Directly-writable digital potentiometer
US5297056A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1990 |
| Grant date | Mar 22, 1994 |
| Priority date | — |
| Expiry date | Mar 30, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/765
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A digital potentiometer, in which the three terminals of the potentiometer are all free-floating. The position of the wiper is selected by a control signal received on a serial port. A change is made in the effective position of the wiper until the reset-bar signal goes low. Thus, the value of the potentiometer can be directly changed to any desired value, without intermediate incrementing steps. Moreover, this control arrangement allows multiple such potentiometers to share the same serial control bus, in a "daisy chain" configuration. This has the advantage that all of the potentiometers on the serial control bus will change their values at the same time. (This is advantageous, for example, in systems where such potentiometers are used to set the gain characteristics of multiple op amps. Since all potentiometers are switched at the same time, the system can be forced to go from one stable state to another stable state, with no risk of undesirable intermediate state being brought on by increment/decrement operations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.