Systems and methods for operating an uninterruptible power supply

A method for providing uninterrupted power from a power supply having a first input to receive input power and a UPS output from which UPS output power is provided, the method comprising:

• providing power from the first input to a first logic power supply having a first DC output when the input power at the first input is acceptable;
• providing the first DC output to a main logic power supply having an MLPS output;
• providing the MLPS output to a main controller and a communication circuit;
• turning on, with the main controller, a charger having a third DC output;
• providing the third DC output to the main logic power supply;
• turning off the first logic power supply;
• determining whether the charger is operating acceptably;
• if the charger is not operating acceptably, turning on the first logic power supply;
• and
• providing output power at the UPS output.

An uninterruptible power supply comprising:

• a first input to receive input power from an input power source;
• a backup power source having a DC output coupled to a common node;
• a UPS output configured to provide output power derived from at least one of the input power and power from the backup power source;
• a charger coupled to the backup power source through the common node;
• a main controller for controlling operation of the uninterruptible power supply;
• a communication circuit configured to allow a user to select a mode of operation of the uninterruptible power supply;
• a main logic power supply coupled to the common node and configured to receive power derived from the input power source, the charger, and the backup power source, and further configured to provide power to the main controller and the communication circuit;
• and
• means for providing power to the main logic power supply in a start up mode of operation from the input power bypassing the backup power source and the charger.