June 2007
LP5521
Programmable Three Channel LED Driver
General Description
Features
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The LP5521 is a three channel LED driver designed to pro-
duce variety of lighting effects for mobile devices. High effi-
ciency charge pump enables LED driving over full Li-Ion
battery voltage range. The device has a program memory for
creating variety of lighting sequences. When program mem-
ory has been loaded, LP5521 can operate independently
without processor control.
Adaptive charge pump with 1x and 1.5x gain provides up
to 95% LED drive efficiency
Charge pump with soft start and overcurrent/short circuit
protection
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Low input ripple and EMI
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Very small solution size, no inductor or resistors required
200 nA typical shutdown current
Automatic power save mode
LP5521 maintains excellent efficiency over a wide operating
range by automatically selecting proper charge pump gain
based on LED forward voltage requirements. LP5521 is able
to automatically enter power-save mode, when LED outputs
are not active and thus lowering current consumption.
I2C compatible interface
Independently programmable constant current outputs
with 8-bit current setting and 8-bit PWM control
Three independent LED channels have accurate pro-
grammable current sources and PWM control. Each channel
has program memory for creating desired lighting sequences
with PWM control.
Typical LED output saturation voltage 50 mV and current
matching 1%
Three program execution engines with flexible instruction
set
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LP5521 has a flexible digital interface. Trigger I/O and 32 kHz
clock input allow synchronization between multiple devices.
Interrupt output can be used to notify processor, when LED
sequence has ended. LP5521 has four pin selectable I2C ad-
dresses. This allows connecting up to four parallel devices in
one I2C bus. GPO and INT pins can be used as a digital con-
trol pin for other devices.
Autonomous operation without external control
Large SRAM program memory
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Two general purpose digital outputs
microSMD-20 package, 0.4 mm pitch
Bumped LLP-24 package, 0.5 mm pitch
LP5521 requires only four small and low cost ceramic capac-
itors.
Applications
Fun / indicator lights
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LP5521 is available in tiny 2.1x1.7x0.6 mm microSMD-20
package and in 4.0x5.0x0.8 mm bumped LLP-24 package.
LCD sub-display backlighting
Keypad RGB backlighting and phone cosmetics
Comprehensive application tools are available, including
command compiler for easy LED sequence programming.
Vibra, speakers, waveform generator
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Typical Application
20186270
© 2007 National Semiconductor Corporation
201862
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