Intrinsically safe logic and-circuit having two inputs
US5357151A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 29, 1993 |
| Grant date | Oct 18, 1994 |
| Priority date | — |
| Expiry date | Jun 29, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/007
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A logic AND circuit comprises, in a cascade arrangement, a threshold oscillator having a power supply input connected to a first circuit input and a clamping amplifier providing an output signal only when simultaneously the voltage on a second circuit input exceeds a threshold and the threshold oscillator delivers an output signal. The oscillator comprises a single transistor whose emitter and collector circuits contain two primary windings of a transformer whose secondary winding constitutes a tuned circuit in association with a four-lead capacitor and whose base is biased from the first input via a filter cell having a parallel-connected four-lead capacitor. The clamping amplifier includes a single transistor connected to the second input via a filter cell having a parallel-connected four-lead capacitor, with one of its emitter and collector circuits containing the primary winding of another transformer whose secondary winding contains a resonant circuit with a parallel-connected four-lead capacitor from whose terminals an alternating output signal is taken.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.