AN1941 Datasheet, PDF (1/15 Pages) STMicroelectronics – LOW VOLTAGE LED DRIVER USING

AN1941
APPLICATION NOTE
LOW VOLTAGE LED DRIVER USING
L6920D, L4971 AND L6902D
1 INTRODUCTION
High brightness LEDs are becoming a prominent source of light and often have better efficien-
cy and reliability when compared to that of conventional light sources. While LEDs can oper-
ate from an energy source as simple as a battery and resistor, most applications require an
efficient energy source not only for the reduction of losses, but also for the lumen maintenance
of the LED itself. STMicroelectronics has developed the following non-isolated DC-DC con-
stant current LED driver to aid designers in developing a low cost and efficient platform for driv-
ing high brightness LEDs.
This application note will cover 3 DC-DC power supplies to drive high intensity LEDs.
1 The L6920D boost converter to drive 1 LED for a flash light application
2 The L4971 buck converter to drive 1 to 9 LEDs
3 The L6902D buck converter to drive 1 to 6 LEDs
Figure 1. Reference Design Boards:
L6920D
AN1941/0604
L4971
L6902D
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