Abstract: The present disclosure discloses an LLC resonant converter and a method for suppressing ripples in output voltage of the LLC resonant converter. The LLC resonant converter comprises: a half-bridge or full-bridge chopper having a driving circuit, an inductance-capacitance series resonant network coupled to the chopper, an isolation transformer coupled to the resonant network, and a rectification and filtering circuit coupled to the isolation transformer; a feedforward controller coupled to generate a feedforward signal based on an input voltage; and a controlled oscillator coupled to receive the feedforward signal from the feedforward controller and to control an operating frequency of the chopper via the driving circuit based on the feedforward signal. Thus, a feedforward correction is provided for the LLC resonant converter, so that ripples in a DC output voltage of the LLC resonant converter are reduced.

Abstract: Example isolated AC-DC power supplies include a PFC converter coupled to an AC input, a DC-DC converter coupled between the PFC converter and a DC output, and a controller configured to control switching operation of the DC-DC converter. A pulse modulator is coupled to an output of the PFC converter to receive a signal representative of voltage ripple at the output of the PFC converter, and is configured to modulate a pulse signal based on an amplitude of the voltage ripple. A pulse demodulator is coupled to the pulse modulator to receive the modulated pulse signal, and is configured to demodulate the modulated pulse signal and provide a demodulated signal to adjust switching operation of the DC-DC converter. Also disclosed are methods for controlling isolated AC-DC power supplies.

Abstract: The present disclosure discloses an LLC resonant converter and a method for suppressing ripples in output voltage of the LLC resonant converter. The LLC resonant converter comprises: a half-bridge or full-bridge chopper having a driving circuit, an inductance-capacitance series resonant network coupled to the chopper, an isolation transformer coupled to the resonant network, and a rectification and filtering circuit coupled to the isolation transformer; a feedforward controller coupled to generate a feedforward signal based on an input voltage; and a controlled oscillator coupled to receive the feedforward signal from the feedforward controller and to control an operating frequency of the chopper via the driving circuit based on the feedforward signal. Thus, a feedforward correction is provided for the LLC resonant converter, so that ripples in a DC output voltage of the LLC resonant converter are reduced.