The MAX1660 digitally controlled fuel-gauge interface executes two essential functions for rechargeable battery-pack management: fuel gauging and pack overcurrent protection. It accurately monitors a battery pack's charge and discharge current flow, and records each using two independent, on-board Coulomb counters. Each counter's contents are externally accessible via a System Management Bus (SMBusTM)-compatible 2-wire serial interface. An optional third wire interrupts the microcontroller (C) when the charge or discharge counters reach a preset value, or when an overcurrent condition (charge or discharge) occurs. In the event of an overcurrent or short-circuit condition, the MAX1660 disconnects the load and alerts its host. The MAX1660's flexibility allows accurate fuel gauging for any battery chemistry, using any desired control algorithm.