Issued Patents All Time
Showing 1–16 of 16 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5812658 | Method and circuit for failsafe switch-hook detection during fault in a telephone system | Donald K. Whitney | 1998-09-22 |
| 5671272 | Current mode ring trip detector | — | 1997-09-23 |
| 5659570 | Circuit and method for loopback test and on-hook transmission integrated in a telephone subscriber line interface circuit | Christopher Ludeman, Donald K. Whitney | 1997-08-19 |
| 5614867 | Current follower with zero input impedance | — | 1997-03-25 |
| 5572162 | Filter with reduced element ratings and method | — | 1996-11-05 |
| 5517565 | Integrated ringer relay circuit and method | — | 1996-05-14 |
| 5515417 | Ground key detector for a SLIC | — | 1996-05-07 |
| 5515434 | Impedance setting circuit for a SLIC | — | 1996-05-07 |
| 5471131 | Analog-to-digital converter and reference voltage circuitry | Ken King, David W. Riemer | 1995-11-28 |
| 5382916 | Differential voltage follower | Ken King, David W. Riemer | 1995-01-17 |
| 4891604 | High speed low input current voltage follower stage | — | 1990-01-02 |
| 4879520 | High accuracy current source and high accuracy transconductance stage | — | 1989-11-07 |
| 4879523 | High accuracy, high impedance differential to single-ended current converter | — | 1989-11-07 |
| 4783637 | Front end stage of an operational amplifier | — | 1988-11-08 |
| 4636743 | Front end stage of an operational amplifier | — | 1987-01-13 |
| 4560948 | Circuit for increasing voltage gain | John S. Prentice | 1985-12-24 |