Electronic device power protection circuitry
US10048715B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 29, 2016 |
| Grant date | Aug 14, 2018 |
| Priority date | — |
| Expiry date | Jul 15, 2036 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W88/02
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A host electronic device may be coupled to an accessory electronic device. During normal operation, the host device may supply the accessory device with power over a power supply line. Back-powering events in which the accessory device delivers power to the host device may be prevented by interposing a protection transistor in the power supply line. A current mirror may be formed using the protection transistor and an additional transistor that produces a sense current proportional to the amount of current that is flowing through the power supply line. A current-to-voltage amplifier may produce a sense voltage that is proportional to the sense current. A bias circuit may be used to bias the sense current through the current mirror. A control circuit may compare the sense voltage to one or more reference voltages and turn off the protection transistor when appropriate to prevent back-powering of the host device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.