Fast control technique based on peak current mode control of the output capacitor current

The control proposed and analyzed in this paper is based on the peak current mode control of the output capacitor current of a Buck converter. The output capacitor current loop provides fast dynamic response to the control since it behaves as a feed-forward of the load current while the voltage loop provides accurate steady state regulation. A simulation oriented averaged model of the proposed control has been developed to design the external voltage loop. As shown in simulations, with the converter switching at 5 MHz, the proposed control with a voltage loop of 50 kHz bandwidth has the same voltage drop and a similar dynamic response as a 1 MHz bandwidth voltage mode control. The reduction of the bandwidth makes easier the control implementation and integration. Finally, experimental results have been achieved verifying the fast dynamic response of the proposed control under load steps.