Patent ID: 7068194
Filing Date: 2006-06-27
Classification: H03M

Abstract:
1. An apparatus for converting a digital input signal to an output current at an output terminal, the apparatus comprising: a first transistor circuit that is arranged to operate as a first current source that is selectively enabled via a first control terminal, wherein: the first transistor circuit is comprised of a single transistor type, and a first current from the first transistor circuit is coupled to the output terminal when the first transistor circuit is enabled; a second transistor circuit that is arranged to operate as a second current source that is selectively enabled via a second control terminal, wherein: the second transistor circuit is comprised of the single transistor type, a second current from the second transistor circuit is coupled to the output terminal when the second transistor circuit is enabled, and a magnitude associated with the first current is substantially matched to a magnitude associated with the second current; a first switching circuit that is arranged to selectively couple a first input terminal to the first control terminal in response to a first control signal, wherein the first switching circuit is comprised of the single transistor type; a second switching circuit that is arranged to selectively couple a second input terminal to the first control terminal in response to a second control signal that is an inverse of the first control signal, wherein the second switching circuit is comprised of the single transistor type; and a third switching circuit that is arranged to selectively couple the first input terminal to the second input terminal in response to a third control signal, wherein: the second input terminal is coupled to the second control terminal, and the third switching circuit is comprised of the single transistor type.