A circuit for use in a half bridge converter includes a high side switch coupled between a positive input terminal and a first terminal of a primary transformer winding. A low side switch is coupled between a negative input terminal and the first terminal. A first control circuit is coupled to the high side switch to sense a slope of a voltage across the high side switch while the high side switch is off to control the high side switch in response to the sensed slope across the high side switch. A second control circuit is coupled to the low side switch to sense a slope of a voltage across the low side switch while the low side switch is off to control the low side switch in response to the sensed slope of the voltage across the low side switch.