The circuit of a power source for charging a capacitive storage is described. It is based on the formation of a stepwise-decreasing current via switching of identical rectifying modules from the parallel connection to the series connection, as the storage is being charged. The comparative simulation results and experimental data are presented for the system with four output channels, which form one-, two-, or threestep current of the capacitive storage depending on the control algorithm. It is shown that the charging-cycle duration shortens with the current remaining at a constant level in most of the circuit elements.