Invention Grant
- Patent Title: Electronic device power protection circuitry
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Application No.: US15143321Application Date: 2016-04-29
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Publication No.: US10048715B2Publication Date: 2018-08-14
- Inventor: Rajarshi Paul , Yehonatan Perez , Stephen J. Hrinya , Eugene L. Shoykhet
- Applicant: Apple Inc.
- Applicant Address: US CA Cupertino
- Assignee: Apple Inc.
- Current Assignee: Apple Inc.
- Current Assignee Address: US CA Cupertino
- Agency: Treyz Law Group, P.C.
- Agent G. Victor Treyz; Vineet Dixit
- Main IPC: G05F3/02
- IPC: G05F3/02 ; G06F3/02 ; H02H3/18 ; H02H7/20 ; H04W88/02 ; H02H9/02

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.
Public/Granted literature
- US20160320788A1 Electronic Device Power Protection Circuitry Public/Granted day:2016-11-03
Information query
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