Advances in active-feedback frequency compensation with power optimization and transient improvement

This paper presents a low-power stability strategy to significantly reduce the power consumption of a three-stage amplifier using active-feedback frequency compensation (AFFC). The bandwidth of the amplifier can also be enhanced. Simulation results verify that the power dissipation of the AFFC amplifier is reduced by 43% and the bandwidth is improved by 32.5% by using the proposed stability strategy. In addition, a dynamic feedforward stage (DFS), which can be embedded into the AFFC amplifier to improve the transient responses without consuming extra power, is proposed. Implemented in a 0.6-μm CMOS process, experimental results show that both AFFC amplifiers with and without DFS achieve almost the same small-signal performances while the amplifier with DFS improves both the negative slew rate and negative 1% settling time by two times.