An LED backlight driving circuit has a voltage converting unit having an output terminal connected to a positive electrode of an LED to provide a driving voltage required by the LED, a driving unit to control the voltage converting unit to achieve a voltage conversion, and a protection unit connected in series between a negative electrode of the LED and the driving unit. The media enhances denitrification of effluent that has been recycled from the nitrification unit to the anoxic tank. The pixels in the blocks which are determined to be a binary image block are all determined to be pixels of a binary image while the pixels in the blocks which are determined to be a tone image block are all determined to be pixels of a tone image. The integrated pointing device is configured to transmit a signal to the base in response to physical manipulation by a user. Distractions are identified while the work is being monitored. That is, a phase shift region is changed into a phase non-shift region, and the phase non-shift region is changed into the phase shift region.