The MAX1538ETI selector provides power-source control for dual-battery systems. The device selects between an AC adapter and dual batteries based on the presence of the three power sources and the state of charge of each battery. The MAX1538ETI includes analog comparators to detect AC/airline-adapter presence and determine battery undervoltage. Fast analog circuitry allows the device to switch between power sources to implement a break-before-make time, which allows hot swapping of battery packs. The MAX1538ETI independently performs power-source monitoring and selection, freeing the system power-management μP for other tasks. This simplifies the development of μP power-management firmware and allows the μP to enter standby, reducing system power consumption. The MAX1538ETI supports “relearn mode,” which allows the system to measure and fully utilize battery capacity. In this state, the part allows the selected battery to be discharged even when an AC adapter is present. The MAX1538ETI can also be used to power the system in an aircraft. On detecting an airline adapter, the MAX1538ETI automatically disables charging or discharging of battery packs and only allows the system to be powered from the adapter. The MAX1538ETI is available in a space-saving 28-pin thin QFN package with a maximum footprint of 5mm x 5mm.
Feature
- Automatically Detects and Responds to:
- Low-Battery Voltage Condition
- Battery Insertion and Removal
- AC-Adapter Presence
- Airline-Adapter Presence
- Step-Down and Step-Up Charger Compatibility
- Fast Break-Before-Make Selection
- Allows Hot Swapping of Power Sources
- No External Schottky Diodes Needed
- 50μA Maximum Battery Quiescent Current
- Implements Battery Capacity Relearning
- Allows Usage of Aircraft Supply
- Direct Drive of P-Channel MOSFETs
- Simplifies Power-Management μP Firmware
- 4.75V to 28V AC-Adapter Input Voltage Range
- Small 28-Pin Thin QFN Package (5mm x 5mm)
Applications
- Dual-Battery Portable Equipment
- Internet Tablets
- Notebook and Subnotebook Computers
