In a general aspect, a circuit for controlling operation of an ignition circuit including an insulated-gate bipolar transistor (IGBT) device can include a current slope detection circuit configured to detect a slope of a current in a primary winding of an ignition coil included in the ignition circuit and a driver circuit coupled with the current slope detection circuit. The current slope detection circuit can be further configured to, during charging of the ignition coil, if the detected slope is above a first limit, provide a first indication to the driver circuit; and, if the detected slope is below a second limit, provide a second indication to the driver circuit. The driver circuit can be configured to, in response to receiving the first indication or the second indication, modify operation of the ignition circuit.