The present application relates to electronics and in particular to switch drive circuits and more particularly to galvanically isolated switch circuits with power transfer from the switch driver input side to the switch side. More specifically, the present application provides a switch drive circuit using a single transformer to transfer control signals to a secondary side for control of the switch along with power to a secondary side circuit to drive the switch in response to the control signals. By detecting the control signal first before drawing current, the effects of leakage inductance in the transformer are reduced.