Two stage structure for power delivery adapter

A method for providing an output voltage comprising:

• receiving an alternating current (AC) voltage from an AC power source;
• generating a first voltage based on the AC voltage, the first voltage being a full-wave rectified voltage;
• generating, by a first power stage, a second voltage based on the first voltage, the second voltage being a lower rectified voltage that is less than the first voltage;
• receiving, by a power delivery adapter controller, at least one input indicative of a requested voltage value;
• controlling, by the power delivery adapter controller, a switch that switches a resistor in and out of a feedback control circuit based on the received at least one input indicative of the requested voltage value;
• receiving, by a second power stage comprising a buck converter and a buck controller operatively coupled to the buck converter, the second voltage;
• generating, by the feedback control circuit, a feedback control input based on the at least one input indicative of the requested voltage value;
• controlling, by the buck controller, a duty cycle of an output control signal based on the feedback control input;
• and
• generating, by the buck converter, an output voltage equal to the requested voltage value based on the received second voltage and the duty cycle of the output control signal received from the buck controller.

A power adapter comprising:

• a rectifier;
• a cable including a plug connected to an alternating current (AC) power source, the AC power source providing an AC voltage to the rectifier;
• a power delivery adapter controller;
• a multipurpose port;
• and
• a two-stage adapter circuit including a first power stage and a second power stage,
• the first power stage configured to receive a first voltage generated by the rectifier and based on the AC voltage, and configured to output a second voltage;
• the second power stage comprising a buck converter and a buck controller operatively coupled to the buck converter and wherein the buck converter is configured to receive the second voltage and configured to convert the second voltage to a third voltage;
• and
• the power delivery adapter controller configured to receive at least one input indicative of a requested voltage value from the multipurpose port and configured to provide at least one output;
• and
• a feedback control circuit configured to provide a feedback control input to the buck controller, the feedback control input being based on the at least one output provided by the a power delivery adapter controller, the buck controller configured to control a duty cycle of an output control signal based on the feedback control input, wherein the at least one output provided by the a power delivery adapter controller controls a switch that switches a resistor in and out of the feedback control circuit, and wherein the buck converter is configured to determine a value for the third voltage based on the duty cycle of the output control signal received from the buck controller and to provide the third voltage to the multipurpose port.