LYT7503-7504 LYTSwitch-7 Family Phase-Cut Dimmable Single-Stage LED Driver IC with Combined PFC and Constant Current Output for Buck Topology Product Highlights Single-Stage PFC + Accurate CC Output 3% CC regulation in single line input voltage applications Power factor >0.9 High efficiency >85% Robust 725 V MOSFET for increased line voltage surge resistance Critical Conduction Mode (CrM) buck LYTSwitch-7 Low EMI BP FB Excellent line noise and transient rejection S D Dimming Highlights M PI-8010-071116 Fast turn-on (<500 ms) Low pop-on Figure 1. Buck Typical Application Schematic. Better than 10:1 dimming ratio Simple passive R-C damper Monotonic dimming profile 25 115 LYT7504D 230 Design Flexibility Wide input (90 VAC 308 VAC) and output voltage range operation 20 2 family members cover power range for optimum device selection Requires no inductor bias winding Small form factor package SO-8 15 Highest Reliability Industrys lowest component count dimming solution 10 Comprehensive protection features with auto-restart Input and output overvoltage protection (OVP) Output short-circuit protection 5 Open-loop protection Advanced thermal control Thermal foldback ensures that light continues to be delivered at 0 elevated temperatures 20 30 40 50 60 70 80 90 100 Over-temperature shutdown provides protection during fault V (V) OUT conditions 25 115 Description LYT7503D 230 The LYTSwitch-7 family is ideal for single-stage, high PF, constant 20 current LED dimmable applications. The family incorporates a high-voltage MOSFET with a variable on-time CrM controller. Extensive protection features with minimum external 15 components provide industry leading power density and functionality. The CrM operation results in low turn-on losses and reduces cost of 10 output diode (slower reverse-recovery type can be used). LYTSwitch-7 devices are suitable for applications from 4 W to 22 W. 5 See Graph 1 for selection guidance (based on typical inductance). For more information, see Application section. LYTSwitch-7 peak current mode operation is suitable for TRIAC applications without the need for 0 an active bleeder. 20 30 40 50 60 70 80 90 100 V (V) OUT (1,2) Graph 1. Output Power Graph (Buck Topology). Notes: 1. Maximum practical continuous power in an open frame design with adequate heat sinking, measured at 50C ambient. 2. Output power graph based on typical values for inductance, I , T LIMIT(AR) ON(MAX) and package thermal limits. Figure 2. SO-8 D Package. www.power.com July 2016 This Product is Covered by Patents and/or Pending Patent Applications. Power (W) Power (W) PI-8009-071116 PI-8009a-071116LYT7503-7504 DRAIN (D) BYPASS (BP) IOVP I REGULATOR LIMIT INPUT SOA 5.25 V LINE Line Comp SENSE THERMAL OTP SHUTDOWN MULTI- FUNCTION (M) ZERO CURRENT DETECTION SOURCE OOVP (S) V OUT VOUT SS SENSE FAULT FAULT HANDLING UV 4.5 V SYSTEM CLOCK I VALLEY AC High 0.7 V FB(REF) T ON CONTROL UP/DN S Q STATE R1 LOGIC COUNTER MACHINE 0 V I PK AC Valley R Q R2 FEEDBACK (FB) PI-7907-071316 Figure 3. Block Diagram. Pin Functional Description BYPASS (BP) Pin: 5.25 V supply rail. D Package (SO-8) MULTIFUNCTION (M) Pin: 1 8 Mode 1: MOSFET OFF BP S Detection of inductor de-magnetization (ZCD) to ensure CrM 7 2 M S Output OVP sensing (120 % of V nominal) OUT 3 6 Steady-state operation voltage range is 1 V 2.4 V S FB Mode 2: MOSFET ON 4 5 D S Line OVP FEEDBACK (FB) Pin: MOSFET current sensing using external current sense resistor Normal operating range is V to 0 V FB(REF) PI-7908-032216 DRAIN (D) Pin: Figure 4. Pin Configuration. High-voltage internal MOSFET. SOURCE (S) Pin: Power and signal ground. 2 Rev. C 07/16 www.power.com