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High-Efficiency, 26V Step-Up Converters for Two to Six White LEDs

26V, Step-Up DC-DC Powers Up to 6 White LEDs with Up to 87% Efficiency

Product Details

Key Features

Parametric specs for LED Drivers
VIN (V) (min) 2.6
VIN (V) (max) 5.5
Max. No. of LEDs 6
# LED Channels 1
Regulation Topology Inductor Based
Battery Input 1-Cell Li+
LED Configuration Series
ILED per Channel (A) (max) 0.02
PWM Dimming Freq. (kHz) (max) 200
Dimming Control Analog
PWM
VCURR_SENSE (mV) 100
POUT (W) 0.9
ICC (mA) (max) 0.55
LED String Volt. (V) (max) 26
Switching Frequency (kHz) 500
Package/Pins TDFN/8
Budgetary
Price (See Notes)
0
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Simplified Block Diagram

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Parameters

Parametric specs for LED Drivers
VIN (V) (min) 2.6
VIN (V) (max) 5.5
Max. No. of LEDs 6
# LED Channels 1
Regulation Topology Inductor Based
Battery Input 1-Cell Li+
LED Configuration Series
ILED per Channel (A) (max) 0.02
PWM Dimming Freq. (kHz) (max) 200
Dimming Control Analog
PWM
VCURR_SENSE (mV) 100
POUT (W) 0.9
ICC (mA) (max) 0.55
LED String Volt. (V) (max) 26
Switching Frequency (kHz) 500
Package/Pins TDFN/8
Budgetary
Price (See Notes)
0

Key Features

  • Accurate Current Regulation for Uniform Illumination
  • High Efficiency Up to 87%
  • Flexible Analog or PWM Dimming Control
  • Up to 900mW Output Power with Internal 30V MOSFET Switch
  • Fast 1MHz (MAX1561) or 500kHz (MAX1599) PWM Operation
  • Small, Low-Profile External Components
  • 2.6V to 5.5V Input Range
  • 26V (max) Output with Overvoltage Protection
  • Optimized for Low 15mVP-P Input Ripple
  • Soft-Start with Zero Inrush Current
  • 0.3µA Shutdown Current
  • Tiny 8-Pin 3mm x 3mm Thin DFN Package

Applications/Uses

  • Cell Phones/Smartphones
  • e-Books and Subnotebooks
  • PDAs, Palmtops, and Wireless Handhelds
  • White LED Display Backlighting

Description

The MAX1561/MAX1599 step-up converters drive up to six white LEDs with a constant current to provide backlight in cell phones, PDAs, and other hand-held devices. The step-up converter topology allows series connection of the white LEDs so the LED currents are identical for uniform brightness. This configuration eliminates the need for ballast resistors and expensive factory calibration.

The MAX1561/MAX1599 include an internal, high-voltage, low-RDS(ON) N-channel MOSFET switch for high efficiency and maximum battery life. A single Dual Mode™ input provides a simple means of brightness adjustment and on/off control. Fast 1MHz (500kHz for the MAX1599) current-mode, pulse-width modulated (PWM) operation allows for small input and output capacitors and a small inductor while minimizing ripple on the input supply/battery. Programmable soft-start eliminates inrush current during startup.

Both devices are available in a space-saving, 8-pin 3mm x 3mm thin DFN package with exposed paddle (EP).

Simplified Block Diagram

MAX1561, MAX1599: Typical Operating Circuit MAX1561, MAX1599: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .