1 Features
1• Adaptive Charge Pump With 1× and 1.5× 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

2 Applications
• Fun and Indicator Lights
• LCD Sub-Display Backlighting
• Keypad RGB Backlighting and Phone Cosmetics
• Vibra, Speakers, Waveform Generator
• Blood Glucose Meter
• Handheld POS Terminals
• Electronic Access Control
• Where RGB Indication is Needed

3 Description
The LP5521 is a three-channel LED driver designed
to produce variety of lighting effects for mobile
devices. A high-efficiency 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 memory has been
loaded, LP5521 can operate autonomously without
processor control allowing power savings.
The device maintains excellent efficiency over a wide
operating range by automatically selecting proper
charge pump gain based on LED forward voltage
requirements and 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
programmable current sources and PWM control.
Each channel has program memory for creating
desired lighting sequences with PWM control.
The LP5521 has a flexible digital interface. Trigger
I/O and a 32-kHz clock input allow synchronization
between multiple devices. Interrupt output can be
used to notify processor, when LED sequence has
ended. The LP5521 has four pin selectable I2Ccompatible
addresses. This allows connecting up to
four parallel devices in one I2C-compatible bus. GPO
and INT pins can be used as a digital control pin for
other devices.
The LP5521 requires only four small, low-cost
ceramic capacitors.
Comprehensive application tools are available,
including command compiler for easy LED sequence
programming.