When the main supply is present and above theminimum system supply voltage, the regulator operates in buck mode and charges the storage element at up to500mA peak inductor current. Once the storage element is charged, the circuit draws only 2.5μA of current while it maintains the super capacitor or other storage element in its ready state. When the main supply is removed, the regulator operates in boost mode and prevents the system from dropping below the minimum operating voltage, discharging the storage element at up to 2.5A peak inductor current.

The MAX38888 is externally programmable for minimum and maximum voltage of the storage element, such as super capacitor, minimum system voltage, and maximum charge and discharge currents.