PURPOSE: To obtain small resistance with a small circuit element, by doubling a capacity constituting a switched capacitor apparently to reduce the capacity value on an IC chip.
CONSTITUTION: Connections of contacts of switches 3 and 5 are controlled by a clock signal so that they are operated in phases opposite to each other. When the contact of the switch 3 is connected to a terminal 1, the contact of the switch 5 is connected to the earth, and therefore, charge is charged to a capacity 4 in an instant, and the voltage between terminals of the capacity 4 becomes a voltage V1 of the terminal 1. Next, when the contact of the switch 3 is connected to a terminal 2, the contact of the switch 5 is connected to the terminal 1, and the voltage V1 of the terminal 1 is superposed to the voltage of the capacity 4. That is, the voltage between terminals of the capacity 4 has variation V21 by switching of switches 3 and 5.
ITOIGAWA KEIICHI
KUWABARA KAZUMI
HITACHI MICROCUMPUTER ENG