| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a power supply circuit capable of controlling the execution of the discharge of an internal power supply voltage according to a duration of the lowering of external power supply potential. <P>SOLUTION: The power supply circuit includes: an external power supply potential detecting circuit 1 for detecting the potential of an external power supply VDD; a VAA power supply circuit 21 for generating an internal power supply voltage from the external power supply VDD, a VPP power supply circuit 22, a VDC power supply circuit 23 and a VINT power supply circuit 24; PMOS transistors P1, P2, P3 and P4 for stopping outputs of these internal power supply voltages; and a stop control circuit 3 of an internal power supply voltage for controlling the continuity of the PMOS transistors P1, P2, P3 and P4 based on a decision result when it is decided whether the duration of decline of the potential is shorter than a predetermined reference time or not, when the state of the potential of the external power supply VDD is lowered to the predetermined reference potential or lower is detected by the external power supply potential detecting circuit 1. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
