A device and method for controlling a power converter. The device includes an activation terminal configured to obtain a first voltage based on the input voltage; a controlling terminal configured to obtain a second voltage based on the output voltage; and a digital controller configured to obtain a driving power based on the first voltage and/or the second voltage; the digital controller is configured to obtain the driving power at least based on the first voltage when the power converter is stopped. Therefore, a sufficient driving power can be provided for the digital controller even when the power converter is stopped.