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Bridge Battery Backup Controllers for Notebooks

Reduce the Number of Backup (Bridge) Battery Cells in Notebooks with Backup Controller

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • Reduce Battery Size and Cost
  • Four Key Circuit Blocks
    • Adjustable Boost DC-DC Converter
    • NiCd/NiMH Trickle Charger
    • Always-On Linear Regulator (+28V Input)
    • Low-Battery Detector
  • Low 18µA Quiescent Current
  • Selectable Charging/Discharging Rates
  • Preset Linear-Regulator Voltage
    • 5V (MAX1612)
    • 3.3V (MAX1613)
  • 4V to 28V Main Input Voltage Range
  • Internal Switch Boost Converter
  • Small 16-Pin QSOP Package

Applications/Uses

  • Backup Battery Applications
  • Notebook Computers
  • Portable Equipment

Description

The MAX1612/MAX1613 manage the bridge battery (sometimes called a hot-swap or auxiliary battery) in portable systems such as notebook computers. They feature a step-up DC-DC converter that boosts 2-cell or 3-cell bridge-battery voltages up to the same level as the main battery. This voltage boosting technique reduces the number of cells otherwise required for a 6-cell plus diode-OR bridging scheme, reducing overall size and cost. Another key feature is a trickle-charge timer that minimizes battery damage caused by constant charging and eliminates trickle-charge current drain on the main battery once the bridge battery is topped off.

These devices contain a highly flexible collection of independent circuit blocks that can be wired together in an autonomous stand-alone configuration or used in conjunction with a microcontroller. In addition to the boost converter and charge timer, there is a micropower linear regulator (useful for RTC/CMOS backup as well as for powering a microcontroller) and a high-precision low-battery detection comparator.

The two devices differ only in the preset linear-regulator output voltage: +5.0V for the MAX1612 and +3.3V for the MAX1613. Both devices come in a space-saving 16-pin QSOP package.

Simplified Block Diagram

MAX1612, MAX1613: Typical Operating Circuit MAX1612, MAX1613: 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 .