BL8548 Datasheet, PDF (1/6 Pages) SHANGHAI BELLING CO., LTD. – Max. 3MHz, Variable Frequency Step-up DC-DC Converter

BL8548
Max. 3MHz, Variable Frequency Step-up DC/DC Converter
DESCRIPTION
The BL8548 variable frequency step-up Converter
drives white LEDs with a constant current to
provide backlight in cell phones, PDAs, and other
hand-held devices. It features allowing series
connection of the white LEDs so that the LED
currents are identical for uniform brightness. An
enable input can be pulsed repeatedly to adjust
LEDs brightness. The fast 3MHz operation
frequency allows for smaller capacitor and
inductor. Fault condition protection uses cycle-by
cycle current limiting to sense maximum inductor
current and over-voltage protection. The 0.2V
low reference voltage minimized the power loss
across the current sense resistor.
The converter can operate from 2V to 6V, and
capable of delivering maximum 250mA output
current at 4-LEDs application with 3V input
voltage. Quiescent current drawn from power
source is as low as 120uA. All of these features
make BL8548 be suitable for the portable devices,
which are supplied by a single battery.
FEATURES
 Up to 19V Output Voltage
 Wide Operation Range: 2V to 6V
 Maximum 3MHz Operating Frequency
 PWM Dimming Control
 Shutdown Current <1uA
 Current Limit Cycle-by-Cycle
 Low Current Sense Threshold: 200mV
 19V Over Output Voltage Protection
 Compact SOT23-6 Package
APPLICATIONS
 Compact Back Light Module
 Power Source for LED
 Constant Current Source
BL8548 is available in SOT23-6 package that is PB
free.
TYPICAL APPLICATION
BL8548
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Figure1. BL8548 Typical Application Circuit
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