Prema PR4404 LED step-up driving schemeon February 7th, 2012 at 1:39 AM
Prema PR4404 is suitable for 0.5W / 1W power LED low voltage boost driver, from single cell ( 1.2V / 1.5V ) with high 150mA LED tube current to or from the two batteries ( 2.4V / 3.0V ) with high 300mA LED current. Therefore, PR4404 can be widely used in LED torch, LCD screen backlight, family lighting and toys. This paper introduces the main characteristics of PR4404, block diagram, the typical application circuit, a test circuit, a flashlight application circuit, a string of LED drive circuit and PWM control of the LED driving circuit.
Low Voltage Boost Driver PR4404 for 0.5W / 1W Power LEDs
The PR4404 is a step-up converter for white LEDs, operating with single battery cell
Supply ( 1.2 / 1.5V ) at up to 150mA LED current or dual cell supply ( 2.4 / 3.0V ) at up to
300mA LED current.
A minimum part count allows compact and cost-efficient solutions.
The converter can be switched on and off with a logic signal, which is useful for PWM e.g.
Control, timer circuits etc.
The main characteristics of PR4404:
Minimum startup voltage 1.0V
Supply by one or two battery cells
Low number of external components
Battery deep discharge protection
LCD panel backlighting