Reducing the measurement error of the time of the return recovery of rapidly recovering diodes using oscilloscopes with a narrow bandwidth

Abstract: The effect of an oscilloscope on the fronts of a current pulse of a reverse recovery of a rapidly recovering diode is considered. It is established that at different durations of the reverse voltage front and oscilloscope bandwidth, at the leading edge of the family of reverse diode recovery current curves, there is an intersection point that is numerically equal to the sum of the forward current and maximum recovery current (short circuit current). Using an oscilloscope model, its effect on the second reference point of the reverse recovery time, located on the exponential part of the current pulse, is estimated. The proposed method for correcting the exponential part of the current pulse of the reverse recovery of a fast recovery diode, together with the choice of the first reference point, allows to reduce the measurement error of the reverse recovery time when using oscillographs with a narrow bandwidth. The reverse recovery time of the diode, obtained on an Rigol DS6064 and Agilent DSO9254A oscilloscopes, diverges by 1,7%, which is 4 times less than the standard method.

Keywords: semiconductor diode, reverse diode current, reverse recovery time measurement, oscilloscope transient response, measuring path