for trimming values of load resistors to reduce variations there between, a common mode feedback loop (CMFBL) included in a differential amplifier is switched from operating in a closed loop mode to operate in an open loop mode. The CMFBL includes an operational amplifier (OA) generating an output signal. A selector switch, coupled to receive the output signal, is operable to switch a path of the output signal in response to a CAL signal. In the closed loop mode, the selector switch routes the output signal to a feedback loop to provide a regulated current to the load resistors. In the open loop mode, the OA operates as a comparator and the output signal is provided as a digital signal. The selector switch provides the digital signal to a controller to digitally trim the values of the load resistors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.