LM2793 Datasheet, PDF (1/10 Pages) National Semiconductor (TI) – 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 fre-
quency 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
© 2003 National Semiconductor Corporation DS200636
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