Abstract-High switching frequencies (several MHz) allow the integration of low power DC/DC converters. Although, in theory, a high switching frequency would make possible to implement a conventional voltage mode control with very high bandwidth, in practice, parasitic effects and robustness make very complex to achieve bandwidths higher than 1MHz. This paper proposes a fast control technique to optimize the dynamic response of high switching frequency DC/DC converters. The proposed control is based on two loops. The fast internal loop has information of the output capacitor current and the error voltage, providing fast dynamic response under load and output voltage reference steps, while the slow external voltage loop provides accurate steady state regulation. Experimental results validate the fast dynamic response of the proposed control under load and output voltage reference steps and its suitability for high switching frequencies.

-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.Index Terms-DC/DC converters, high switching frequency, fast dynamic response, output capacitor current and integration.

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