CMOS variable gain amplifier and control method therefor

• Main Authors: OH CHANG JUN, SONG WON CHUL, JUNG HEE BUM
• Format: Patent
• Language: English
• Published: 10.07.2001
• Edition: 7
• Subjects: AMPLIFIERS; BASIC ELECTRONIC CIRCUITRY; CONTROL OF AMPLIFICATION; ELECTRICITY

A CMOS high frequency variable gain amplifier with maximum high frequency operation and wide variable gain characteristics that is formed from an amplifier having a plurality of variable gain amplifier cells connected in series for continuously enabling wide gain variation; and a control voltage generator for generating and outputting the control voltage of the variable gain amplifier cells. By using both the saturation region and the linear region of input differential transistors constituting the variable gain amplifier cells in order to obtain wide gain variation characteristics, it is possible for the variable gain amplifier to operate in the saturation region when the input signal is small to obtain a high gain and to operate in the linear region when the input signal is large to obtain minimum distortion and a low gain. Also, it is possible for the gain to have the characteristics in the form of an exponential function to the gain control voltage.