SY5839ABC

Application Notes: AN_SY5839 Single Stage Buck PFC Controller For LED Lighting Preliminary datasheet General Description Features The SY5839 is a single stage Buck PFC controller targeting at LED lighting applications. It is a primary side controller without applying any secondary feedback circuit for low cost, and drives the Flyback converter in the quasi-resonant mode to achieve higher efficiency. It keeps the Flyback converter in constant on time operation to achieve high power factor. It adopts special design to achieve quick start up and reliable protection for safety requirement. • Applications Ordering Information • • • • • SY5839 □(□□)□ Tempera ture Code Packa ge Code Optional Spec Code Ordering Number SY5839ABC Package type SOT23-6 • • • • • • Valley turn-on of the MOSFET to achieve low switching losses Power factor >0.90 with single-stage conversion. Low start up current: 15µ A typical Quick start up 0.90 with single-stage conversion. Compact package: SOT23-6 LED lighting Down light Tube lamp PAR lamp Bulb l mp Note ---- Typical Applications Efficiency vs. Input Voltage (VAC) Efficiency (%) 93 92 91 IO=225mA PO=18W 90 170 190 210 230 250 270 Input Voltage (V) Figure 1. Schematic Diagram AN_SY5839 Rev. 0.1 Figure 2. Efficiency vs Input Voltage Silergy Corp. Confidential-Prepared for Customer Use Only 1 AN_SY5839 Pinout (top view) (SOT-23) Top Mark: ZTxyz (device code: ZT, x=year code, y=week code, z= lot number code) Pin Name Pin Number ISEN 1 GND 2 COMP 3 VSEN 4 VIN 5 DRV 6 AN_SY5839 Rev. 0.1 Pin Description Current sense pin. Connect this pin to the source of the switch. Connect the sense resistor across the source of the switch and the GND pin. (current sense resister RS: I V = 1 × REF ) .Also this pin used to detect o 2 RS transformer and secondary is short or not. Ground pin Loop compensation pin. Connect a RC network across this pin and ground to stabilize the cont ol loop. Inductor current zero-crossing detection pin. This pin receives the auxiliary winding vo tage by a resister divider and detects the inductor current zero crossing point. This pin also provides over voltage protection and l ne regulation modification function simultaneously. If the voltage on this pin is above VSEN,OVP, the IC would enter over voltage prot ction mode. Good line regulation can be achieved by adjust ng the upper resistor of the divider. Power supply pin. This pin also provides output over voltage protection alo g with VSEN pin. Gate drive pin. Connect this pin to the gate of MOSFET. Silergy Corp. Confidential-Prepared for Customer Use Only 2 AN_SY5839 Absolute Maximum Ratings (Note 1) VIN, DRV ------------------------------------------------------------------------------------------------------------------Supply Current IVIN -------------------------------------------------------------------------------------------------------------VSEN------------------------------------------------------------------------------------------------------------------ISEN, COMP ---------------------------------------------------------------------------------------------------------------Power Dissipation, @ TA = 25°C SOT23-6 ------------------------------------ -----------------------------------------------Package Thermal Resistance (Note 2) SOT23-6, θJA ------------------------------------------------------------------------------------------------------SOT23-6, θJC ------------------------------------------------------------------------------------------------------Junction Temperature Range ---------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------------------Storage Temperature Range ----------------------------------------------------------------------------------------- 0.3V~33V 15mA -0.3V ~VIN+0.3 0.3~3.6V 0.6W - - 170°C/W 130°C/W -40°C to 150°C 260°C -65°C to 150°C Recommended Operating Conditions (Note 3) VIN, DRV -------------------------------------------------------------------------------------------------------------------Junction Temperature Range ---------------------------------------------------------------------------------------- 9.5V~27V -40°C to 125°C Block Diagram Figure3. Block Diagram AN_SY5839 Rev. 0.1 Silergy Corp. Confidential-Prepared for Customer Use Only 3 AN_SY5839 Electrical Characteristics (VIN = 12V (Note 3), TA = 25°C unless otherwise specified) Parameter Power Supply Section VIN turn-on threshold VIN turn-off threshold VIN OVP voltage Start up Current Shunt current in OVP mode Error Amplifier Section Internal reference voltage Current Sense Section Current limit voltage Protection limit for TR short CC Feedforward coefficient CC Feedforward resistor COMP section Pre-charge value VSEN pin Section VSEN pin OVP voltage threshold Fast start up theshold Gate Driver Section Gate driver voltage Maximum source current Minimum sink current Max ON Time Max OFF Time Blanking time for ON time Blanking time for OFF time Maximum switching frequency Thermal Section Thermal Shutdown Temperature Symbol Test Conditions V VIN,ON V Typ Max Unit 25.3 8.5 30.0 15 4.7 V V V µA mA 0.3 V V V 2 0.75 1.5 0.1 K2 340 Ω COMP,LIM 1.4 V VIN,OFF V VIN,OVP I ST I VIN,OVP V V Min V V VIN VIN VIN,OFF VIN,OVP REF ISEN,LIMIT V ISEN,EX K R V V VSEN,OVP V VSEN,ST V I Gate SOURCE I T T SINK ON,MAX OFF,MAX T T ON,BLK OFF,BLK f MAX T SD ISEN=0V VFB