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White LED Current Regulator with 1x/1.5x High-Efficiency Charge Pump

Product Details

Key Features

Parametric specs for LED Drivers
VIN (V) (min) 2.7
VIN (V) (max) 5.5
Max. No. of LEDs 5
# LED Channels 5
Regulation Topology Charge Pump
Battery Input 1-Cell Li+
LED Configuration Parallel
ILED per Channel (A) (max) 0.03
PWM Dimming Freq. (kHz) (max) 5
Dimming Control Digital
PWM
POUT (W) 0.7
ICC (mA) (max) 3.5
LED String Volt. (V) (max) 5
Switching Frequency (kHz) 1000
Package/Pins TQFN/16
Budgetary
Price (See Notes)
2.3
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Simplified Block Diagram

Technical Docs

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Parameters

Parametric specs for LED Drivers
VIN (V) (min) 2.7
VIN (V) (max) 5.5
Max. No. of LEDs 5
# LED Channels 5
Regulation Topology Charge Pump
Battery Input 1-Cell Li+
LED Configuration Parallel
ILED per Channel (A) (max) 0.03
PWM Dimming Freq. (kHz) (max) 5
Dimming Control Digital
PWM
POUT (W) 0.7
ICC (mA) (max) 3.5
LED String Volt. (V) (max) 5
Switching Frequency (kHz) 1000
Package/Pins TQFN/16
Budgetary
Price (See Notes)
2.3

Key Features

  • Excellent 0.3% LED-to-LED Current Matching
  • 30mA/LED Drive Capability
  • Proprietary 1x/1.5x Modes for Ultra-High Efficiency
  • Low Input Ripple and EMI
  • Eliminates Ballast Resistors
  • Digital or PWM LED Dimming Control
  • 0.1µA Shutdown Current
  • 2.7V to 5.5V Supply Voltage Range
  • Soft-Start Limits Inrush Current
  • Thermal-Shutdown Protection
  • No External Inductor, Schottky, or Zener Diode Required
  • Tiny 16-Pin 4mm x 4mm Thin QFN Package

Applications/Uses

  • Cell Phones/Smartphones
  • Digital Cameras and Camcorders
  • PDAs and Palmtop Computers
  • Portable MP3 Players
  • White LED Backlighting

Description

The MAX1570 fractional charge pump drives up to five white LEDs with regulated constant current for uniform intensity. The MAX1570 maintains the highest possible efficiency over the full 1-cell lithium-ion (Li+) battery input voltage range by utilizing a 1x/1.5x fractional charge pump and very-low-dropout current regulators. The MAX1570 operates with 1MHz fixed-frequency switching, allowing for tiny external components. The regulation scheme is optimized to ensure low EMI and low input ripple.

An external resistor sets the full-scale LED current, while two digital inputs control on/off and select between three levels of brightness. A pulse-width modulation (PWM) signal can also be used to modulate LED brightness.

The MAX1570 is available in 16-pin 4mm x 4mm Thin QFN packaging (0.8mm max height).

Simplified Block Diagram

MAX1570: Typical Operating Circuit MAX1570: 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 .

Sampling:
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.