AAT3151

High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications


Please note: this product is being discontinued and is not recommended for new designs.

The AAT3151 is a low noise, constant frequency charge pump DC/DC converter that uses a tri-mode load switch (1X), fractional (1.5X), and doubling (2X) conversion to maximize efficiency for white LED applications. The AAT3151 is capable of driving four white LEDs at a total of 120mA from a 2.7V to 5.5V input. The current sinks may be operated individually or in parallel for driving higher-current LEDs. A low external parts count (two 1μF flying capacitors and two small 1μF capacitors at VIN and VOUT) makes the AAT3151 ideally suited for small battery-powered applications.

AnalogicTech’s AS2Cwire™ (Advanced Simple Serial Control™) serial digital input is used to enable, disable, and set current for each LED with a 16-level logarithmic scale plus four low-current settings down to 50μA for optimized efficiency, with a low housekeeping current ofonly 50μA.

The charge pump output of the AAT3151 is equipped with built-in protection for VOUT. Each current sink input has short circuit and auto-disable to guard against LED failure conditions. Built-in soft-start circuitry prevents excessive inrush current during start-up. A low-current shutdown feature disconnects the load from VIN and reduces quiescent current to less than 1μA.

The AAT3151 is available in a Pb-free, space-saving, thermally-enhanced, 12-pin 3x3mm TDFN package, or in the lower-profile STDFN package.

Please note: AAT3151 is not recommended for new designs.

Specifications

Number of LEDs4
LED Channels4
LED(s) per/Ch1
Min. VIN (V)2.7
Max. VIN (V)5.5
InterfaceAS2Cwire™
Typ. IQ (μA)50
Peak Efficiency97%
Current Accuracy (%)±10%
Current Matching (%)±0.5%
Max. IOUT per/Ch (mA)30
Package (mm)3 x 3
PackageSTDFN33-12,TDFN33-12

Features

  • VIN Range: 2.7V to 5.5V
  • Fully Programmable Current with Single Wire
  • 16-Step Logarithmic Scale
  • 15/20/30mA Max Current
  • Four Low-Current Settings Down to 50μA
  • Low IQ (50μA) for Low-Current Mode
  • Tri-Mode 1X, 1.5X, and 2X Charge Pump for Maximum Efficiency and VF Coverage
  • Drives Four Channels of LEDs
  • Individual Main/Sub-Group Control
  • No Inductors, Low Noise Operation
  • 1MHz Constant Switching Frequency
  • Small Application Circuit
  • Built-In Thermal Protection
  • Built-In Auto-Disable for Short-Circuit
  • Automatic Soft Start
  • IQ <1μA in Shutdown
  • TDFN33-12 or STDFN33-12 Package

Product Documents