Patent ID: 8879279

Claim:
An LLC resonant power converter system comprising: a transformer comprising a primary inductor and a secondary inductor; a switch control stage configured to generate a plurality of switching signals having a duty-cycle; an input stage comprising the primary inductor and a plurality of switches that are controlled in response to the respective plurality of switching signals to generate a primary resonant current; an output stage comprising the secondary inductor and being configured to conduct an output current through a load based on a secondary resonant current to generate an output voltage; and a controller configured to control the duty cycle of the plurality of switching signals to limit the output current to a predetermined magnitude in response to variations of the load, wherein the controller comprises: a voltage loop controller configured to generate a signal defining a period of the plurality of switching signals based on a difference between a reference voltage and the output voltage; a pulse-width modulation (PWM) controller configured to control the duty-cycle of the plurality of switching signals based on the period; a current loop controller configured to generate a current difference signal based on a difference between a reference current and the output current; and a dead-time controller configured to define a switching dead-time for the plurality of switches based on the current difference signal, the switching dead-time being provided to the PWM controller to set the switching dead-time of the plurality of switching signals to limit the output current to the predetermined magnitude.