Patent ID: 7795919
Filing Date: 2010-09-14
Classification: G06F,Y02D

Abstract:
1. A driver circuit of a serial communications system for converting an input data signal into a differential signal, comprising: a first pullup resistance circuit connected to a power source voltage and configured to vary a resistance value thereof in accordance with a first input data signal; a second pullup resistance circuit connected to a power source voltage and configured to vary a resistance value thereof in accordance with a second input data signal; a third pullup resistance circuit connected to a power source voltage and configured to vary a resistance value thereof in accordance with a first control signal; a fourth pullup resistance circuit connected to a power source voltage and configured to vary a resistance value thereof in accordance with a second control signal; a first pulldown resistance circuit connected to a ground voltage and configured to vary a resistance value thereof in accordance with the first input data signal; a second pulldown resistance circuit connected to a ground voltage and configured to vary a resistance value thereof in accordance with the second input data signal; a third pulldown resistance circuit connected to a ground voltage and configured to vary a resistance value thereof in accordance with the first control signal; a fourth pulldown resistance circuit connected to a ground voltage and configured to vary a resistance value thereof in accordance with the second control signal; a first output terminal connected to a first transmission line, the first pullup resistance circuit, the first pulldown resistance circuit, the third pullup resistance circuit, and the third pulldown resistance circuit; and a second output terminal connected to a second transmission line, the second pullup resistance circuit, the second pulldown resistance circuit, the fourth pullup resistance circuit, and the fourth pulldown resistance circuit, wherein the first and second transmission lines transmit the differential signal, wherein the first control signal is independent of the first and second input data signals, and wherein the second control signal is independent of the first and second input data signals.