Class A+ Amplifier with Controlled Positive Feedback for Discrete-Time Signal Processing Circuits

Abstract — This paper demonstrates Class-A+ amplifier as an alternative to Class-A amplifier for discrete-time signal processing circuits. Class-A+ amplifier uses cross-coupled latches during the amplification phase at the output to improve settling accuracy compared to Class-A amplifier. The positive feedback latch is reset to fixed bias voltages of the Class-A output stage during the reset-phase. This dynamic compensation technique for realizing stable amplifier enables power and area savings with improved settling accuracy and THD performance. Simulation results show 30 % reduction in overall power consumption, 50 % reduction in the size of output stage and 10 dB improvement in settling accuracy compared to conventional Class-A amplifier with similar worst case settling time. I