RT8555 2 36V High Efficiency Boost Converter with I C Controlled 6-CH LED Driver General Description Features Wide Operating Input Voltage : 2.7V to 24V The RT8555 is a high efficiency driver for white LEDs. It is High Output Voltage : Up to 36V suitable for single/two cell battery input to drive LED light Programmable Channel Current : 10mA to 35mA bars which contains six strings in parallel and up to Channel Current Regulation with Accuracy 3% 10 WLEDs per string. The internal current sinks support and Matching 2% a maximum of 2% current mismatching for excellent Dimming Controls brightness uniformity in each string of LEDs. To provide Direct PWM Dimming up to 20kHz and Minimum enough headroom for current sink operation, the Boost On-Time to 400ns controller monitors the minimum voltage of the feedback PWM to Analog Dimming up to 20kHz with 8-bit pins and regulates an optimized output voltage for power Resolution efficiency. 2 I C Programs LED Current, Switching Frequency, The RT8555 has a wide input voltage operating range from Dimming Mode 2 2.7V to 24V and contains I C interface for controlling the Switching Frequency : 300kHz to 2MHz dimming mode, operating frequency and the LED current. Protections The internal 100m, 36V power switch with current-mode LED Strings Open Detection control provides over-current protection. The switching Current Limit frequency of the RT8555 is adjustable from 300kHz to Programmable Over Voltage Protection 2MHz, which allows flexibility between efficiency and Over-Temperature Protection component size. 20-Ball WL-CSP, with pitch 0.4mm Package The RT8555 is available in the WL-CSP-20B 1.65 x 2.05 RoHS Compliant and Halogen Free (BSC), with pitch 0.4mm package. Applications Ordering Information Tablet and Notebook Backlight RT8555 Package Type WSC : WL-CSP-20B 1.65x2.05 (BSC) Pin Configurations Note : (TOP VIEW) Richtek products are : A1 A2 A3 A4 RoHS compliant and compatible with the current require- LX PGND SDA SCL ments of IPC/JEDEC J-STD-020. B1 B2 B3 B4 Suitable for use in SnPb or Pb-free soldering processes. LX PGND PWM EN C1 C2 C3 C4 VIN VOUT GND FB3 D1 D2 D3 D4 Marking Information VIN VCP GND FB2 1X : Product Code E1 E2 E3 E4 W : Date Code 1XW FB6 FB5 FB4 FB1 WL-CSP-20B 1.65 x 2.05 (BSC) Copyright 2015 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS8555-00 June 2015 www.richtek.com 1RT8555 Functional Pin Description Pin No. Pin Name. Pin Function A1, B1 LX Switch Node of Boost Converter. A2, B2 PGND Power Ground. 2 A3 SDA Data Signal Input of I C Interface. 2 A4 SCL Clock Signal Input of I C Interface. B3 PWM PWM Dimming Control Input. B4 EN Enable Control Input (Active High). C1, D1 VIN Power Input. C2 VOUT Output of Boost Converter. C3, D3 GND Ground. C4 FB3 Current Sink for LED3. D2 VCP Output of Internal Regulator. D4 FB2 Current Sink for LED2. E1 FB6 Current Sink for LED6. E2 FB5 Current Sink for LED5. E3 FB4 Current Sink for LED4. E4 FB1 Current Sink for LED1. Copyright 2015 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS8555-00 June 2015 2