| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To prevent momentary disconnection of power, when switching from a battery to a USB power source. <P>SOLUTION: A negative electrode of a secondary battery 26 is grounded via a switch S3 and is grounded via mechanical switches DC SW and USB SW. In a state where an MD set 1 is being operated by the power of the secondary battery 26, when a USB plug is inserted, the switch USB SW is turned off. Since the switch S3 is turned on, a set supply power source is still a battery power source. After a personal computer and a system controller 21 carry out enumeration and supply of specific power is allowed, the switch S3 is turned off, and a DC-DC converter 25a is turned on. As a result, a switch-over from the battery power source to the USB power source is carried out. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
