A level shifter comprising: first and second load transistors (34,36), each of the first and second load transistors having a first current electrode coupled to receive a first power supply voltage, and each of the first and second load transistors having a second current electrode, wherein an output signal of the level shifter is provided at the second current electrode of the second load transistor; first and second coupling transistors (40,42), each of the first and second coupling transistors having a first current electrode, the first current electrode of the first coupling transistor coupled to the second current electrode of the first load transistor, and the first current electrode of the second coupling transistor coupled to the second current electrode of the second load transistor, the first and second coupling transistors each having a control electrode coupled to receive a variable bias voltage; and first and second input transistors (44,46), each of the first and second input transistors having a first current electrode, the first current electrode of the first input transistor coupled to the second current electrode of the first coupling transistor, the first current electrode of the second input transistor coupled to the second current electrode of the second coupling transistor, and a control electrode of each of the first and second input transistors coupled to receive one of first and second differential input signals provided at a second power supply voltage, the second power supply voltage being lower than the first power supply voltage; and a bias voltage generator for providing the variable bias voltage, a voltage level of the variable bias voltage determined by a measured duty cycle of the output signal. first and second load transistors (34,36), each of the first and second load transistors having a first current electrode coupled to receive a first power supply voltage, and each of the first and second load transistors having a second current electrode, wherein an output signal of the level shifter is provided at the second current electrode of the second load transistor; first and second coupling transistors (40,42), each of the first and second coupling transistors having a first current electrode, the first current electrode of the first coupling transistor coupled to the second current electrode of the first load transistor, and the first current electrode of the second coupling transistor coupled to the second current electrode of the second load transistor, the first and second coupling transistors each having a control electrode coupled to receive a variable bias voltage; and first and second input transistors (44,46), each of the first and second input transistors having a first current electrode, the first current electrode of the first input transistor coupled to the second current electrode of the first coupling transistor, the first current electrode of the second input transistor coupled to the second current electrode of the second coupling transistor, and a control electrode of each of the first and second input transistors coupled to receive one of first and second differential input signals provided at a second power supply voltage, the second power supply voltage being lower than the first power supply voltage; and a bias voltage generator for providing the variable bias voltage, a voltage level of the variable bias voltage determined by a measured duty cycle of the output signal.