a bridge rectifier configured to provide a rectified alternating current (AC) voltage to a first node;

a primary side switch comprising a drain, the drain electrically coupled to the first node via a first circuit path, the first circuit path comprising a first circuit path node between the first node and the drain; and

a controller configured to control the primary side switch according to a switching waveform, the controller comprising a voltage monitor input electrically coupled to the first circuit path node via a second circuit path, the second circuit path configured to provide a monitor voltage to the voltage monitor input and comprising a second circuit path node configured to provide a node voltage according to a relationship between a first current, a second current, and a third current,

wherein the second circuit path is configured to provide the first current and the third current, and the second circuit path node is between the first circuit path node and the voltage monitor input, and

wherein the controller further comprises a control input, the control input electrically coupled to the second circuit path node via a fourth circuit path configured to provide the second current.