LM2793

LM2793 Low Noise White LED Constant Current Supply with Dual Function Brightness Control February 2003 LM2793 Low Noise White LED Constant Current Supply with Dual Function Brightness Control General Description The LM2793 is a highly efficient, semi-regulated 1.5x CMOS charge pump that provides dual constant current outputs. The LM2793 has an input voltage range of 2.7V to 5.5V. To control LED brightness, the amount of current driven to the current-mode outputs can be adjusted with an analog voltage and/or a pulse-width-modulated (PWM) square wave. Pre-regulation of the charge pump minimizes conducted noise on the input. Combined with a fixed switching frequency of 500kHz, the LM2793 is a low-noise solution. The LM2793 is available in a 10-pin Leadless Lead-frame package: LLP-10. Features n Two Regulated Current Outputs, up to 16mA Each, Matched to Within ± 0.3% (typ.) n High Efficiency, 1.5x Regulated Charge Pump n Input Voltage Range: 2.7V to 5.5V n Soft Start Limits Inrush Current n Analog Voltage Brightness Control n PWM Brightness Control n Very Small Solution Size - NO INDUCTOR n 500kHz Switching Frequency n 3µA (typ.) Shutdown Current n LLP-10 Package: 3.0mm X 3.0mm X 0.8mm Applications n White LED Display Backlights n White LED Keypad Backlights n 1-Cell LiIon Battery-Operated Equipment Including PDAs, Hand-held PCs, Cellular Phones n Flat Panel Displays Typical Application Circuit 20063602 © 2003 National Semiconductor Corporation DS200636 www.national.com ...