Current-mirror based PID controller

In this paper, the architecture of the Proportional-Integration-Derivative (PID) controller, based on the current-difference amplifier, is presented. This architecture allows to integrate the controller, employing only four active MOS transistors. It also allows obtaining interesting features, such as the low power consumption, and high bandwidth, in spite of the low DC accuracy (offset). In this paper, basic design equations for the DC operation point setting, transfer function, and the MOS transistor sizing are provided. The performances are demonstrated by a simulation of the circuit designed in 40nm CMOS, employed to stabilize the feedback-loop of the switched DC/DC buck converter.