Current switch logic circuit with controlled output signal levels
US4894562A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 1988 |
| Grant date | Jan 16, 1990 |
| Priority date | — |
| Expiry date | Oct 3, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/00376
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A current switch emitter-follower logic circuit allows both the UP output logic level and the DOWN output logic level to be independently controlled with respect to a fixed reference voltage so as to permit very small output level swings. A feedback circuit generates two different control signals which are independently variable and are input to a control circuit and to a logic circuit to compensate for fluctuations in power supply voltages, temperature and circuit parameters. These control signals are applied to a variable current source within the logic circuit and to a dynamic resistance within the control circuit to compensate almost instantaneously to fluctuations in power supply voltage, temperature or circuit device parameters, maintaining the logic circuit output levels close to reference levels so as to permit small output signal swings. The output logic levels need not be symmetrical around a central reference point.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.