Patent ID: 8004806

Claim:
A protection device comprising: (a) a first current limiting load; (b) a second current limiting load; (c) a first circuit block being a depletion mode circuit with either a negative threshold voltage or a positive threshold voltage; (d) a second circuit block being a first enhancement mode circuit; and (e) a third circuit block being a second enhancement mode circuit, said third circuit block has a threshold voltage magnitude larger than said second circuit block; where said first circuit block, said second circuit block, and said third circuit block each has a drain terminal, a source terminal, and a gate terminal, said first circuit block connected in series with said second circuit block so that said source terminal of said first circuit block is connected to said drain terminal of said second circuit block, said drain terminal of said third circuit block is connected to said gate terminal of said second circuit block and further connected to said drain terminal of said second circuit block through said first current limiting load, said gate terminal of said third circuit block is connected to said drain terminal of said second circuit block through said second current limiting load, said gate terminal of said first circuit block is connected to said source terminals of said second circuit block and said third circuit block, a current path through said first circuit block and said second circuit block with said third circuit block controlling the ON and OFF status of said second circuit block and said second circuit block in turn controlling the ON and OFF status of said first circuit block.