Audio loudspeaker detection using back-EMF sensing
US6870934B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 2002 |
| Grant date | Mar 22, 2005 |
| Priority date | — |
| Expiry date | Oct 21, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2420/05
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The presence or absence of a speaker connected to an output terminal of an audio system is determined based on the electro-generator properties of the speaker. The audio system includes an output amplifier coupled to the output terminal. The method includes driving the output amplifier with a predetermined drive signal sufficient to produce a predetermined speaker excursion if a speaker is connected to the output terminal. The output amplifier is then isolated from the output terminal. A signal at the output terminal is sensed after the output amplifier is isolated. The sensed signal is compared with a predetermined reference for determining whether a speaker back-EMF is present. A speaker detection signal is generated indicating absence of a speaker if the back-EMF is not present.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.