LM2751 Datasheet, PDF (1/11 Pages) National Semiconductor (TI) – Regulated 2X, 1.5X Switched Capacitor White LED Driver

April 2005
LM2751
Regulated 2X, 1.5X Switched Capacitor White LED Driver
General Description
The LM2751 is a constant frequency switched capacitor
charge pump with regulated output voltage options of 4.5V,
and 5.0V. Over the input voltage range of 2.8V to 5.5V the
LM2751 provides up to 150mA of output current and requires
only four low-cost ceramic capacitors.
The LM2751 provides excellent efficiency without the use of
an inductor by operating the charge pump in a gain of 3/2 or
2. The proper gain for maintaining regulation is chosen so
that efficiency is maximized over the input voltage range.
LM2751 uses constant frequency pre-regulation to minimize
conducted noise on the input and provide a predictable
switching frequency. The switching frequency is program-
mable to 725kHz, 300kHz, 37kHz, or 9.5kHz.
LM2751 is available in a 10-pin Leadless Leadframe No-
Pullback Package: LLP-10.
Features
n Regulated Output Options: 4.5V, 5.0V
n Output Voltage Regulated within 3%
n Peak Efficiency Over 90%
n 150mA (4.5V) or 80mA (5.0V) Output Current Capability
n Input Voltage Range: 2.8V to 5.5V
n Low Input and Output Voltage Ripple
n <1µA Typical Shutdown Current
n Small Solution Size - NO INDUCTOR
n Programmable 725kHz, 300kHz, 37kHz, or 9.5kHz
Switching Frequencies
n 10-pin LLP No-Pullback Package: 3mm x 3mm x 0.8mm
Applications
n White LED Display Backlights
n White LED Keypad Backlights
n General Purpose 2x, 1.5x Regulated Charge Pump
Typical Application Circuit
LM2751 2x/1.5x Efficiency vs.
2x Charge Pump Effciency
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© 2005 National Semiconductor Corporation DS201121
20112128
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