www.DataSheet4U.com
YB1521
High Power Step-Up DC-DC Converter & WLED Driver
Features
2.5V to 5.5V Input Voltage Range B...
www.DataSheet4U.com
YB1521
High Power Step-Up DC-DC Converter & WLED Driver
Features
2.5V to 5.5V Input
Voltage Range Built In Power
MOSFET Drive Up to 15V @400mA at 5V Vin Less than 1µA Shutdown Current Up to 94% efficiency Over
Voltage Protection@18V UVLO, Thermal Shutdown Internal 1.6A Current Limit 200mv Low Reference
Voltage Built In Soft Start PWM Dimming SOT23-5 Package Green Package (RoHS) Available
Description
The YB1521 is a step-up DC-DC converter which operating as current source to drive up 45 white LEDs (3S15P) in parallel / series configuration from a 5V system rail. Series connecting of LEDs provides identical LED currents resulting in uniform brightness and eliminating the need for ballast resistors. The light intensity of these LEDs is proportional to the current passing through them. The YB1521 is a fixed frequency of 1.3MHz, allowing the use of tiny low profile inductors and
capacitors to minimize footprint and cost in space consideration applications for cellular phone backlighting or other hand held equipment. The wide input
voltage range from 2.5V to 5.5V is idea for portable applications with higher conversion efficiency. To control LED brightness, the LED current can be pulsed by applying a PWM signal with a frequency which is typically 50 KHz to the EN pin.
Applications
Cellular and Smart Phones Handheld Computers and PDAs Small LCD Displays GPS Terminals MP3 Players Digital Still and Video Cameras Electronic Books
Typical Application Circuit
100...