| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To easily constitute a charging system very efficiently which selects USB bus power supply and AC adapter power supply as power supply for charging. <P>SOLUTION: When charged by the USB bus power supply, a constant-current control circuit 16 which controls a current is arranged at a charger 2 side, while when charged by the AC adapter power supply, a constant-current control portion 6 which controls the current is arranged at a BHT3 side. A CPU18 of the charger 2 supplies the AC adapter power supply to a feeding point 15 preferentially, when both of the AC adapter 12 and the USB bus 13 are connected to the charger 2. Moreover, power supply switching circuits 14, 17 to supply both of the power supply to the feeding point 15 are constituted by connecting two P channel FETs in series. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
