公开(公告)号：US20180070415A1

公开(公告)日：2018-03-08

申请号：US15698848

申请日：2017-09-08

Applicant: SAMSUNG ELECTRONICS CO., LTD.

Inventor： Sung Yong JOO ,  Jin Hyung LEE ,  Moon Young KIM

IPC: H05B33/08 ,  G09G3/34 ,  G09G3/36

CPC classification number: H05B33/083 ,  G09G3/3406 ,  G09G3/342 ,  G09G3/36 ,  G09G2320/0204 ,  G09G2320/0247 ,  G09G2320/0626 ,  G09G2320/064 ,  G09G2320/0693 ,  G09G2330/025 ,  H05B33/0815 ,  H05B33/0827 ,  H05B33/0845

Abstract: A back light device includes a first light emitting block including a plurality of light emitting modules connected in series to each other; a power supply module that applies a driving voltage to the first light emitting block; a first power switch connected to the first light emitting block and controls the driving voltage on or off; and a control module that turns on or off the first power switch such that a constant current is supplied to the first light emitting block and controls an on/off of the plurality of light emitting modules based on a dimming signal. The control module, in response to a ripple value of the constant current being different from a certain ripple value, changes at least one of a turn-on period and a turn-off period of the first power switch to calibrate the ripple value of the constant current to the certain ripple value.