Protective circuit
US4276442A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 1979 |
| Grant date | Jun 30, 1981 |
| Priority date | — |
| Expiry date | Mar 29, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F1/52
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The output derived from an electric circuit such as an OCL type power amplifier circuit is delivered to a load such as a speaker, through a switching means such as a relay. When the operation of the electric circuit has come out of a predetermined range of operation, the switching means is operated to break the connection between the electric circuit and the load. A detection circuit for detecting the operation of the electric circuit includes a detecting transistor constructed in a semiconductor integrated circuit. The detecting transistor is connected at its base to the input terminal for external connection of the semiconductor integrated circuit, so as to receive a signal representative of the operation state of the electric circuit. The detecting transistor is so biased as to allow a predetermined electric current to flow therethrough, when the electric circuit is operating within the predetermined range of operation. However, in case of a breakdown of the detecting transistor, or when the operation of the electric circuit has come out of the predetermined range of operation, the current flowing through the detecting transistor is changed from the predetermined level. This cha…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.