AL3158
HIGH EFFICIENCY 1x/2x CHARGE PUMP
FOR WHITE LED APPLICATIONS
Description Pin Assignments
The AL3158 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 AL3158 is capable of
driving three groups of three LED channels at 20mA from a 2.7V to
5.5V input. The current sinks may be operated using three simple
PWM dimming inputs individually or in parallel for driving higher-
current LEDs. Low external part counts (one 1F flying capacitor
and two 2.2F capacitors at V and V ) make this part ideally
IN OUT
suited for small, battery-powered applications.
AL3158 PWM dimming inputs are used to enable, disable device
and dimming LED current with a fixed default current settings at
20mA or other factory programming options available.
Each output of the AL3158 is equipped with built-in protection for
V short circuit and auto-disable for LED short conditions. Built-in
OUT
soft-start circuitry prevents excessive inrush current during start-up
and mode switching. A low-current shutdown feature disconnects
the load from V to reduce quiescent current less than 1A.
IN
The AL3158 is available in a lead-free, space-saving, thermally
enhanced 20-pin 3 x 3mm QFN package.
Features Applications
V Range: 2.7V to 5.5V Mobile Phone White LED Backlighting and Indicators
IN
PDA White LED Backlighting
Up to 93% Max Power Efficiency
Battery-operated Phone Main and Sub Screen White LED
1% Current Matching Accuracy Between Channels
Backlighting
Three simple PWM dimming for RGB or WLED
Low transition threshold voltage typical 150 mV
Dual-Mode 1x and 2x Charge Pump
Drives up to 3 + 3 + 3 Channels of LEDs
1.2 MHz Constant Switching Frequency
V short circuit and Thermal Protections
OUT
Soft Start for reducing inrush current
Under Voltage Lockout Protection
I <1A in Shutdown
Q
Thermally-Enhanced QFN3030-20 Package: Available in Green
Molding Compound (No Br, Sb)
Lead Free Finish/ RoHS Compliant (Note 1)
Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
AL3158
HIGH EFFICIENCY 1x/2x CHARGE PUMP
FOR WHITE LED APPLICATIONS
Pin Descriptions
Pin Name Pin Number Description
D8 1 Current sink input #8. Connected to VOUT when un-used.
D9 2 Current sink input #9. Connected to VOUT when un-used.
EN1 3 Enable Pin 1
EN3 4 Enable Pin 3
EN2 5 Enable Pin 2
PGND 6 Charge Pump Switch Ground
CN 7 Negative Terminal of Flying Capacitor
VIN 8 Input Power Supply. Requires 2.2F capacitor between this pin and ground.
CP 9 Positive Terminal of Flying Capacitor
NC 10,19 No-Connect
Charge pump output to drive load circuit. Requires 2.2F capacitor between this pin
V 11
OUT
and ground.
D1 12 Current sink input #1. Connected to V when un-used.
OUT
D2 13 Current sink input #2. Connected to V when un-used.
OUT
D3 14 Current sink input #3. Connected to V when un-used.
OUT
D4 15 Current sink input #4. Connected to V when un-used.
OUT
D5 16 Current sink input #5. Connected to V when un-used.
OUT
D6 18 Current sink input #6. Connected to V when un-used.
OUT
GND 17 Ground
D7 20 Current sink input #7. Connected to V when un-used.
OUT
GND EP PAD Exposed Pad (bottom). Connected to GND directly underneath the package.
Functional Block Diagram
2 of 10 January 2011
AL3158
Diodes Incorporated
www.diodes.com
Document number: DS35047 Rev. 2 - 2
NEW PRODUCT