Patent ID: 6344758
Filing Date: 2002-02-05
Classification: H03K

Abstract:
The programmable logic device integrated circuit of comprising:a plurality of programmable elements, programmable configurable to implement logical functions, wherein the plurality of programmable elements produce logical signals compatible with a first voltage range between a first supply voltage and a reference voltage; a voltage shifter formed within the programmable logic integrated circuit, coupled to convert logical signals from the plurality of programmable elements to logical signals compatible with a second voltage range between a second supply voltage and the reference voltage, wherein the second supply voltage is above the first supply voltage; and an isolation device coupled between the plurality of programmable elements and the voltage shifter to isolate voltages above the first supply voltage from interfacing with the plurality of programmable elements, wherein the isolation device is a thick-oxide transistor having a voltage threshold about equal to or greater than a difference between the second voltage supply level and first voltage supply level, and a control electrode of the isolation device is coupled to the second supply voltage.