Recent work has shown the use of shim and gradient coil arrays for dynamic shimming and novel spatial encoding methods. These arrays require precise current source drivers with high power and bandwidth. Because of these demands, shim and gradient arrays are typically driven with amplifiers which are located outside the magnet bore due to constraints on power dissipation, radiofrequency interference (RFI), or magnetic materials. Here we present a highly efficient digitally-controlled switchmode current driver. We demonstrate that it is feasible to shield the RFI from the receive chain while avoiding ferrous materials and large heatsinks.