公开(公告)号：US09820343B1

公开(公告)日：2017-11-14

申请号：US15219150

申请日：2016-07-25

Applicant: Infineon Technologies AG

Inventor： Fabio Fragiacomo ,  Maurizio Galvano ,  Hardy Stoelben

IPC: H05B33/08 ,  B60Q1/04

CPC classification number: H05B33/0809 ,  B60Q1/04 ,  H05B33/0815 ,  H05B33/083

Abstract: A driver circuit for light-emitting diode (LED) headlight system includes a buck-boost converter connected in series to a first plurality of branches of LEDs. Each of the plurality of branches of LEDs includes a bypass switch configured to bypass the corresponding branch of LEDs. The buck-boost converter provides a constant current with an adjustable voltage to a selectable portion of the plurality of branches of LEDs, while bypassing each of the other branches of LEDs via the corresponding bypass switches. In some examples, the circuit delivers the current to the selectable portion of the first plurality of branches of LEDs during a first portion of a duty cycle, while delivering a digitally modulated current to a second plurality of branches during a second portion of the duty cycle.