Title :
CMOS combined feedforward/feedback AGC circuit for VHF applications
Author :
Alegre, J.P. ; Calvo, B. ; Celma, S. ; Aznar, F.
Author_Institution :
Electron. Design Group (I3A), Univ. of Zaragoza, Zaragoza, Spain
Abstract :
This paper presents an automatic gain control (AGC) circuit targeting 250 MHz IF applications based on a combined control loop: a fast settling feedforward loop performs coarse gain adjustment, while a conventional feedback loop realizes final fine gain tuning. The AGC consists of a low-voltage broadband CMOS programmable gain amplifier and the loops are implemented making use of novel peak detection methods and other simple circuitry. The complete AGC has been designed in a standard 0.35 μm CMOS technology with 1.8 V supply voltage and exhibits a total current consumption below 1.22 mA. Measurements offer a settling-time below 0.8 μs and a 12 dB gain adjustment with an error <;±1 dB.
Keywords :
CMOS integrated circuits; VHF circuits; amplifiers; automatic gain control; feedback; feedforward; low-power electronics; CMOS combined feedforward/feedback AGC circuit; CMOS technology; VHF applications; automatic gain control; control loop; current 1.22 mA; feedback loop; feedforward loop; frequency 250 MHz; low-voltage broadband CMOS programmable gain amplifier; peak detection methods; size 0.35 mum; voltage 1.8 V; Automatic control; Broadband amplifiers; CMOS technology; Circuit optimization; Feedback circuits; Feedback loop; Gain control; Performance gain; VHF circuits; Voltage;
Conference_Titel :
Circuits and Systems (MWSCAS), 2010 53rd IEEE International Midwest Symposium on
Conference_Location :
Seattle, WA
Print_ISBN :
978-1-4244-7771-5
DOI :
10.1109/MWSCAS.2010.5548721
