Diodes AL3159 User Manual
Al3159, New prod uc t description, Features
AL3159
HIGH EFFICIENCY 1x/2x CHARGE PUMP
FOR WHITE LED APPLICATIONS
AL3159
Document number: DS35048 Rev. 2 - 2
1 of 10
January 2011
© Diodes Incorporated
NEW PROD
UC
T
Description
The AL3159 is a low noise, constant frequency charge pump
DC/DC converter that uses a Dual mode load switch (1x), and (2x)
conversion for white LED applications. The AL3159 is capable of
driving nine LED channels at 20mA from a 2.7V to 5.5V input. The
current sinks may be operated using three simple logic control
inputs individually or in parallel for driving higher-current LEDs. Low
external part counts (one 1µF flying capacitor and two
2.2µF capacitors at V
IN
and V
OUT
) make this part ideally suited for
small, battery-powered applications.
AL3159 digital inputs are used to enable or disable the
LED channels with a fixed default current settings at 20mA or other
factory programming options available.
Each output of the AL3159 is equipped with built-in protection for
V
OUT
short circuit and auto-disable for LED short conditions. Built-in
soft-start circuitry prevents excessive inrush current during start-up
and mode switching. A low-current shutdown feature disconnects
the load from V
IN
to reduce quiescent current less than 1µA.
The AL3159 is available in a lead-free, space-saving, thermally
enhanced 20-pin 3 x 3mm QFN package.
Features
• V
IN
range: 2.7V to 5.5V
• Up to 93% Max Power Efficiency
• 1% Current Matching Accuracy Between Channels
• Drives up to 9 configurable Channels of LEDs
• Three simple logic decoding LED On/Off control inputs
• Low transition threshold voltage typical 150 mV
• Dual-Mode 1x and 2x Charge Pump
• 1.2 MHz Constant Switching Frequency
• V
OUT
short circuit and Thermal Protections
• Soft Start for reducing inrush current
• I
Q
<1µA in Shutdown
• Thermally-Enhanced QFN3030-20 Package: Available in
“Green” Molding Compound (No Br, Sb)
• Lead Free Finish/ RoHS Compliant (Note 1)
Pin Assignments
Applications
• Mobile Phone White LED Backlighting and Indicators
• PDA White LED backlighting
• Battery-operated Phone Main and Sub Screen White LED
Backlighting
Notes: 1.
EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
Typical Application Circuit