US Patent 7701264 Semiconductor output circuit

To improve a depletion transistor provided between a control terminal of an output transistor and an output terminal coupled to a load not to enter a conductive state when the output transistor is in the conductive state. The output transistor is served as a source follower. Control voltages which controlling the conductive state/nonconductive state of the depletion transistor are supplied to both a control terminal (gate) and a substrate terminal (back gate) of the depletion transistor.