VARIABLE RESISTOR WITH VARIABLE RESISTOR VALUE IN EQUAL RATIO, A VARIABLE GAIN AMPLIFIER USING THE SAME, A VARIABLE CUTOFF FREQUENCY FILTER, AND A CONTROL METHOD THEREOF

摘要

PURPOSE: A variable resistor with variable resistor value in equal ratio, a variable gain amplifier using the same, a variable cutoff frequency filter, and a control method thereof are provided to set up a variable gain by using control code.;CONSTITUTION: A first resistance segment(210) and second resistance segments(211,212,213) are serially connected. The first switches(221,222,223) are connected to the second resistance segment in parallel. The second switches(231,232,233) are serially connected to the second resistance segment. A variable resistor(200) is controlled by the control signals of 2 bit. The variable resistor is connected to the first resistance segment and the second resistance segments in parallel. The first switch changes the connection state of at least one among second resistance segments according to control signal of 2 bits. The second switch is serially connected to the second resistance segment.;COPYRIGHT KIPO 2012