Title :
A dimmable LED driver with an ambient light sensor based on a constant off-time control technique
Author :
Yuan-Ta Hsieh ; Jian-Fu Wu ; Chiao-Li Fang ; Hann-Huei Tsai ; Ying-Zong Juang ; Bin-Da Liu
Author_Institution :
Nat. Chip Implementation Center, Hsinchu, Taiwan
Abstract :
This paper presents an asynchronous boost-type light-emitting diode (LED) driver, integrating an ambient light sensor (ALS), based on a constant off-time control technique. The LED driver automatically regulates the LED current according to the surrounding illumination as sensed by the on-chip ALS. In backlighting applications, the brightness of the light source is adjusted inversely; therefore, we enabled the selection of two modes of operation: illumination and backlighting. The proposed design is capable of reducing power dissipation for both illumination and backlighting applications. For verification, a prototype was fabricated using the TSMC 0.25-μm 60-V bipolar-CMOS-DMOS process with a chip size of 1900μm × 1330μm.
Keywords :
BIMOS integrated circuits; driver circuits; electric current control; light emitting diodes; optical sensors; LED current regulation; TSMC bipolar-CMOS-DMOS process; ambient light sensor; asynchronous boost-type light-emitting diode driver; backlighting; constant off-time control technique; dimmable LED driver; on-chip ALS; power dissipation reduction; size 0.25 mum; surrounding illumination; voltage 60 V; Brightness; Light emitting diodes; Lighting; Photodiodes; Power dissipation; Switches; System-on-a-chip; Dimmable LED driver; constant off-time control; on-chip ambient light sensor;
Conference_Titel :
Electrical Machines and Systems (ICEMS), 2012 15th International Conference on
Print_ISBN :
978-1-4673-2327-7
