公开(公告)号：US10694603B1

公开(公告)日：2020-06-23

申请号：US16684567

申请日：2019-11-14

Applicant: Apple Inc.

Inventor： Cristian Grecu ,  Bogdan-Eugen Matei ,  Angelo Bassi ,  Andrei-Cosmin Gaidam ,  Alessandro Molari

IPC: H05B45/10 ,  H05B45/37 ,  H05B45/44

Abstract: An LED driver circuit is disclosed. The LED driver circuit includes an amplifier having a first input coupled to receive a reference voltage and a second input coupled to receive a feedback voltage. The circuit further includes first and second transistors each having respective gate terminals coupled to an output of the first amplifier. In a first mode, a first switch alternately couples a source terminal of the first transistor to the second input of the amplifier (when the pulse is asserted) and a source terminal of the second transistor to the second input (when the pulse is de-asserted). A third transistor includes a gate terminal that is coupled to ground, by a second switch, when operating in the first mode. When operating in the second mode, the switch couples the third transistor to the output of the amplifier, while the pulse remains asserted.