Tristate changeover switching circuit
US4203043A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 5, 1978 |
| Grant date | May 13, 1980 |
| Priority date | — |
| Expiry date | May 5, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K5/08
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A switching circuit having a current source connected to first, second and third lines in order to supply first and second current signals whose total amount remains constant to the first and second current lines, respectively. The current source further supplies a constant bias I.sub.B to the third line. First and second diode pairs are respectively connected in parallel in opposite directions between the first and third signal current lines, and between the second and third signal lines, respectively. First and second transistors are connected to the three signal current lines, respectively, with the base voltages of these transistors kept constant at the same voltage level. Accordingly, current passing through the first and second diode pairs change flow direction in accordance with the incremental variations of current flowing in the first and second lines. As a result, the output voltages at the collectors of the first and second transistors represent any of the three prescribed states in accordance with the extent of the incremental current variation in the first and second lines.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.