High Efficiency LED Driver - Microsemi Corporation
Description
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LX1993
I N T E G R A T E D P R O D U C T S
High Efficiency LED Driver
P RODUCTION
DESCRIPTION
KEY FEATURES
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The LX1993 is a high efficiency step-up boost converter that features a psuedo-hysteretic pulse frequency modulation topology for driving white or color LEDs in backlight or frontlight systems.
Designed for maximum efficiency, reduced board size, and minimal cost, the LX1993 is ideal for PDA and digital camera applications.
The LX1993 features an internal N-Channel MOSFET and control circuitry that is optimized for portable system design applications.
The LX1993 promotes improved performance in battery-operated systems by operating with a quiescent supply current 70µA (typical) and a shutdown current of less than 1µA.
The input voltage range is from 1.
6V to 6.
0V thus allowing for a broad selection of battery voltage applications and start-up is
guaranteed at 1.
6V input.
The LX1993 is capable of switching currents in excess of 300mA and the output current is readily programmed using one external current sense resistor in series with the LEDs.
This configuration provides a feedback signal to the FB pin thus maintaining constant output current regardless of varying LED forward voltage (VF).
The LX1993 provides an additional feature for simple dynamic adjustment of the output current (i.
e.
, up to 100% of the maximum programmed current).
Designers can make this adjustment by generating an analog reference signal or a PWM signal applied directly to the ADJ pin and any PWM amplitude is readily accommodated via a single external resistor.
The LX1993 is available in the 8-Pin MSOP and thus requires a very small PCB area.
> 80% Maximum Efficiency 70µA Typical Quiescent Supply Current Externally Programmable Peak Inductor Current Limit For Maximum Efficiency Logic Controlled Shutdown < 1µA Shutdown Current Dynamic Output Current Adjustment Via Analog Reference Or Direct PWM Input 8-Pin MSOP Package APPLICATI...
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