| 摘要 |
<p>PROBLEM TO BE SOLVED: To minimize a power source and to effectively save the power, by supplying operating electric power to a display device through a universal serial bus and stopping the power supply to the display device when a power- saving mode is instructed by a computer. SOLUTION: A rectification part 51 rectifies AC power of the display device. A main SMPS(switching mode power supply) 52 switches and rectifies the voltage of the rectification part 51, and then supplies the electric power to a monitor circuit (display device). An auxiliary SMPS 53 supplies the electric power to a microcomputer 54 when no electric power is supplied from the USB (universal serial bus) hub 10. The USB hub 10 supplies 5V from the computer to a power cutoff device 200 through the USB cable. The auxiliary SMPS 53 supplies the electric power to the microcomputer 54 when the electric power is not supplied from the USB hub 10. Consequently, the electric power can effectively be saved.</p> |
