| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an interface circuit that ensures communication quality without increase of a mounting area and cost increase accompanying it. <P>SOLUTION: When USB-BUS power supply voltage VBUS is not normally supplied to substrate gates of PMOS transistors 51, 53, 61, 63 constituting switches SW3-SW6, in a switch circuit 11 in an HS driver 5 that controls connection between a D+/RXD terminal and a D-/TXD terminal, and in a switch circuit 21 in an FS driver 6, a voltage obtained by amplifying power supply voltage DVDD for a core circuit is inputted into each of the substrate gates, and when the USB-BUS power supply voltage VBUS is normally supplied, stabilized power supply voltage VUSB for a USB is inputted into each of the substrate gates. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
