Title :
An automatic offset compensation scheme with ping-pong control for CMOS operational amplifiers
Author :
Yu, Chong-Gun ; Geiger, Randall L.
Author_Institution :
Dept. of Electr. Eng. & Comput. Eng., Iowa State Univ., Ames, IA, USA
fDate :
5/1/1994 12:00:00 AM
Abstract :
An automatic offset compensation scheme for CMOS operational amplifiers is presented. Offset is reduced by digitally adjusting the bias voltage of a programmable current mirror which is used as the load of the differential input stage. A 100% operating duty cycle is obtained by using a ping-pong structure. The offset compensation scheme is inherently time and temperature stable since the offset compensation is periodically performed with the ping-pong control. The proposed circuit has been fabricated using a 1.0 μm n-well CMOS process. The measured offset voltages of the test circuits are less than 400 μV in magnitude
Keywords :
CMOS integrated circuits; differential amplifiers; digital control; error compensation; linear integrated circuits; operational amplifiers; tuning; 1 micron; 100% operating duty cycle; CMOS operational amplifiers; automatic offset compensation scheme; bias voltage; differential input stage; digital adjustment; n-well CMOS process; op amp; ping-pong control; programmable current mirror; Automatic control; CMOS process; Circuit testing; Mirrors; Operational amplifiers; Resistors; Switches; Temperature control; Variable structure systems; Voltage;
Journal_Title :
Solid-State Circuits, IEEE Journal of
