Device for protecting an electrical circuit against interference pulses
US4977340A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 23, 1988 |
| Grant date | Dec 11, 1990 |
| Priority date | — |
| Expiry date | Nov 23, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/00353
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A protection device for suppressing higher frequency interference pulses in an input signal for an electric circuit includes a transistor whose emitter is grounded via a current source to act as an emitter follower for an input signal. The voltage drop of the base-emitter diode of the transistor is compensated for by a corresponding voltage drop across a diode whose anode is connected to a voltage supply line via a second current source. A junction point of the second current source and the diode is connected to a capacitor which together with the second current source forms a low-pass member for the input signal. A Schmitt-trigger circuit is connected to the junction point to restore lower frequency input pulses from trapezoidal pulses picked up at the capacitor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.