AUTOMATIC CORRECTING CIRCUIT OF ERROR IN MULTIPLEXER

摘要

PURPOSE:To eliminate an error due to a leak current of an analog switch including temperature fluctuation by inputting a reference potential to an input of an analog switch circuit together with an analog signal, storing an error voltage generated by the leak current at the selection of the reference potential and subtracting the said error voltage from the selected output signal. CONSTITUTION:An error voltage epsilonV proportional to the leak current IL existing in switches 41-4n of an analog switch circuit 3 is stored in a sample-and-hold (S/H) circuit 17 at the selection of a reference potential signal source 10. This error voltage epsilonV is superimposed on an analog signal of the said signal sources even in selecting analog signal sources 11-1n. Thus, a selected output signal of the analog signal source is inverted at an inverse amplifier 19 and subtracted from an error voltage of the sample-and-hold circuit 17, allowing to obtain the analog signal eliminating the error voltage component in an output of an adder 20.