A model of a two-output voltage step-up/current step-up dc-to-dc converter is presented which demonstrates how the leakage flux associated with the energy-storage transformer affects cross regulation. First, expressions are derived which show the strong influence that leakage flux has on the secondary current waveforms. Then, after imposing steady-state constraints on the two equations describing the secondary current waveshapes, the cross regulation performance of the converter can be predicted. A comparison of predicted and observed results suggests that this model can be a useful tool for understanding converter cross regulation performance as well as for guiding the design of the energy-storage transformer in a multiple-output converter.