RT9276GQW

® RT9276 Synchronous Boost Converter with Voltage Detector General Description Features The RT9276 is a synchronous boost converter, which is based on a fixed frequency Pulse-Width-Modulation (PWM) controller using a synchronous rectifier to obtain maximum efficiency. The converter provides a power supply solution for products powered by a variety of batteries such as single cell, dual cell alkaline, NiMH and NiCd battery. At light load currents, the converter enters power save mode to maintain a high efficiency over a wide load current range. z True Load Disconnection During Shutdown z Internal Synchronous Rectifier Up to 96% Efficiency Current Mode PWM Operation with Internal Compensation Low Start-Up Voltage Low Quiescent Current Internal Soft-Start Control Low Battery Comparator Low EMI Converter (Anti-Ringing) Power Save Mode for Improved Efficiency at Light Load Current Over Current Protection Short Circuit Protection Over Temperature Protection Over Voltage Protection Small WDFN-10L 3x3 Package RoHS Compliant and Halogen Free The output voltage can be programmed by an external resistor divider, or fixed at a certain voltage. Moreover, the converter can be disabled to minimize battery drain. During shutdown, the load is completely disconnected from the battery. The maximum peak current in the boost switch is limited to 2A for current limit. z z z z z z z z z z z z For the RT9276, a low-EMI mode is implemented to reduce ringing of the inductor phase pin when the converter enters discontinuous conduction mode. Moreover, a voltage detector is built-in in the chip for low battery detection. Ordering Information ) z Applications z z All One-Cell, Two-Cell and Three-Cell Alkaline, NiCd, NiMH and Single-Cell Li Batteries Hand-Held Devices WLED Flash Light Package Type QW : WDFN-10L 3x3 (W-Type) z Lead Plating System G : Green (Halogen Free and Pb Free) Pin Configurations (TOP VIEW) Boost VOUT Default : Adjustable 33 : 3.3V 50 : 5.0V EN VOUT FB/NC LBO GND 1 2 3 4 5 GND RT9276(- z 11 10 9 8 7 6 PGND LX PGOOD LBI VBAT Note : WDFN-10L 3x3 Richtek products are : ` RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. ` Marking Information EW= : Product Code Suitable for use in SnPb or Pb-free soldering processes. EW=YM DNN Copyright © 2013 Richtek Technology Corporation. All rights reserved. DS9276-02 July 2013 YMDNN : Date Code is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT9276 Typical Application Circuit L VBAT CIN RT9276 2 9 LX VOUT 6 VBAT VOUT R3 COUT FB 3 R1 7 R2 10 PGND Chip Enable R5 R6 R4 LBI LBO 4 8 PGOOD 1 EN GND LBO PGOOD 5, Exposed Pad (11) Figure 1. Adjustable Output Voltage Boost Converter with Voltage Detector L VBAT CIN RT9276 2 9 LX VOUT 6 VBAT 7 Chip Enable R3 COUT LBO 4 R1 R2 VOUT R4 LBI 10 PGND PGOOD 1 EN 8 PGOOD NC 3 GND 5, Exposed Pad (11) 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. 3 FB / NC Feedback Input for Adjustable Output Voltage Version / No Internal Connection 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. 11 (Exposed Pad) GND Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Copyright © 2013 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 is a registered trademark of Richtek Technology Corporation. DS9276-02 July 2013 RT9276 Function Block Diagram PGOOD VOUT Determine Higher Voltage Soft-Start Control EN OCP, OTP, OVP VREF1 EA FB VBAT Logic UGATE Control Back Gate Control LX PWM LGATE Current Sense GND Internal Compensation PGND LBO VREF2 + - LBI Figure 3. Adjustable Voltage Regulator PGOOD VOUT Determine Higher Voltage Soft-Start Control EN VREF1 OCP, OTP, OVP VOUT VBAT Logic UGATE Control Back Gate Control LX EA LGATE PWM Current Sense PGND GND LBO Internal Compensation VREF2 + - LBI Figure 4. Fixed Voltage Regulator Copyright © 2013 Richtek Technology Corporation. All rights reserved. DS9276-02 July 2013 is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT9276 Absolute Maximum Ratings z z z z z z z z z z z z (Note 1) Supply Input Voltage, VBAT ---------------------------------------------------------------------------------------------Boost Output Voltage, VOUT -------------------------------------------------------------------------------------------Switch Output Voltage, LX ---------------------------------------------------------------------------------------------