This disclosure is directed to circuits and techniques for detecting or responding to temperature of a power switch. A driver circuit for the power switch may be configured to deliver a modulation signal to a control node of the power switch to control on/off switching of the power switch, wherein the driver circuit is further configured to modulate an output impedance of the driver circuit at the control node, perform one or more voltage measurements while modulating the output impedance of the driver circuit, and control the power switch based at least in part on the one or more voltage measurements.