Maxim Integrated has just introduced an innovative way of solving these problems by combining the latest advances in ultra-low power, mixed-signal IC technology with its fuel gauge algorithm called ModelGauge™ m5 EZ. This algorithm is built into the MAX1720x/MAX1721x ultra-low power stand-alone fuel gauge ICs. The MAX17201/MAX17211 monitor a single cell pack. The MAX17205/MAX17215 monitor and balance a 2S or 3S pack, or monitor a multiple-series cell pack. A Maxim 1-Wire® (MAX17211/MAX17215) or 2-wire I2C (MAX17201/MAX17205) interface provides access to data and control registers.
These fuel gauge ICs allow the system designer to simply walk through an easy-to-use Configuration Wizard in the evaluation kit software and generate a battery model suitable for their application without any complications related to custom battery characterization. The system designer needs to provide only three pieces of information:
1) what is the design capacity of the battery (often found on the label or data sheet of the battery);
2) what voltage per cell is to be considered as the empty point for the battery (depends on the application constraints); and
3) whether the battery charge voltage is above 4.275V (per cell in case of multiple series cells).
In addition to the battery model, the Configuration Wizard also walks the system designer through the various hardware configuration features such as:
- Battery pack schematics (relevant for multiple series cells)
- Number of series cells
- Shutdown mode (relevant if the battery is detached from the system)
- Sense resistor selection
- Temperature measurement – IC internal or using external thermistors
- Alerts based on various criteria like voltage, current, temperature, or battery state-of-charge (SOC %), over-current detection, alert polarity
- Battery life logging
- General purpose non-volatile memory usage
This eliminates the complicated and error-prone task of arranging various configuration bits manually by hand in order to prepare the registers for programming into the IC.