Evaluating Requalification and Layout Expenses in Wide Bandgap Power Conversions
Evaluating wide bandgap power conversions requires balancing switch price premiums and board redesign costs against magnetic component and enclosure savings.
Power Loop Inductance
Meaning
Total parasitical inductance within the high-current switching path of a power electronic converter governs the magnitude of voltage spikes during turn-off events. Designers must minimize power loop inductance to prevent semiconductor damage from high transient voltages. A tight and optimized layout is essential to achieve fast switching speeds and high efficiency.
Electromagnetic Effect
High switching frequencies generate severe voltage overshoots when power loop inductance is allowed to remain high. This transient stress can breach the dielectric rating of the transistor and cause immediate failure. Minimizing this parameter requires co-designing the PCB layout with the module package.
Component Selection
Choosing the right packaging style is an important factor in reducing power loop inductance. Modern semiconductor modules integrate bypass capacitors directly onto the substrate to shorten the current path. Selecting these advanced modules helps engineers meet their performance goals without extensive custom filters.
Purchasing Specification
Industrial buyers include maximum allowable limits for power loop inductance in the technical specifications attached to supply agreements. If the component fails to meet these inductance limits during qualification testing, the shipment can be rejected. This requirement protects the buyer from receiving sub-standard hardware that could jeopardize the reliability of the end product and increase the cost of warranty service.
Clear limits ensure that both parties have a shared standard for quality control.