Patent ID: 7551017
Filing Date: 2009-06-23
Classification: H03F

Abstract:
1. A level shifter comprising: a current generator for generating a first source current and a second source current, wherein the current generator includes a first level shift module adapted to produce a shifted signal by adjusting a direct current (DC) level of an input signal by a first bias voltage having a first polarity, wherein the first bias voltage is generated based on the first source current, and the first level shift module includes a first level shift FET having a gate coupled to receive the input signal, a source coupled to the current source, and a drain coupled to the drain of the first current mirror FET, to the gate of the first current mirror FET, and to the gate of the second current mirror FET; and a second level shift module adapted to produce an output signal by adjusting a DC level of the shifted signal by a second bias voltage having a second polarity, wherein the second level shift module includes a second level shift FET having a source coupled to the current source, a drain coupled to the drain of the second current mirror FET, and a gate coupled to the drain of the second current mirror FET, and wherein the second bias voltage is generated based on the second source current, and wherein the first polarity is opposite to the second polarity, and wherein a sum of a magnitude of the first bias voltage and a magnitude of the second bias voltage is a non-zero voltage that corresponds to a total shift in DC level between the input signal and the output signal.