| 摘要 |
<p>PURPOSE:To prevent the lowering of withstanding voltage against a high-voltage power supply terminal (a Vpp terminal), and to obviate even the breaking of a transistor by utilizing a diode having MOS structure and changing the breakdown voltage of the diode on the non-application of a power supply and on application thereof. CONSTITUTION:Breakdown voltage is brought to the lowermost value when gate voltage VG is zero V in a diode D1, with has structure, in which a source in the source and a drain for an MOS transistor is removed, and a gate thereof is controlled. That is, the gate is brought to zero V and broken down at low voltage and an internal circuit is protected from static electricity when a power supply is not applied, and the gate 4 is brought to supply potential and breakdown voltage is increased and the withstanding voltage of Vpp is improved when the power supply Vpp (such as 20V) is applied normally.</p> |
