App note from IXYS on their battery operated surge voltage and inrush current protection circuit implementation. Link here (PDF)
Primary concerns with battery-operated devices include battery protection from inrush and short circuit currents caused by connected load, and load protection from voltage spikes when battery load dump occurs, which may cause significant voltage stress on electronic devices sharing the same battery as high current consumers.
Digital control allows designers to significantly simplify the design of protection devices, providing greater flexibility than hardware-only solutions. The device described in this application note is an example of implementing Zilog’s Z8F3281 microcontroller in power control.
This design, is intended to protect the battery from the inrush current and short circuitry at the load, and protect the load from voltage spikes from the battery, which are usually generated by fast battery load changing.