May 11, 2017
High-frequency conducted and radiated emissions from power converters occur based on the transient voltage (dv/dt) and transient current (di/dt) generated during hard switching. Such electromagnetic interference (EMI) is an increasingly complex issue in the design and qualification cycle, especially given the increased switching speed of power MOSFETs.
1.EMI overview and fundamentals
–EMI noise coupling paths (DM & CM)
–EMI standards: EN55022 class B (industrial, comms), CISPR 25 class 5 (automotive)
–EMI measurement setup & LISN schematic
–EMI filtering, DM & CM equivalent circuits, CM noise propagation paths
2.EMI noise sources and mitigation
–“Hot” loops, parasitic inductance, magnetic fields
–SW node harmonics & voltage ringing, electric fields
–Circuit and layout techniques for EMI mitigation
3.EMI management in DC/DC converters
–Component placement, GND plane management, PCB stack-up strategies, etc.
–Practical circuit examples, EMI performance-optimized PCB layouts, EMI results
LM5145: VIN = 6V to 100V, VOUT = 5V, IOUT = 20A [PCB layout, input caps, inductor selection]
LM53635-Q1: VIN = 3.5V to 42V, VOUT = 5V, IOUT = 3.5A [HotRod package, SSFM, PCB layout]
Date: June 20, 2017
2Reducing EMI through IC and package innovations (7)
Reducing EMI starts with device selection. Learn about various silicon and packaging technologies that can help you mitigate EMI from the start.
3Reducing EMI through input filter design, PCB and BOM optimization (5)
If your device has switching elements, it's going to emit EMI. Learn how to minimize it through input filter design, PCB and BOM optimization.
4Application-specific EMI considerations (5)
Certain applications require unique EMI considerations. Let's take a look at a few examples in this section.