Patent ID: 6674327
Filing Date: 2004-01-06
Classification: H03M

Abstract:
A multiplexer and switched gain circuit for multiplexing differential analog signals from a first channel and a second channel, both of the first channel and the second channel differential analog signals include a first part and a second part, said circuit comprising:an output line; a current source for providing a source of current, a first conduction path coupling the current source and the output line, said first conduction path including a plurality of switching devices and at least one gain device, wherein the first part of the first channel differential signal is coupled to a first switching device in the first conduction path and the second part of the first channel differential signal is coupled to a second switching device in the first conduction path, and wherein a first control line is coupled to at least one other switching device in the first conduction path, said first control line providing a control signal to turn on the first conduction path to transfer the first channel differential signal to the output line with a gain provided by the at least one gain device in the first conduction path; and a second conduction path coupling the current source and the output line, said second conduction path including a plurality of switching devices and at least one gain device, wherein the first part of the second channel differential signal is coupled to a third switching device in the second conduction path and the second part of the second channel differential signal is coupled to a fourth switching device in the second conduction path, and wherein a second control line is coupled to at least one other switching device in the second conduction path, said second control line providing a control signal to turn on the second conduction path to transfer the second channel differential signal to the output line with a gain provided by the at least one gain device in the second conduction path.