| 摘要 |
<P>PROBLEM TO BE SOLVED: To ensure that a power supply from a battery provided in a mobile terminal and a power supply obtained through the rectification of a carrier wave to a contactless IC card function are switched from one to the other, while limiting loss currents due to pulling-down. <P>SOLUTION: This loss current limiting circuit includes: a pull-down part 420 that sets the level of a signal line low when a signal line for a selection signal 414 is electrically opened; a switch part 430 that is inserted between the pull-down part and ground 422 for turning the pull-down part and the ground on and off; a power supply switch part 410 that switches a main power supply 412 and an auxiliary power supply 416 from one to the other according to the selection signal coming via the signal line; and an auxiliary power supply detection part 432 that detects that auxiliary power is being supplied. When the auxiliary power is not supplied, the switch part turns off, opening a pull-down resistance, and thus preventing loss currents. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
