A transformer driver circuit couples to a transformer having a primary winding, a secondary winding, and a transformer tap that is connected to a first voltage source. The primary winding electrically connects at its ends to respective unipolar controllable current sinks that form part of an integrated circuit. The transformer driver circuit operates by each current sink selectively sinking current from the end of the primary winding to which it is connected so as to cause current to flow in the secondary winding in a push-pull fashion. The transformer driver circuit further includes a load electrically connected to the secondary winding and protection circuitry operative to protect the integrated circuit from input levels greater than it can withstand.