A non-isolated dc-dc converter with chain- links of sub-modules (SMs) is proposed in this paper. The converter can perform as a dc transformer with low step- up ratio. To demonstrate the step-up dc-dc conversion, the converter is operated in resonant conversion mode, achiev- ing soft-switching and inherent-balancing of SM capacitor voltages. The circuit configuration is presented and the operation principle is analyzed in the paper. Experimental results based on a downscaled prototype validate the per- formance of the proposed converter as a low step-up ratio dc transformer. The converter also exhibits a good linearity covering a broad range.