This paper reports on the first realization using high temperature superconducting films of the device proposed in 1965 by Giaever: the DC-DC transformer, which involves flux-flow vortex motion in two superimposed thin films, separated by a thin insulating layer. The device was fabricated using the ramp based multilayer technology from an YBa₂Cu₃O₇ based SIS structure grown by pulsed laser deposition. Transport measurements exhibiting the coupling and decoupling phenomena between the two vortex arrays are obtained. We discuss the possibility of widening the working range of this device, which constitutes an important result in the effort to use high temperature superconductors for electronics.