Voltage comparator with automatic output-level adjustment
US5132560A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 28, 1991 |
| Grant date | Jul 21, 1992 |
| Priority date | — |
| Expiry date | Aug 28, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45586
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A differential voltage comparator for driving a digital logic gate includes a differential amplifier stage for receiving V.sub.IN and NOT V.sub.IN input signals, a left voltage level shifter for shifting the output of the left side of the differential amplifier by a predetermined voltage, and a differential current source for the differential amplifier biased on one side by the left voltage level shifter and on its other side by a reference voltage. An output voltage level shifter shifts down the output voltage from the differential comparator by a predetermined amount; and applied the shifted voltage to an output terminal. Transistors in the differential current source are matched to transistors in the digital logic gate being driven for providing an offset in the differential current source; the latter along with equating the shift down voltage of the left voltage level shifter to the sum of the reference voltage and output shift down voltage, ensures that when V.sub.IN is equal to NOT V.sub.IN, the level of the output voltage from the comparator is substantially equal to the logic switching point of the digital logic gate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.