| 摘要 |
<p>PROBLEM TO BE SOLVED: To protect the internal circuit of a step-up circuit from overvoltage, such as an electrostatic voltage applied to a capacitor connection terminal. SOLUTION: NMOS transistors MN21 and MN22, whose sources and gates are connected in common and which have snapping back voltages lower than the withstanding voltages of other transistors are connected between the respective connection terminals of an external connection capacitor C1 and a low potential power supply terminal 3. Further, an NMOS transistor MN23 whose source and drain are connected in common and which has a snapping back voltage lower than the withstanding voltages of other transistors is connected between the respective connection terminals of external connection capacitor C2.</p> |
