75A/250V/75KHz intelligent half bridge power module

Class D switching power amplifiers for driving electrodynamic shake tables must offer low distortion, good efficiency and reduced Radio Frequency Interference. Low distortion implies high switching frequencies, with turn on and turn off delay times as short as possible. Paralleling MOSFET chips contributes to decreased conduction losses through reduced Rdson. It Is Imperative to inhibit the MOSFET body diodes by adopting both series and fast recovery "soft" antiparallel FRED's. With such a complex structure it makes eminent sense to integrate all these components as a complete half bridge inside a single power module. In this way, interconnection parasitics are minimized. resulting in less environmental disturbance and improved reliability. Reliability is further enhanced by integrating driver power supplies undervoltage lockout, short-circuit protection and temperature monitoring all with associated fault output flags. The drivers themselves are galvanically isolated via high frequency transformers. Power Compact, in collaboration with LDS, has developed an intelligent half bridge power module satisfying all these criteria; this module, described in this paper, is featured in LDS' latest switch-mode power amplifiers.