Statistical Analysis of the Serial Connected Diode Chain Under Reverse Bias Devices

摘要

This article deals with the reverse voltage distribution along a chain of large number serial connected power silicon diodes. Reverse properties of an individual diode can be affected by random influences of its production process. The consequence of this fact implies an inequality distribution of reverse bias inside the diode chain. This is the cause of so called High Voltage Diode Stack (HVDS). Each HVDS consists of 50-100 diode chips and its total reverse voltage usually exceeds 100 kV. While reverse current - voltage characteristics can be measured in detail for each diode chip, no direct measurement of the voltage distribution is possible during operation HVDS, with respect to the its compact construction. That is why a physical model was created for the course of reverse current - voltage HVDS' characteristics and sufficiently precise estimations were made by means of suitable statistical methods as to the individual voltage distribution. This model is also generalized for case of avalanche multiplication. Important conditions of the device reliable operation are defined and the courses of real and computed characteristics are compared. It is shown that the credible prediction can be made as to the reverse characteristics shapes model at low and high applied voltages.