STEVAL-ILL027V1 STMicroelectronics

STEVAL-ILL027V1 18 W single stage offline LED driver demonstration board based on the L6562A Data brief Features Input voltage 120 VAC +/-10% Provides 18 W constant power to HBLED Able to drive 14 to 20 HBLED in series Soft switching LED open circuit protection LED short circuit protection Power factor > 0.8 Efficiency > 87% RoHS compliant Description This demonstration board implements a 18 W STEVAL-ILL027V1 non-isolated soft-switched high power factor offline LED driver. The buck-boost converter is chosen for this application due to its simplicity and low cost. The converter operates with constant peak current for constant power control and in transition mode (boundary mode between CCM and DCM) to achieve soft switching. High power factor is achieved by reshaping the peak current nearby the zero crossing of input AC line. May 2009 Doc ID 15711 Rev 1 1/4 For further information contact your local STMicroelectronics sales office. www.st.com 4 Obsolete Product(s) - Obsolete Product(s) Obsolete Product(s) - Obsolete Product(s) Circuit schematic STEVAL-ILL027V1 1 Circuit schematic Figure 1. Schematic diagram --- +++ LEDLEDLEDsss ACACAC +++ R4R4R4 L1L1L1 --- R3R3R3 VccVccVcc ZCDZCDZCD Q1Q1 MULTMULTMULT R2R2R2 INININVVV CCCSSS RRRsss R1R1R1 LLL666562562562AAA AM03804v1 2/4 Doc ID 15711 Rev 1 Obsolete Product(s) - Obsolete Product(s) Obsolete Product(s) - Obsolete Product(s)