Switch with frequency compensation, differential bias operation compensation and enable indicator
US5212414A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 26, 1990 |
| Grant date | May 18, 1993 |
| Priority date | — |
| Expiry date | Sep 26, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/18
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The switch has a cross-point. The cross-point has an input buffer, a level shift and an output buffer. The input and output buffers are BJT's, the level shift is two diode connected BJT's. The voltage drops across the buffers are designed to match the voltage drops across the diodes. The cross-point is enabled by a current source forcing current through the diodes. The matching of the voltage drops is effected by the Early voltage of the BJT's as they are operated at different V.sub.ce 's. An Early voltage determinator determines the effect of the Early voltage and adjusts the current flowing from the current source to force differing bias currents through the input buffer and the diodes to make the sum of the V.sub.be 's of each more independent of Early voltage. The output impedance of the current source and the impedance of the cross-point form a resistor-capacitor network. Where the f.sub..tau. of the current source is sufficiently low, the network has a pole-zero combination within the otherwise usable bandwidth of the switch. The current source has a first BJT at its output. A frequency compensating BJT is connected to the base of the first BJT, bringing the pole and zero clo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.