Method and apparatus to charge power assist unit

A method, comprising:

• providing, by a power supply unit, a power rail to power a load of an information handling system;
• providing a constant current indication that indicates whether the power supply unit is operating in a constant current mode;
• providing, by the power supply unit, a current level indication of a current supplied by the power supply unit to the load;
• receiving, by a controller of a power assist unit coupled to the power rail, an enable signal when the first constant current indication indicates that the first power supply unit is operating in the constant current mode;
• receiving, by the controller, the current level indication in response to receiving the enable signal;
• determining that the current level indication is greater than a first threshold level in further response to receiving the enable signal;
• controlling, by the power assist unit, a converter of the power assist unit to provide a current to the power rail from a power storage element of the power assist unit at a first current level to meet an additional demand of the load for power when the controller receives the enable signal and when the current level indication is greater than a first threshold level;
• controlling the converter to charge the power storage element from the power rail when the controller does not receive the enable signal;
• determining if the amount of current supplied to the load is greater than a second threshold level based upon the current level indication when the controller does not receive the enable signal;
• directing the converter to charge the power storage element at a second current level when the amount of current supplied to the load is greater than the second threshold level;
• directing the converter to charge the power storage element at a third current level when the amount of current supplied to the load is less than the second threshold level, the third current level being greater than the second current level;
• wherein, when the controller directs the converter to charge the power storage element at the third current level, the third current level is less than a maximum current level;
• and
• wherein the maximum current level is determined based upon an inventory of load elements of the information handling system and a state in which the information handling system is operating.

A power assist unit of an information handling system, the power assist unit comprising:

• a power storage element;
• a converter coupled to the power storage element and to a power rail to a load of the information handling system;
• a controller configured to:
• receive an enable signal when a constant current indication indicates that a power supply unit is operating in a constant current mode, wherein the controller is further configured to determine that a current level indication from the power supply unit is greater than a first threshold level and in response to direct the converter to provide a first current to the power rail from the power storage element to meet an additional demand of the load for power;
• wherein, when the controller does not receive the enable signal, the controller is further configured to direct the converter to charge the power storage element from the power rail;
• wherein the controller is further configured, when the controller does not receive the enable signal, to direct the converter to charge the power storage element at a second current level when the current level indication is greater than a second threshold level;
• wherein when the current level indication is less than the second threshold level, the controller is further configured to direct the converter to charge the power storage element at a third current level, the third current level being greater than the second current level;
• wherein when the controller directs the converter to charge the power storage element at the third current level, the third current level is less than a maximum current level;
• and
• wherein the maximum current level is determined based upon an inventory of load elements of the information handling system and a state in which the information handling system is operating.