SDG #278 Assembling and Testing the High Current MOSFET driver

This episode moves the high current MOSFET driver project from schematic to working hardware. The freshly delivered boards are inspected first, with attention paid to the copper pour, gate trace routing and pad geometry, all of which matter more than usual on a board expected to slam large gate charges around at speed. Assembly is then walked through component by component, which is useful viewing if you are building something similar and want to see the practical order of operations for mixed passive and power parts.

The interesting part is the validation. First power-up is treated cautiously, checking that the driver behaves sensibly before anything is loaded. From there the board goes on a Picoscope 5000 series so the gate waveforms can be examined properly: rise and fall times, edge quality, overshoot and ringing, and whether the driver is actually delivering the peak current the design promised. This is the sort of measurement that separates a driver that works on paper from one that will actually switch a large MOSFET cleanly without cooking it in the linear region.

A thermal camera pass follows, which is a quick and effective way to spot components dissipating more than expected, marginal current paths or a driver IC working harder than intended. Thermal imaging on a freshly built board frequently reveals problems that a scope trace will not.

The closing section looks at where the design goes next, including the limits found during testing and the changes worth making on a revision. Worth watching if you are designing gate drive circuitry and want a realistic view of how much measurement is needed before trusting a board.