| 摘要 |
PROBLEM TO BE SOLVED: To inhibit capacity decline of a capacitor caused by parasitic capacitance of a semiconductor element.SOLUTION: In a voltage lower control circuit 10 which forms a DC-DC converter 16 provided in an IC 12, an end of a capacitor 36 for bootstrap is connected to an LX node 26A and the other end of the capacitor 36 is connected to a node 38B having higher potential than the LX node. In a transistor Ma, an N well 44 formed on a Psub is connected to the node 38B, and a P well 46 formed in the N well and a source S formed in the P well are connected to the LX node. With this configuration, parasitic capacitance between the N well and the P well of the transistor functions as electrostatic capacitance for bootstrap thereby to inhibit capacity decline of the electrostatic capacitance for bootstrap. |
