ANALOG SIGNAL SWITCHING CIRCUIT

摘要

PURPOSE:To reduce the switching settling time of the 1st switch group remarkably by providing the 2nd switch opened only at the switching of a channel of the 1st switch group and holding an analog signal by a capacitor while the 2nd switch is opened. CONSTITUTION:A switch 2 is opened when the contact of a switch is changed over from the S1 into the S2. Then, a voltage Es1 is stored in a holding capacitor 5. Since the voltage Es1 is changed into a comparatively smaller level difference, from Es1 into Es2 in the process of the change in an output voltage E0' of the switch 2 when the switch 2 is closed again, the level change is such a small value that the delay due to the time constant comprising the floating capacitance and a conductor resistance does not give any problem. Thus, the setting of the voltage E0' at the changeover of the switch 1 is attained at high speed. The same operation is repeated afterward until an analog signal of the n-th channel is switched. This output voltage E0' is converted in terms of impedance by a buffer amplifier 6 and a final analog output with low impedance is obtained.