Patent ID: 7456441

Claim:
A circuit for carrying current between a first circuit node and a second circuit node in a manner that is different depending on a state of the circuit, the state being dependent on a voltage at either or both of the first circuit node and the second circuit node, the circuit comprising: a first well having a first polarity and coupled to the first circuit node through a first parallel combination of a first contact region having the first polarity and a second contact region having a second polarity that is opposite the first polarity, wherein a net dopant density of each of the first and second contact regions is higher than a net dopant density of the first well, wherein the first contact region is coupled to the first circuit node through a resistor circuit element; and a second well having the first polarity and separated from the first well by an intervening region of the second polarity, the second well being coupled to the second circuit node through a second parallel combination of a third contact region having the first polarity and a fourth contact region having the second polarity, wherein a net dopant density of each of the third and fourth contact regions is higher than a net dopant density of the second well.