Circuit and method for providing an auto-off and/or auto-on capability for an audio device
US7474757B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 9, 2004 |
| Grant date | Jan 6, 2009 |
| Priority date | — |
| Expiry date | Nov 24, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10H2240/211
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A circuit (FIGS. 2A-2D) and method of providing an auto-on and/or auto-off capability for an audio device, of a type having an audio plug (14) which mates with the output jack of an audio source. The portable transmitter (10) modulates audio signals from the audio source onto a carrier and transmits them to a receiver. The auto-on and auto-off capability is provided to prolong battery life and degradation of the transmitter circuit and comprises pinching off a FET (Q2) when the circuit is in an “off” state. This occurs when a pre-determined threshold in a capacitor is reached by not discharging that capacitor. The capacitor (C29) is discharged by dropping a comparator input below a pre-determined threshold limit when presented with an audio peak and wherein the drop in value causes the comparator output to go low, causing the capacitor to discharge and causing the FET (Q2) to supply power to the regulator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.