Powering microcontrollers

Abstract

This application relates to methods and apparatus for powering microcontrollers (), in particular for powering microcontrollers of a personal care product, such as a shaver product (). The microcontroller is arranged such that a first output port (-) of a plurality of output ports of the microcontroller receives, in use, an AC waveform. Each output port has an associated high-side switch () electrically connected between the output port and a high-side DC voltage rail and an associated low-side switch () electrically connected between the output port and a low-side DC voltage rail. A processing module () of the microcontroller is configured to monitor a phase of the AC waveform and to control switching of the associated high-side and low-side switches of the first output port based on the phase of the AC waveform so as to provide a rectified voltage between the high-side DC voltage rail and the low-side voltage rail for powering the processing module. The processing module () also controls switching of the associated switches of at least a further output port to output a control signal for controlling at least one aspect of operation of a host device. The processing module is further configured to maintain the associated high-side switch of the first output port in a turned-off state when a monitored voltage of the AC waveform at the first output port is between zero and a monitored voltage at the high-side DC voltage rail, and to maintain the associated high-side switch of the first output port in a turned-on state when the monitored voltage of the AC waveform at the first output port is greater than the monitored voltage at the high-side DC voltage rail.