WHITE LED STEP-UP CONVERTER
DESCRIPTION
The UTC L5101 is a constant current step-up PWM DC/DC
converter optimized to drive white LEDs. It can drive LEDs in series
with a Li-Ion cell.
The switching frequency of the internal NPN is up to 1.2MHz.
High frequency allows the use of tiny external components and the
current setting resistor has minimum power dissipation for the low
feedback voltage of 95mV. The built-in OVP prevents the UTC
L5101 damage from the open load condition.
Series connection of LEDs provides identical LED currents which
contributes to uniform brightness, saving the use of ballast
resistors.
The UTC L5101 is universally used in cellular phones, PDAs ,
DSCs, handheld devices, and white LED display backlighting.
FEATURES
* Open Circuit and Over Voltage Protection
* High Efficiency: 86% Typical
* Switching Frequency: 1.2MHz
* Supply Current is 1.0mA
* Matches LED Current
* Requires Tiny Inductor and Capacitors
* Halogen Free
TYPICAL APPLICATION CIRCUITS
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