| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a step-up/down converter using an n type MOSFET on a high side which implements a step-up mode more easily. <P>SOLUTION: A step-up/down converter 100 includes: a step-down section 102 for turning on/off a high side n type MOSFET 134 to generate a driving voltage Vd lower than a battery voltage Vbat in a step-down mode; a step-up section 104 for turning on/off a low side n type MOSFET 128 to generate a driving voltage Vd higher than the battery voltage Vbat in a step-up mode; a charging section 142 for charging a bootstrap capacitor 114 by means of the on/off action of the low side n type MOSFET 128 in the step-up mode; and a high side switch drive section 138 for applying a voltage Vb at an end 114b of the charged bootstrap capacitor 114 to a gate of the high side n type MOSFET 134 in the step-up mode. <P>COPYRIGHT: (C)2013,JPO&INPIT |
