| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a DC/DC converter that reduces power consumption and can start in a short time. <P>SOLUTION: A voltage V<SB POS="POST">CC</SB>generated at a second output capacitor Co2 is input into a power terminal VCC. An input voltage V<SB POS="POST">IN</SB>is input into a high voltage terminal VH. A charging transistor M2 is an N-channel MOSFET (Metal Oxide Semiconductor Field Effect Transistor) disposed between the high voltage terminal VH and the power terminal VCC and biased to be normally on. A current limiting circuit 40 limits a charge current I<SB POS="POST">CHG</SB>flowing from the high voltage terminal VH to the power terminal VCC in a first state in which the voltage V<SB POS="POST">CC</SB>at the power terminal VCC is lower than a first predetermined threshold voltage V<SB POS="POST">TH1</SB>, and lowers the charge current I<SB POS="POST">CHG</SB>substantially to zero in a second state in which the voltage V<SB POS="POST">CC</SB>is higher than a second threshold voltage V<SB POS="POST">TH2</SB>. <P>COPYRIGHT: (C)2012,JPO&INPIT |
