General 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.

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

Notebook Computers

Portable Equipment

Backup Battery Applications