Low power, variable logic threshold voltage, logic gates

An integrated circuit comprising a logic gate and a master gate, the logic gate comprising:

• at least one transistor of a first conductivity type and at least one transistor of a second conductivity type in combination with additional first and second conductivity type transistors to provide a desired logic function;
• a transistor of the first conductivity type, responsive to a control signal, with outputs in series with the at least one transistor of the first type;
• a transistor of the second conductivity type, responsive to the control signal, with outputs in series with the at least one transistor of the second conductivity type;
• and
• a transistor, responsive to the control signal, in series with one of the additional first or second conductivity type transistors and of the same conductivity type;
• wherein the logic gate has a logic threshold voltage that varies in response to the control signal;
• a master gate, generating the control signal at an output, comprising:
• first, second, third and fourth transistors, each having an input terminal and two outputs, the outputs being serially connected between a first power supply rail and a second power supply rail, the connection between a middle two of the transistors being the output;
• wherein the master gate includes additional first and second conductivity type transistors to implement the same logic function as the logic gate, the input terminal of the second and third transistors being connected together and coupled to the output, the input terminal of the first and fourth transistors being connected together, the first and second transistors are of the first conductivity type and the third and fourth transistors are of the second conductivity type, and wherein the logic threshold voltage of the logic gate is substantially equal to a voltage applied to the input terminals of the first and fourth terminals of the master gate.