Patent ID: 6759889
Filing Date: 2004-07-06
Classification: H03K

Abstract:
A multiplexer circuit for switching a selected one of a plurality of current inputs carried by respective input lines to a common output, said circuit comprising, for each respective input line:a diode clamp including first and second clamp terminals and first and second clamp diodes arranged in series with the same polarity between said clamp terminals; and isolation means provided between each respective input line and said common output, wherein each input line is connected only to the isolation means and to a point between said first and second clamp diodes, and wherein said diode clamp is operable in two modes, a first mode in which voltages are applied to said clamp terminals such that said diodes of said diode clamp are forward biased and hold said input line at a first voltage which prevents a passage of current from said input line to said common output, and a second mode in which the voltages are applied to said clamp terminals such that said diodes of said diode clamp are reverse biased and said passage of said current from said input line to said common output is allowed, and wherein only two connections to the diode clamp control switching of the respective input line.