Instabilities in Digitally Controlled Voltage-Mode Synchronous Buck Converter

In this paper, instabilities and bifurcation behavior in a DC–DC digitally controlled voltage-mode synchronous buck converter (SBC) are studied. The bifurcation diagram of the system under a proportional-integral (PI) compensation is presented. Following the system mathematical description in the continuous time domain, the z-domain pulse transfer function is derived in terms of system parameters. The stability range of the design parameter is obtained in closed form by using the Jury test combined with the describing function (DF) method. Experimental measurements from a laboratory prototype are used to validate the theoretical predictions and the numerical simulations.