A self-oscillating DCM is disclosed comprising two inductors that charge and discharge 180 degrees out of phase such that the charging inductor is conducting an upward ramping current and the discharging inductor is conducting a downward ramping current. Each sensor element includes a photo-sensing element coupled to a single amplifier. The differencing processing unit performs a difference operation on at least two tree-structured documents, in accordance with difference configuration information regarding the documents. The deactivation can be performed in sequence from the highest-level components to the lowest-level components to ensure that components that are needed by other components are not prematurely deactivated. The conductive wires are used to connect electrically the LED with the printed circuit board.