Power supply apparatus with step-up and step-down conversion

A power supply apparatus with step-up and step-down conversion, comprising:

• a primary-side rectifying/filtering circuit, configured to receive an AC input voltage, and rectify and filter the AC input voltage into a DC input voltage,
• a step-up converter, coupled to the primary-side rectifying/filtering circuit, and configured to receive the DC input voltage,
• a full-bridge LLC converter, coupled to the step-up converter,
• a primary-side controller, coupled to the step-up converter and the full-bridge LLC converter, and configured to provide a step-up control signal to control the step-up converter to step up the DC input voltage into a step-up voltage, and provide a conversion control signal to control the full-bridge LLC converter to convert the step-up voltage into a conversion voltage according to at least one gain condition,
• a secondary-side rectifying/filtering circuit, coupled to the full-bridge LLC, and configured to receive the conversion voltage, and rectify and filter the conversion voltage into a DC output voltage,
• a voltage regulator, coupled to the secondary-side rectifying/filtering circuit, and
• a secondary-side controller, coupled to the voltage regulator and the primary-side controller, and configured to receive a power demand signal provided from a load, control the primary-side controller to provide the step-up control signal and the conversion control signal according to the power demand signal, and provide a voltage regulation signal to control the voltage regulator so as to regulate the DC output voltage to an output voltage for supplying power to the load,
• wherein the secondary-side controller provides a feedback control signal to the primary-side controller, wherein the feedback control signal comprises a step-up conversion feedback control signal and a full-bridge LLC conversion feedback control signal,
• wherein the primary-side controller adjusts the step-up control signal according to the step-up conversion feedback control signal, and adjusts the conversion control signal according to the full-bridge LLC conversion feedback control signal so as to adjust the at least one gain condition.