Fast transient response with combined linear-non-linear control applied to buck converters

Nowadays, one of the main challenges for power supplies designers is to feed the latest generation of microprocessors and DSPs, since they require high current slew rates together with low output voltage. In this paper, a novel control technique is presented to help the designers to comply with the current requirements. The proposed combined linear-nonlinear control (LnLC) scheme increases significantly the capability of conventional linear control to reduce the recovery time of the output voltage drop produced when a load current step occurs. Experimental results have been obtained for two cases: a synchronous rectifier buck converter, with a conventional voltage loop and the same converter with the novel LnLC. The comparison of these experimental results shows that, with the new control, the recovery time of the output voltage is reduced.