Time compensated current ramp for resonant power converters

摘要

A current mode controller for a series resonant power converter having a primary current, a conduction time and a pulse width modulator controller is disclosed. The current mode controller having a current ramp generator in electrical communication with the primary current and being operative to generate a current ramp having a voltage proportional to the primary current. A voltage ramp generator is in electrical communication with the power converter and operative to generate a voltage ramp. The current mode controller further includes a multiplier in electrical communication with the current ramp generator and the voltage ramp generator. The multiplier being operative to generate a time-dependent current ramp having an amplitude proportional to the conduction period of the power converter. A limited voltage ramp generator operative to generate a limited voltage ramp is in electrical communication with the voltage ramp generator. In this respect, the current mode controller further includes an adder in electrical communication with the limited voltage ramp generator and the multiplier and operative to generate a controlling ramp proportional to the limited voltage ramp and the time-dependent current ramp. As such, the adder is in electrical communication with the pulse width modulator controller such that the controlling ramp controls the conduction period of the power converter.