Patent ID: 7737755

Claim:
A level shifter, comprising: an input circuit comprising a signal input configured to receive an input signal, and a first voltage input coupled with a first supply voltage; an output circuit comprising a signal output configured to output an output signal, and a second voltage input coupled with a second supply voltage different from said first supply voltage; and at least one switch coupled between said input circuit and said output circuit and controlled by said first supply voltage such that said at least one switch is configured to (a) couple said input circuit with said output circuit responsive to said first supply voltage being applied to said at least one switch and to (b) decouple said input circuit from said output circuit responsive to said first supply voltage not being applied to said at least one switch, wherein said level shifter is configured to generate said output signal based on said input signal through level shifting when said at least one switch establishes a connection from said input circuit to said output circuit, wherein said output circuit is configured such that said signal output assumes a predetermined state responsive to said input circuit being decoupled from said output circuit by said at least one switch, wherein said output circuit comprises a first transistor and a second transistor, a first load terminal of said first transistor and a first load terminal of said second transistor are coupled with said second voltage input, a second load terminal of said first transistor and a control terminal of said second transistor are coupled with a first circuit node, a second load terminal of said second transistor and a control terminal of said first transistor are coupled with a second circuit node, and at least one circuit node chosen from the group consisting of said first circuit node and said second circuit node is coupled with a switch of said at least one switch, and wherein said level shifter further comprises a discharge path coupled with said first circuit node and a control circuit configured to activate said discharge path based on a state of said first voltage input and a state of said signal output.