This application note describes a low cost power board design for the ST92141 motor control MCU without using IPMs.
The document discusses Intelligent Power Modules (IPMs), which integrate IGBTs, diodes, and interfacing circuits into a single package. It evaluates their benefits, such as reduced component count and assembly costs, against drawbacks like lead frame constraints, heatsink planarity requirements, and the need for external bootstrap diodes and temperature protection.
An alternative solution is proposed that separates system components onto two boards: a Control Board containing microcontrollers and peripheral circuits, and a Power Board with discrete power switches. This partitioning aims to optimize cost, improve reliability through differentiated soldering processes, and allow flexible thermal management using cheap heatsink technologies.
The major advantages include less assembly cost, lower component count, reduction in time to market, higher reliability, product compactness, and low inductance package.
Drawbacks include lead frame constraints requiring parallel PCB installation, heatsink planarity and stiffness issues, embedded gate drive filter costs, the need for external bootstrap diodes and temperature protection, and scarce component choice.
The proposal involves grouping system SMD components on a small Control Board and keeping power switches and discrete components on a separate Power Board.