Switching circuit utilizing a high voltage transistor protection technique for integrated circuit devices incorporating dual supply voltage sources

摘要

A switching circuit incorporating a high voltage transistor protection technique for use in an integrated circuit device having dual voltage supplies which extends the maximum pumped voltage ("VCCP") for reliable MOS transistor operation to VCCP=VTN+(2*VCC), where VTN is the threshold voltage of the transistor and VCC is the supply voltage level. This is effectuated by adding an additional relatively thick gate oxide transistor in series with the relatively thin gate oxide MOS N-channel transistors in a conventional high voltage switching circuit to increase the reliable maximum voltage for the high voltage power supply.