Circuit for protecting the input/output stage of a low voltage integrated circuit device from a failure of the internal voltage supply or a difference in the power-up sequencing of supply voltage levels

摘要

A circuit for protecting internal logic circuits of an integrated circuit (IC) device from a failure of internal voltage supply is disclosed. A protection circuit is connected between the internal power supply and an external power supply. The protection circuit reduces the external power to the internal logic circuits. A pass circuit is connected to the protection circuit and the internal power supply. The pass circuit is configured to reduce the input voltage difference in the protection circuit in the event of a failure of the internal power supply to prevent a failure of the protection circuit. The voltage level of the external power supply is typically higher than the internal supply voltage level, and exposure to the full external voltage level may disable the protection circuit.