RT4531 Dual Channel 10s2p WLED Drivers General Description Features Input Voltage Range : 2.5V to 5.5V The RT4531 is a dual-channel current source with high- Internal Soft-Start, UVLO, OTP, OCP, OVP efficiency asynchronous boost converter for backlight Typical Shutdown Current : < 1A application. The RT4531 has built-in 1.5A/36V power 1MHz Switching Frequency MOSFET and two high current-matching capability current Drives Up to 10 WLEDs in Two Strings sink, so RT4531 can drives up 10s2p white LED. The Independent PWM Dimming and 1-Wire Dimming RT4531 can allow very low voltage headroom control, Control therefore to improve LED strings efficiency effectively. PWM Dimming Frequency from 20k to 100kHz The RT4531 supports both PWM dimming and 1-wire Up to 10 Bit Dimming Resolution digital dimming interface and it can realize 10 bit LED Current Accuracy 2% ( > 5mA) brightness code programming. LED Current Matching 2% ( > 5mA) The RT4531 provides complete protection functions such Built-in IFB1/IFB2 pin OVP, Short Protection, and as input Under-Voltage Lockout (UVLO), Over-Current Un-Use Detection Protection (OCP), Output Over Voltage (OVP) and Over- Temperature Protection (OTP). Ordering Information The RT4531 is available in the WL-CSP-9B 1.35x1.35 RT4531 (BSC) package. Package Type WSC : WL-CSP-9B 1.35x1.35 (BSC) Applications Note : Smart Phones Richtek products are : Probable Instruments RoHS compliant and compatible with the current require- Backlight for Small and Media Form ments of IPC/JEDEC J-STD-020. Factor LCD Display with Single-cell Battery Input Suitable for use in SnPb or Pb-free soldering processes. Simplified Application Circuit L V IN C1 R1 C3 VIN SW C2 RT4531 2P10S WLEDs Enable EN IFB1 PWM Dimming PWM IFB2 ISET GND AGND R2 Copyright 2016 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS4531-01 July 2016 www.richtek.com 1RT4531 Pin Configurations Marking Information (TOP VIEW) 33 : Product Code 33W W : Date Code A1 A2 A3 ISET IFB1 B1 B2 B3 PWM GND AGND C1 C2 C3 EN SW WL-CSP-9B 1.35x1.35 (BSC) Functional Pin Description Pin No. Pin Name Pin Function Full-Scale LED Current Set Pin. Connecting a resistor to the pin programs the A1 ISET full-scale LED current. A2 IFB2 Single Output 2 for Backlight LED. A3 IFB1 Single Output 1 for Backlight LED. B1 PWM Enable Control, and PWM Dimming Signal Input. B2 AGND Analog Ground. B3 GND Power Ground. C1 EN Enable Control, and 1-Wire Dimming Signal Input. C2 VIN Supply Input Pin. C3 SW Switch Node of Boost Converter. Copyright 2016 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS4531-01 July 2016 www.richtek.com 2 IFB2 VIN