SY8745FCC

Application Note: AN_SY8745 High Efficiency, 10-60V Input, 500kHz White LED Driver Preliminary datasheet General Description Features SY8745 is a high efficiency, 10V-60V wide input voltage range DC/DC regulator targeting at LED applications. The device integrates the low RDS(ON) MOSFET and internal compensation. Along with the small SO8E package, the device achieves an extremely small solution size for LED driver design. SY8745 also supports PWM/Analog dimming function. • • Ordering Information Applications SY8745 □(□□)□ • • • • Wide input range: 10-60 V 500kHz switching frequency Integrated low RDS(ON) FET: 0.16Ω PWM/Analog dimming available 1.5A LED current output Compact package: SO8E • LED lighting Tempera ture Code Packa ge Code Optional Spec Code Ordering Number SY8745FCC Package type SO8E Note ---- Typical Applications Figure 1. Schematic diagram AN_SY8745 Rev.0.1 Silergy Corp. Confidential- Prepared for Customer Use Only 1 AN_SY8745 Pinout (top view) SO8E Top Mark: AZTxyz (device code: AZT, x=year code, y=week code, z= lot number code) Pin Name SO8E IN 5 SEN 6 4 And Exposed Pad GND LX 3 EN 7 CF 2 NC 1,8 Pin Description Input pin. Decouple this pin to GND pin with 1uF ceramic cap. Also used as the positive current sense pin. Negative Current Sense Pin. Ground pin Inductor node. Connect an induct r from power input to LX pin. Enable pin and PWM dimming input pin. If VEN>8V, IC work at 0~1V linear dimming, dimming signal add to CF. If VEN1.5V, IC work at PWM dimming mode, when VCF IOUT , Applications Information Because of the high integration in the SY8745 IC, the application circuit based on this regulator IC is rather simple. Only input capacitor CIN, output capacitor COUT, output inductor L and current sense resistor RSEN need to be selected for the targeted applications specifications. Current sense resistor RSEN: Choose RSEN to program the proper output Current: 0.1(V) = ILED(A) RSEN (Ω) Input capacitor CIN: The ripple current through input capacitor is calculated as: MAX + V OUT (1-VOUT /VIN, ) MAX 2 ⋅ FSW ⋅ L Dimming Operation: Analog dimming: 1:0~1.0V linear dimming. Set VEN>8V, and add 0~1V dimming signal to CF PIN. 2: Applied with PWM signal. Connect a capacitor to CF PIN to filler reference inte , and add PWM signal to EN PIN (VEN_HIGH1.5V, and add PWM signal to EN PIN. PWM CF Dimming mode ->1.5 PWM dimming PWM>8