LYT3314-3328 LYTSwitch-3 Family Single-Stage LED Driver IC with Combined PFC and Constant Current Output for Outstanding TRIAC Dimming in Isolated and Non-Isolated Topologies Product Highlights Combined Single-Stage PFC + Accurate CC Output Less than 3% CC regulation over line and load L Power Factor >0.9 T Ensures monotonic VA reduction with TRIAC phase angle Low THD, 15% typical for dimmable bulbs, as low as 7% in LYTSwitch-3 BL L D N optimized designs CONTROL BS Advanced Integrated TRIAC Dimmer Detection DS FB BP OC S T Detects leading-edge and trailing-edge TRIAC dimmers High-efficiency mode when no dimmer is present Selectable dimming profile increases design flexibility Fast turn-on (<500 ms) PI-7549a-020316 HLBB Low pop-on and dead-travel Figure 1. Simplified Schematic (Buck). Active bleeder drive for widest dimmer compatibility Design Flexibility Supports buck, buck-boost, tapped buck-boost, boost, isolated and non-isolated flyback Output Power Table Up to 20 W output 1 Output Power Highest Reliability 2 Product No electrolytic bulk capacitors or optoisolators for increased lifetime 85-132 VAC or 185-265 VAC Comprehensive protection features 3 LYT33x4D 5.7 W Input and output overvoltage Output short-circuit and open-loop protection LYT33x5D 8.8 W Advanced thermal control LYT33x6D 12.6 W Thermal foldback ensures that light continues to be delivered at elevated temperatures LYT33x8D 20.4 W End-stop shutdown provides protection during fault conditions Table 1. Output Power Table (Buck Topology). Description Notes: 1. Maximum practical continuous power in an open frame design with adequate The LYTSwitch-3 family is ideal for single-stage power factor heat sinking, measured at 50C ambient (see Key Applications Considerations for more information). corrected constant current LED bulbs and downlighters. 2. Package: D: SO-16B. Each device incorporates a high-voltage power MOSFET and discon- 3. x digit describes V of the integrated switching MOSFET, DSON(MAX) 650 V = 1, 725 V = 2. tinuous 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. Figure 2. SO-16B (D Package). The combination of a low-side switching topology, cooling via electroni- cally 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. The part numbers shown in Table 1 describe 4 different power levels and TM two MOSFET voltage options to cost-optimize designs while EcoSmart switching technology insures maximum efcfi iency for each device size and load condition. www.power.com March 2016 This Product is Covered by Patents and/or Pending Patent Applications.LYT3314-3328 BYPASS DRAIN (BP) (D) REGULATOR 5.25 V UV LINE-SENSE (L) 4.7 V LOV V LOV I LIM I LIM SOA CURRENT LIMIT SOA S Q V I LIM LOV R Q UV DIMMER TYPE V FB AND EDGE + DETECTION V FB(SK) LATCH FAULT ZC PHASE MEASUREMENT V ZC UPDATE CLxx + FREQUENCY AND DUTY CYCLE CONTROL I OOV FEEDBACK (FB) V FB V FB(AR) OUTPUT I FB COMPENSATION (OC) I OUV MULTIPLIER Enable DRIVER CURRENT (EN) SENSING FAULT (DS) AUTO-RESTART HANDLING BLEEDING CURRENT S Q SENSING I - I BS DS (BS) R Q SOURCE (S) V (T) REF BLEEDER CONTROL (BL) PI-7747-020316 Figure 3. Block Diagram. 2 Rev. D 03/16 www.power.com