Fast response DC/DC converter with transient suppression circuit

This paper presents a novel scheme to improve the transient response of a DC/DC converter. Traditionally, a large output capacitor is used in the output of a DC/DC converter to improve transient response. However, it is costly, heavy and bulky. In this paper, the transient response of DC/DC converter can be improved by adding a coupled inductor and an auxiliary inductor. The proposed circuit configuration is very simple and the capacity of the capacitor can be minimized. A coupled inductor of the converter output filter inductor and a diode form an automatic energy feedback path to improve the full-to-low load transient response. An additional inductor is used to improve the low-to-full load transient response. The operating principle and the design criterion are addressed. Finally, an experimental prototype converter with 12V input voltage and 5V/3A output is given to verify the feasibility of the proposed scheme. Experimental results show that the low-to-full load transient response can be improved by 15% and the full-to-low load transient response is improved by 45%.