Patent ID: 6586984
Filing Date: 2003-07-01
Classification: H03K

Abstract:
A circuit configured to receive a source voltage and a pad voltage, said circuit comprising: a first input for receiving the source voltage; a second input for receiving the pad voltage; at least one band-limiting resistor connected to the first input and having a resistance which provides that said at least one band-limiting resistor band-limits the source voltage; at least one band-limiting resistor connected to the second input and having a resistance which provides that said at least one band-limiting resistor band-limits the pad voltage; at least one source-follower transistor connected to the first input to source-follow down the source voltage; at least one source-follower transistor connected to the second input to source-follow down the pad voltage; a comparator which receives said source voltage and said pad voltage and compares the two to determine when an over-voltage condition exists; and at least one resistor connected to the source-follower transistor which is connected to the second input and having a resistance which provides that an offset is introduced to said pad voltage before said pad voltage is provided to said comparator.