Method and electrical interface circuit enabling multiplexing
US9628906B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 9, 2012 |
| Grant date | Apr 18, 2017 |
| Priority date | — |
| Expiry date | Aug 17, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2410/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electrical interface circuit includes a microphone circuit, a battery charger circuit and an electrical connector for connecting the electrical interface circuit to an external device. The electrical connector has a pin on which signals are multiplexed for connecting either the battery charger circuit to an external supply voltage, or the microphone circuit to an external microphone. The battery charger circuit includes an amplifying circuit for controlling voltage or current to a battery at battery charging, and a p-type power transistor. The pin is connected to the microphone circuit and to a source of the p-type power transistor. When a voltage applied to the pin exceeds the battery voltage, the p-type power transistor provides current from the pin to the charger circuit, and, otherwise, the charger circuit and battery are disconnected from the pin. A method of multiplexing signals on the electrical interface circuit is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.