RT8475GS Richtek

RT8475 High Voltage High Current LED Driver Controller for Buck, Boost or Buck-Boost Topology General Description Features zz z zz High Voltage Capability : V Up to 36V, LED Sensing IN The RT8475 is a current mode PWM controller designed Threshold Common Mode Voltage Up to 90V to drive an external MOSFET for high current LED zz z zz Buck, Boost or Buck-Boost Operation applications. With a current sense amplifier threshold of zz z zz Programmable Switching Frequency 190mV, the LED current is programmable with one zz z zz Easy Dimming Control : Analog or Digital external current sense resistor. With the maximum Converting to Analog with One External Capacitor operating input voltage of 36V and output voltage up to zz z zz Programmable Soft-Start to Avoid Inrush Current 90V, the RT8475 is ideal for buck, boost or buck-boost zz z zz Programmable Over Voltage Protection operation. zz z zz V Under Voltage Lockout and Thermal Shutdown IN With the switching frequency programmable over 100kHz zz z zz RoHS Compliant and Halogen Free to 1MHz, the external inductor and capacitors can be small while maintaining high efficiency. Applications Dimming can be done by either analog or digital. The built- z General Industrial High Power LED Lighting in clamping comparator and filter allow easy low noise z Desk Lights and Room Lighting analog dimming conversion from digital signal with only z Building and Street Lighting one external capacitor. z Industrial Display Backlight The RT8475 is available in SOP-14 and WQFN-16L 3x3 Pin Configurations packages. (TOP VIEW) RSET 14 GATE Ordering Information 2 13 ISW GBIAS RT8475 3 12 ISP GND Package Type 4 11 ISN VCC S : SOP-14 VC 5 10 OVP 6 9 ACTL EN QW : WQFN-16L 3x3 (W-Type) 7 8 DCTL SS Lead Plating System G : Green (Halogen Free and Pb Free) SOP-14 Z : ECO (Ecological Element with Halogen Free and Pb free) Note : Richtek products are : 16 15 14 13 RSET 1 12 GND RoHS compliant and compatible with the current require- 2 11 ISW VCC ments of IPC/JEDEC J-STD-020. GND ISP 3 10 OVP 17 Suitable for use in SnPb or Pb-free soldering processes. ISN 4 9 EN 5 6 7 8 WQFN-16L 3x3 Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS8475-03 October 2012 www.richtek.com 1 VC NC ACTL NC DCTL GATE SS GBIASRT8475 Marking Information RT8475GS RT8475ZQW RT8475GS : Product Number 5A : Product Code RT8475 YMDNN : Date Code YMDNN : Date Code 5A YM GSYMDNN DNN RT8475ZS RT8475ZS : Product Number RT8475 YMDNN : Date Code ZSYMDNN Typical Application Circuit L1 R SENSE 22H D1 0.47 V V IN OUT C 4.5V to 36V IN C 90V (Max.) OUT 10F 1F RT8475 M1 11 14 GATE VCC R LEDs SW 0.05 9 2 EN 5V ISW 3 Analog 6 ISP ACTL Dimming 4 7 ISN DCTL R1 10 OVP V 5 OUT VC R VC 8 R R2 RSET SS 10k 30k 1 13 RSET GBIAS C SS C GND VC 0.1F 3.3nF C 12 B 1F Figure 1. Analog Dimming in Boost Configuration D1 C OUT V IN2 1F 90V (max) C IN2 R SENSE V IN1 4.5V to 36V 0.47 C IN1 LEDs 10F RT8475 L1 22H 11 3 ISP VCC 9 4 EN 5V ISN M1 Analog 6 14 ACTL GATE Dimming R SW 7 0.05 DCTL 2 ISW 5 R RSET VC 1 RSET R 8 VC SS 10k 10 13 OVP GBIAS C SS C GND VC 0.1F C 3.3nF B 12 1F Figure 2. Analog Dimming in Buck Configuration Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS8475-03 October 2012 2