Protection arrangement for an audio output channel
US5224169A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 13, 1991 |
| Grant date | Jun 29, 1993 |
| Priority date | — |
| Expiry date | May 13, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/211
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A protection circuit for an audio output channel of a television receiver includes a detector which detects the presence of either or both of (1) a sustained DC component applied to the loudspeaker form the audio power amplifier, (2) and the loss of a supply voltage for the power amplifier. The presence of a of a sustained DC component can damage the loudspeaker. The loss of a supply voltage of the power amplifier can damage the power amplifier and can also result in the application of a sustained DC amplifier and can also result in the application of a sustained DC component to the loudspeaker. For example, the loss of the negative supply voltage of a power amplifier incorporated in an integrated circuit results in the removal of potential from the substrate which otherwise serves to electrically isolates various semiconductor devices supported by the substrate. The detector includes a low pass filter coupled between the output of the power amplifier and inputs of first and second comparators to detect when the output of the low pass filter is within or outside of a "window". A transistor switch is coupled to output of the comparators. As long as the output of the low pass filter …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.