A novel circuit for accurate characterization and modeling of the reverse recovery of high-power high-speed rectifiers

Abstract

As circuit switching frequency continues to increase, there is a need to produce faster rectifiers with lower power losses. Efficient utilization of high-power ultrafast rectifiers requires precise knowledge of the key static and dynamic switching parameters, especially the reverse-recovery characteristics. Conventional reverse-recovery test circuits were developed to test rectifiers with reverse-recovery times (t/sub RR/) greater than 100 ns, however, new measurement techniques are needed for accurate characterization and modeling of the high-power ultrafast rectifier reverse-recovery process. A test circuit topology is proposed which offers several advantages over existing test circuits. This circuit offers the ability to characterize high-power ultrafast rectifiers at very high di/dt and also provides independent control of bias current, reverse voltage and di/dt. This circuit is also studied using a two-dimensional (2-D) mixed device and circuit simulator in which the device under test is represented as a 2-D finite-element grid and the semiconductor equations are solved under boundary conditions imposed by the proposed test circuit. This simulation tool is used to understand the device physics of the reverse-recovery process and develop more accurate models to be implemented in behavioral circuit simulators. The simulation results are then compared to the measured data for a silicon P-i-N and 200-V GaAs Schottky rectifier under various measurement conditions. Simulation results are shown to be in excellent agreement with the measured data.