Patent ID: 7411172

Claim:
An apparatus comprising a latch circuit which includes: first and second resonant tunneling devices coupled in series with each other between first and second nodes; a reset portion coupled to said first and second nodes, said reset portion including a photodiode portion responsive to varying photonic energy for switching between first and second states which are different, wherein when said photodiode portion is in said first state said reset portion normalizes a voltage across each of said resonant tunneling devices; a first terminal to which is applied a first voltage, and a second terminal to which is applied a second voltage less than said first voltage; and wherein said reset portion includes a first resistive element coupled between said first terminal and a first end of said photodiode portion, a first capacitive element coupled between said first node and said first end of said photodiode portion, a second resistive element coupled between said second terminal and a second end of said photodiode portion, and a second capacitive element coupled between said second node and said second end of said photodiode portion; a first bias terminal to which is applied a first bias voltage; a second bias terminal to which is applied a second bias voltage different from said first bias voltage; a third resistive element coupled between said first bias terminal and said first node; and a fourth resistive element coupled between said second bias terminal and said second node.