Transformerless DC-DC converters with a very high DC line-to-load voltage ratio
By splitting the output capacitor of a basic boost converter, and combining the resulting capacitors with the main switch in the form of a switched-capacitor circuit, a new step-up structure is realized. Without using a transformer, a high line-to-load DC voltage ratio is obtained. An output filter is added, as usual, in boost converters for getting a free-ripple output. The circuit compares favorably with a quadratic boost converter regarding the count of devices and efficiency, even if it presents a lower DC gain. A DC analysis of the novel converter is presented. Experimental and simulation results confirm the theoretical expectations. By increasing the number of capacitors in the switched-capacitor circuit, higher gains can be obtained. Versatility, high voltage gain and good transient response are the features of the proposed converter.
dc-dc converter switched capacitor high voltage ratio