RT9276GQW Richtek

RT9276 Synchronous Boost Converter with Voltage Detector General Description Features zz z zz True Load Disconnection During Shutdown The RT9276 is a synchronous boost converter, which is zz z zz Internal Synchronous Rectifier based on a fixed frequency Pulse-Width-Modulation zz z zz Up to 96% Efficiency (PWM) controller using a synchronous rectifier to obtain zz z zz Current Mode PWM Operation with Internal maximum efficiency. The converter provides a power Compensation supply solution for products powered by a variety of zz z zz Low Start-Up Voltage batteries such as single cell, dual cell alkaline, NiMH and zz z zz Low Quiescent Current NiCd battery. At light load currents, the converter enters zz z zz Internal Soft-Start Control power save mode to maintain a high efficiency over a wide zz z zz Low Battery Comparator load current range. zz z zz Low EMI Converter (Anti-Ringing) The output voltage can be programmed by an external zz z zz Power Save Mode for Improved Efficiency at Light resistor divider, or fixed at a certain voltage. Moreover, the Load Current converter can be disabled to minimize battery drain. During zz z zz Over Current Protection shutdown, the load is completely disconnected from the zz z zz Short Circuit Protection battery. The maximum peak current in the boost switch zz z zz Over Temperature Protection is limited to 2A for current limit. zz z zz Over Voltage Protection For the RT9276, a low-EMI mode is implemented to reduce zz z zz Small WDFN-10L 3x3 Package ringing of the inductor phase pin when the converter enters zz z zz RoHS Compliant and Halogen Free discontinuous conduction mode. Moreover, a voltage detector is built-in in the chip for low battery detection. Applications z All One-Cell, Two-Cell and Three-Cell Alkaline, NiCd, Ordering Information NiMH and Single-Cell Li Batteries RT9276(- ) z Hand-Held Devices Package Type z WLED Flash Light QW : WDFN-10L 3x3 (W-Type) Lead Plating System Pin Configurations G : Green (Halogen Free and Pb Free) (TOP VIEW) Boost VOUT Default : Adjustable EN 1 10 PGND 33 : 3.3V 2 9 VOUT LX 3 FB/NC 8 PGOOD 50 : 5.0V 4 7 LBO LBI GND 5 11 6 VBAT Note : WDFN-10L 3x3 Richtek products are : RoHS compliant and compatible with the current require- Marking Information ments of IPC/JEDEC J-STD-020. EW= : Product Code Suitable for use in SnPb or Pb-free soldering processes. YMDNN : Date Code EW=YM DNN Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS9276-02 July 2013 www.richtek.com 1 GNDRT9276 Typical Application Circuit RT9276 L 2 9 V LX VOUT V OUT BAT 6 VBAT C IN R3 C OUT R1 3 R5 R6 FB 7 R4 LBI 4 LBO LBO R2 10 PGND 8 PGOOD PGOOD 5, Exposed Pad (11) Chip Enable 1 EN GND Figure 1. Adjustable Output Voltage Boost Converter with Voltage Detector RT9276 L 9 2 V LX VOUT V OUT BAT 6 VBAT C IN R3 C OUT R1 4 LBO R4 7 LBI 8 R2 PGOOD PGOOD 10 PGND 3 NC Chip Enable 5, Exposed Pad (11) 1 EN GND Figure 2. Fixed Output Voltage Boost Converter with Voltage Detector Functional Pin Description Pin No. Pin Name Pin Function 1 EN Chip Enable (Active High). 2 VOUT Boost Output. Feedback Input for Adjustable Output Voltage Version / No Internal Connection 3 FB / NC for Fixed Output Voltage Version. 4 LBO Voltage Detector Output. 5 GND Ground. 6 VBAT Battery Supply Input. 7 LBI Voltage Detector Input. 8 PGOOD Power Good Indicator. 9 LX Switching Node. Connect this pin to an inductor. 10 PGND Power Ground. Ground. The exposed pad must be soldered to a large PCB and connected to 11 (Exposed Pad) GND GND for maximum power dissipation. Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS9276-02 July 2013 2