Voltage comparator with hysteresis
US4710793A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 4, 1985 |
| Grant date | Dec 1, 1987 |
| Priority date | — |
| Expiry date | Sep 4, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K3/2897
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A differential amplifier operated as a voltage comparator includes first and second transistors coupled to first and second inputs respectively of the comparator whereby an applied input signal produces output transitions at an output of the differential amplifier as the input signal passes through and exceeds a first threshold voltage established at the second input of the differential amplifier. A hysteresis producing circuit is coupled to the differential amplifier which is responsive to the applied input signal exceeding the first threshold voltage for establishing a second threshold voltage, which is less than the first threshold voltage, whereby the input signal has to decrease below the value of the first threshold voltage to the second threshold voltage in order for the differential amplifier to switch back to its original operating state wherein hysteresis is established. A P-collector region is provided that is responsive to the second transistor of the differential amplifier being driven into saturation for collecting the saturation current thereof to inhibit this current from being injected into the substrate of the integrated circuit in which the voltage comparator is …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.