iWatt has expanded its family of digital LED driver ICs with its first power-factor-corrected (PFC) ac-dc Digital PWM Controller targeting 120 V/230 Vac offline commercial and industrial LED lighting applications.
Like its iW3602 and iW3612 siblings, the new iW3614 (3 to 15 W) is designed for LED drivers used in space-constrained incandescent replacement lamps, offers hot-plug support and flicker-free compatibility with existing wall dimmers, and incorporates features to assure power efficiency, durability, and reduced size and component costs.
As iWatt’s first PFC LED driver IC, the iW3614 features a two-stage PFC scheme on a single chip. A front-stage boost converter enables PF > 0.90 (typically 0.94), while the following PWM driver stage minimizes ripple current at the output.
- Eliminating the low 100/120Hz line frequency ripple and resulting flicker at the output eliminates the health concerns (migraines, eye strain, etc.) that are currently under scrutiny by the IEEE PAR1789.
- Reducing the output ripple current enables smaller output capacitors.
- A small bulk storage capacitor enables a wide (1% to 100%) dimming range, while single-stage designs can limit the range (~ 10% to 100%) without that storage capacitor to power LEDs when the dimmer phase cut is low.
- Digital control, primary side control, quasi-resonant switching, and high switching frequency combine to reduce thermal loss, component count, driver size, and bill of materials (BOM).
For more information, contact iWatt Inc., 101 Albright Way, Los Gatos, CA 95032. Phone: (408) 374-4200.