Low power dual power supply high resolution comparator
US5374859A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 30, 1993 |
| Grant date | Dec 20, 1994 |
| Priority date | — |
| Expiry date | Apr 30, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/45076
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A low power comparator is provided in which a wide common mode range, high resolution and near continuous operation is achieved. The comparator of the present invention employs a wide common mode range with true one millivolt resolution. Furthermore, the comparator is a low power device rendering it readily adaptable to today's portable low power devices. An innovative three stage comparator is described. The first stage receives the two input signals to be compared. A number of innovations are utilized to minimize the offsets and therefore errors in the comparison measurements. More particularly, a transmission gate is provided at the inputs to balance the differential amplifiers employed in the first stage. The balance of the differential output nodes permits fast settling time of the comparator and minimizes voltage stresses which can create offsets. Furthermore, the design incorporates fully symmetric loads and is interdigital for optimum matching and minimum size. The second stage circuit utilizes a unique cascode circuit which provides very high gain thereby enabling the comparator to function at a higher resolution. Furthermore, a gain loop is created in the second stage suc…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.