High voltage tolerant off chip driver circuit

摘要

An off chip driver circuit includes a pre-driver circuit and a driver circuit. Driver data and enable inputs are decoded in the pre-driver circuit to provide independent inputs to pull up and pull down transistors in the driver circuit. The enable input keeps the driver circuit in the active or high impedance modes. A feedback signal generated by the driver output and the driver enable signals controls an inverter circuit within the driver circuit to provide proper biasing conditions at the gate of the pull up transistor. This feed back provides fast switching times for the driver circuit and prevents gate oxide of all the transistors from being overstressed by the external high voltage signal.