LYT2002-2005 LYTSwitch-2 Family Energy-Efficient, Accurate Primary-Side Regulation CC/CV Switcher for LED Lighting Applications Product Highlights Accurate CC Regulation, Meets 3% in a Typical 1 Design Controller Automatically Compensates For: Transformer inductance variation External component changes with temperature AC Input line voltage variations IN D FB This enhances production yield LYTSwitch-2 BP Cost-Effective, Small Size Designs S Eliminates the optocoupler and secondary CC control circuitry Eliminates control loop compensation circuitry PI-7037a-051914 Frequency-jitter greatly reduces EMI filter cost Programmable switching frequency reduces transformer size Figure 1. Typical Flyback Implementation Not a Simplified Circuit. 725 V switching power MOSFET enables clampless flyback designs Advanced Protection/Safety Features Auto-restart protection reduces power delivered by >90% for output short-circuit and control loop faults (open and short-circuit components) Hysteretic thermal shutdown with automatic recovery Meets high-voltage creepage requirements between DRAIN and all other pins both on the PCB and at the package 2 Output Power Table EcoSmart Energy Efficient 90-308 VAC 1 No-load consumption <30 mW 5 Product No current sense resistors maximizes efficiency 3 4 Enclosed Bulb Ballast Driver Green Package LYT2002D 5 W 6 W All parts are halogen free and RoHS compliant LYT2003D 6 W 7 W Applications LYT2004D 7 W 8 W LED bulbs, down lights, luminaires, ballasts and T8 tubes LYT2004E/K 9 W 10 W Description LYT2005E/K 10 W 12 W The LYTSwitch-2 family of ICs dramatically simplifies low power CC Table 1. Output Power Table. LED drivers by eliminating the optocoupler and secondary control Notes: circuitry. The family introduces a revolutionary control technique which 1. Nominal input and bias supply applied to BYPASS pin. 2. Performance for typical design. provides accurate output current regulation, compensating for 3. Maximum continuous power in a typical non-ventilated bulb measured at +50 transformer and external component variations, and device parameter C ambient, device T 100 C. J tolerances as well as input voltage variations. 4. Maximum practical continuous power in an open frame design with adequate heat sinking, measured at +50 C. The device incorporates a high-voltage switching MOSFET, an ON/OFF 5. Packages: D: SO-8C, E: eSIP-7C, K: eSOP-12B. control state-machine, a high-voltage switched current source for self-biasing, frequency jitter to reduce EMI, cycle-by-cycle current limit and hysteretic thermal shutdown circuitry into a monolithic IC. This high level of integration enables cost-effective designs with very few external components, reducing solution cost and driver size. LYTSwitch-2 parts minimize energy consumption when the output is unloaded. Practical designs can easily achieve less than 30 mW no-load consumption. The 725 V power MOSFET used in LYTSwitch-2 devices increases the circuits ability to withstand input surge. In addition, each package is designed to maximize the creepage distance between high-voltage pins and logic level inputs. This increased pin spacing increases driver lifetime and reliability in polluted environments. These in-built protec- tion features also protect the entire circuit from excess temperature operation, increasing lifetime in thermally challenging environments. www.power.com September 2015 This Product is Covered by Patents and/or Pending Patent Applications.D S NC NC BP FB LYT2002-2005 DRAIN (D) REGULATOR BYPASS 6 V (BP) + FB 6 V - + OUT 5 V Reset D Q STATE FEEDBACK V TH - MACHINE (FB) V ILIMIT t SAMPLE-OUT I Drive LIM DC MAX FAULT 6.5 V FB AUTO-RESTART OPEN-LOOP t THERMAL SAMPLE-INPUT INDUCTANCE SHUTDOWN CORRECTION DC MAX t SAMPLE-OUT SAMPLE t DELAY SAMPLE-INPUT OSCILLATOR SOURCE (S) I LIM SOURCE V ILIMIT CONSTANT (S) CURRENT Current Limit LEADING Comparator EDGE BLANKING PI-7302-061214 Figure 2. Functional Block Diagram. Pin Functional Description E Package DRAIN (D) Pin: (eSIP-7C) Power MOSFET drain connection. It also provides internal Exposed Pad operating current during start-up and in steady-state operation. (On Back Side) Internally BYPASS (BP) Pin: Connected to Connection point for the external 1 mF bypass capacitor connected to SOURCE Pin D Package (SO-8C) the internally generated 6 V supply. FEEDBACK (FB) Pin: FB 1 8 S Controls switching of the power MOSFET during normal opera- BP 2 7 S 1 2 3 4 5 7 tion. This pin senses the AC voltage on the bias winding. 6 S Input is used to regulate both the output voltage in CV mode and output current in CC mode based on voltage across the D 4 5 S bias winding in the flyback portion of the switching cycle. The internal inductance correction circuit uses voltage on the bias Exposed Pad (On Bottom) winding during forward part of the switching cycle to sense the K Package Internally Connected to bulk capacitor voltage. (eSOP-12B) SOURCE Pin FB 1 12 S SOURCE (S) Pin: Connected to the MOSFET source and is used for high-voltage BP 2 11 S power and control circuit common returns. NC 3 10 S NC 4 9 S 8 S D 6 7 S PI-6906-051614 Figure 3. Pin Configuration. 2 Rev. B 09/15 www.power.com - +