The LYTSwitch™-3 family is ideal for single-stage power factor corrected constant current LED bulbs and down lighters. Each device incorporates a high-voltage power MOSFET and discontinuous mode, variable frequency variable on-time controller. The controller also provides cycle-by-cycle current limit, output OVP, line overvoltage, comprehensive protection features, plus advanced thermal management circuitry.
All LYTSwitch-3 ICs have a built-in TRIAC detector that discriminates between leading-edge and trailing-edge dimmers. This capability together with load monitoring circuitry regulates bleeder current during each switching cycle. The controller disables the bleeder circuit completely if no dimmer is detected, significantly increasing efficiency.
The combination of a low-side switching topology, cooling via electronically quiet SOURCE pins and frequency jitter ensure extremely low EMI. This reduces the size of the input filter components-greatly reducing audible noise during dimming.
Combined Single-Stage PFC + Accurate CC Output
Less than ±3% CC regulation over line and load
Power Factor >0.9
Ensures monotonic VA reduction with TRIAC phase angle
Low THD, 15% typical for dimmable bulbs, as low as 7% in optimized designs
Advanced Integrated TRIAC Dimmer Detection
Detects leading-edge and trailing-edge TRIAC dimmers