Apple Inc.
Power converter with output voltage control

Abstract:

A variable-output power converter includes a switch-mode voltage conversion stage operating in a peak-current control mode. For example, the timing of the turn-off of a MOSFET associated with a buck converter can be adjusted based on a measurement of current conducted through the by MOSFET. When the current through the MOSFET exceeds a threshold, the MOSFET is turned off, thereby defining the peak current that can be output by the variable-output power converter. The peak-current threshold can be adjusted by changing one or more characteristics of a compensation network configured to provide positive feedback to the variable-output power converter. In many examples, the peak-current threshold is adjusted using a pulse-width modulated signal.