Title :
A > 89% efficient LED driver with 0.5V supply voltage for applications requiring low average current
Author :
Saadeh, Wala ; Tekeste, Temesghen ; Perrott, M.H.
Author_Institution :
Masdar Inst. of Sci. & Technol., Abu Dhabi, United Arab Emirates
Abstract :
A modified boost converter topology is proposed to achieve better than 89% efficiency as an LED driver for applications in which low supply voltage and low average current are desired such as in a photoplethysmographic (PPG) heart rate (HR) monitor device. The approach embraces pulsing of the LED current, and allows a highly digital implementation for varying LED brightness based on Pulse Density Modulation (PDM). Measured results indicate that the LED driver, which is implemented in 180nm CMOS along with an external inductor, achieves an output current range of 28uA to 1.3mA with 6 current settings while maintaining >89% efficiency over a supply voltage range of 0.5 to 0.6V.
Keywords :
CMOS integrated circuits; cardiology; driver circuits; light emitting diodes; network topology; photoplethysmography; power convertors; CMOS; LED driver; PDM; PPG heart rate monitor device; low average current; modified boost converter topology; photoplethysmographic heart rate; pulse density modulation; supply voltage; CMOS integrated circuits; Current measurement; Heart rate; Inductors; Light emitting diodes; MOS devices; Voltage measurement;
Conference_Titel :
Solid-State Circuits Conference (A-SSCC), 2013 IEEE Asian
Conference_Location :
Singapore
Print_ISBN :
978-1-4799-0277-4
DOI :
10.1109/ASSCC.2013.6691035
