Patent ID: 7977990
Filing Date: 2011-07-12
Classification: H03K

Abstract:
1. A duty correction circuit comprising: a level shifter configured to receive complementary differential input signals having a duty ratio and controls levels of the differential input signals; a rise time fall time (TrTf) control circuit configured to receive output signals of the level shifter and controls edge angles of the output signals; a waveform shaping circuit configured to receive output signals of the TrTf control circuit and shapes waveforms of the output signals; a first common mode comparator configured to extract common modes of the output signals of the TrTf control circuit and compares the common modes with each other; and a second common mode comparator configured to extract common modes of output signals of the waveform shaping circuit and compares the common modes with each other, wherein the level shifter controls the levels based on outputs of the first common mode comparator, and wherein the TrTf control circuit controls the edge angles based on outputs of the second common mode comparator.