Patent ID: 8344710

Claim:
A method of operation for a DC-DC converter configured to supply power from a voltage source to an electrical load, the DC-DC converter including a first-stage boost converter coupled to the voltage source and a transformer-isolated second-stage buck converter coupled between an output of the first-stage boost converter and the electrical load, the method comprising the steps of: starting the DC-DC converter according to a prescribed sequence; determining a set voltage based on a prescribed output voltage and a maximum voltage conversion ratio of the second-stage buck converter; sampling the source voltage and comparing it to the set voltage; so long as the source voltage is above the set voltage, controlling the second-stage buck converter to provide both output voltage regulation under normal conditions and output current regulation under over-current conditions; and so long as the input voltage is below the set voltage, controlling the first-stage boost converter to provide output voltage regulation under normal conditions and limited output current regulation under over-current conditions, and controlling the second-stage buck converter to provide extended output current regulation independent of the input voltage under over-current conditions.