LP5521 Datasheet, PDF (1/14 Pages) National Semiconductor (TI) – Programmable Three Channel LED Driver

June 2007
LP5521
Programmable Three Channel LED Driver
General Description
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.
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.
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.
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.
LP5521 requires only four small and low cost ceramic capac-
itors.
LP5521 is available in tiny 2.1x1.7x0.6 mm microSMD-20
package and in 4.0x5.0x0.8 mm bumped LLP-24 package.
Comprehensive application tools are available, including
command compiler for easy LED sequence programming.
Features
■ ^{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
■ ^{Low input ripple and EMI}
■ ^{Very small solution size, no inductor or resistors required}
■ ^{200 nA typical shutdown current}
■ ^{Automatic power save mode}
■ ^{I2C compatible interface}
■ ^{Independently programmable constant current outputs}
with 8-bit current setting and 8-bit PWM control
■ ^{Typical LED output saturation voltage 50 mV and current}
matching 1%
■ ^{Three program execution engines with flexible instruction}
set
■ ^{Autonomous operation without external control}
■ ^{Large SRAM program memory}
■ ^{Two general purpose digital outputs}
■ ^{microSMD-20 package, 0.4 mm pitch}
■ ^{Bumped LLP-24 package, 0.5 mm pitch}
Applications
■ ^{Fun / indicator lights}
■ ^{LCD sub-display backlighting}
■ ^{Keypad RGB backlighting and phone cosmetics}
■ ^{Vibra, speakers, waveform generator}
Typical Application
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