[en] In cyclotron the magnetic field shaping is provided by the main magnet and along with that a set of auxiliary coils called the trim coil. The room temperature cyclotron (K=130) at VECC, Kolkata requires seventeen number of Trim Coil Power Supply to drive the magneto-optic system for proper beam dynamics of the cyclotron. Numbers of these are continuously variable high-current dc (750 A, 12 V) power supplies. For stable beam from the cyclotron a need is felt for the prototype design of such a power supply with higher long-term current stability along with high reliability to minimize the down time of the cyclotron. (author)