Design of voltage-mode hysteretic controllers for synchronous buck converters supplying microprocessor loads

The use of voltage-mode hysteretic control is a popular way to power modern microprocessor loads having high slew-rate current transients. A simple methodology is presented for the control design of synchronous buck hysteretic regulators based on sliding-mode control theory. The major advantage of this design approach is that the large-signal dynamic model of the hysteretic regulator can be expressed in close-loop operation as a linear system, thanks to which regular linear control techniques can be easily employed to check stability and to impose a satisfactory transient as well as steady-state performance. A detailed design example and experimental results are reported, confirming the validity of the proposed control design methodology.