The Maxim MAX17048 and MAX17049 ICs are tiny, micropower current fuel gauges for lithium-ion (Li+) batteries in handheld and portable equipment. The MAX17048 operates with a single lithium cell and the MAX17049 with two lithium cells in series.
The ICs use the sophisticated Li+ battery-modeling algorithm ModelGauge™ to track the battery relative state-of-charge (SOC) continuously over widely varying charge and discharge conditions. The ModelGauge algorithm eliminates current-sense resistor and battery-learn cycles required in traditional fuel gauges. Temperature compensation is implemented using the system microcontroller.
The ICs automatically detect when the battery enters a low-current state and switches into a low-power 4 µA hibernate mode, while still providing accurate fuel gauging. The ICs automatically exit hibernate mode when the system returns to active state. On battery insertion, the ICs debounce initial voltage measurements to improve the initial SOC estimate, thus allowing them to be located on system side. SOC, voltage, and rate information is accessed using the I²C interface. The ICs are available in a tiny 0.9 mm × 1.7 mm, 8-bump wafer-level package (WLP), or a 2 mm × 2 mm, 8-pin TDFN package.
- Precision ±7.5 mV/cell voltage measurement
- ModelGauge algorithm
- Provides accurate state-of-charge
- Compensates for temperature/load variation
- Does not accumulate errors, unlike coulomb counters
- Eliminates learning
- Eliminates current-sense resistor
- Ultra-low quiescent current
- 4 µA hibernate, 23 µA active
- Fuel gauges in hibernate mode
- Automatically enters and exits hibernate mode
- MAX17048 uses 1 cell, MAX17049 uses 2 cells
- Battery-insertion debounce
- Reports charge and discharge rate
- Programmable reset for battery swap
- Configurable alert indicator
- Low SOC
- 1% change in SOC
- Battery undervoltage/overvoltage
- VRESET alert
- I²C interface