Adaptive Drive Signal Adjustment for Bridge EMI Control

摘要

An embodiment of the invention relates to a driver adapted to provide a drive signal with an adjustable waveform for an external bridge to control EMI. The driver includes a detector configured to measure a switching characteristic of a switch in the external bridge to produce the drive signal with an adjustable waveform characteristic. The driver includes an adjustable circuit element to adjust the waveform characteristic in response to the measured switching characteristic. The measured switching characteristic may be a derivative of a voltage of the switch in the bridge such as a derivative of a drain-to-source voltage of a half-bridge circuit. The driver may be formed with an amplifier with an adjustable gain controlled by the signal produced by the detector. The adjustable gain amplifier may be formed with a transistor coupled in series with a leg of a current mirror.