LED driver ICs suit industrial lighting applications

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.

Key benefits:

• 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).