A system and method for operating system power management in a computing device for power over Ethernet. The sensor includes including a photoelectric conversion unit configured to generate a charge, a first transfer unit configured to transfer the generated charge from the to an output unit, and the output unit transfers the charge to an outside of the sensor, and a second transfer unit configured to transfer the charge from the first transfer unit to a drain unit to drain the charge. More preferably, such constituent shares at least 90% homology.