Analysis and implementation of a semi-integrated Buck converter with static feedback control

The switches and the control circuit of Buck converter with static feedback control have been implemented in a standard digital 0.6 /spl mu/m CMOS process. The control used is a direct large-signal approach, and the converter has been proven to be globally asymptotically stable using the theory of successors in combination with Lyapunov's direct method. One very important design parameter is the output ripple, and prediction has shown good agreement between the describing function method and simulations. The simulated ripple of the implemented converter is of the order of /spl plusmn/3%, and the efficiency of the complete converter is approximately 75% at 1.5 V output on a 10/spl Omega/ resistive load. The inductor and capacitor are external components, but the rest of the converter is integrated and occupies 1.9 mm/sup 2/. The start-up is very quick (/spl sime/10 /spl mu/s) and so is the recovery from any disturbance.