Multiplexer with Level Shifter

A method comprising:

• a multiplexer selecting a first signal received from a first functional unit operating in a first voltage domain;
• level shifting and outputting the first signal to a second functional unit operating in a second voltage domain;
• selecting, using the multiplexer, a second signal received from a third functional unit operating in the second voltage domain;
• and
• outputting the second signal to the second functional unit.

A circuit comprising:

• a level shifter configured to receive a first input signal from a first voltage domain to provide an output signal in a second voltage domain;
• a first transistor coupled to an output of the level shifter and configured to pull the output node up in response to a second input signal in the second voltage domain, wherein the output of the level shifter is in the second voltage domain;
• and
• a second transistor coupled to the output and configured to pull the node down in response to a second input signal;
• wherein the first transistor, the second transistor, and the level shifter are further controlled response to a select signal that selects between the first input signal and the second input signal.

An integrated circuit comprising:

• a first functional unit configured to operate at a first voltage;
• a second functional unit configured to operate at a second voltage;
• and
• a multiplexer coupled to receive a first signal from the first functional unit and a second signal from the second functional unit, wherein the multiplexer is configured to:
• select the first input signal responsive to receiving a selection signal in a first state;
• select the second input signal responsive to receiving the selection signal in a second state;
• and
• output the selected one of the first or second signals to a third functional unit operating at the second voltage, wherein the multiplexer is configured to level shift the first input signal responsive receiving the selection signal in the first state.