Switching Power Supply Noise, Radiated EMI, and EMC
By ZM Peterson • Jan 24, 2022Learn more about switching power supply noise in this article.
Power Electronics Design
by NWES
Northwest Engineering Solutions provides power electronics design services for systems that must meet tight efficiency, EMI/EMC, thermal, and safety requirements. We design and review power conversion and control hardware spanning DC-DC power stages, gate-drive and sensing circuitry, isolation boundaries, and even mixed-signal interfaces that connect power circuitry to digital control.
Our workflow is built to take a design from early architecture through schematic, PCB layout, and a complete manufacturing package. You get actionable design outputs—component selections, layout constraints for high di/dt loops and switching nodes, creepage/clearance planning, and DFM-ready documentation—so prototypes behave like production hardware and scale cleanly to volume builds.
- Learn more about our expertise in the PCB industry.
Power Electronics Design Capabilities
Power Solutions For Advanced Designs
Modern power electronics designs push higher power density, faster switching edges (GaN/SiC), tighter EMI limits, and smaller mechanical envelopes, all while demanding higher reliability. Success comes from treating the power stage, sensing/control circuitry, and PCB layout as one coupled system, with clear constraints for switching loops, return paths, isolation barriers, and thermal spreading.
- Aggressive form factors with high power density up to ~1kW
- Board-mount power supply modules up to ~100A
- High-frequency, high-power inverters
- Designs with custom magnetics
- Multiple topologies supporting high power at standardized voltages
PCB Design Software Support
Success in Power Electronics Design
Power electronics layouts fail for predictable reasons: parasitic inductance in hot loops creates ringing and overshoot, switching nodes capacitively couple noise into control and I/O, sensing gets corrupted by return path errors, and isolation boundaries get compromised by placement or routing shortcuts. The goal is to lock down the constraints that govern switching behavior, measurement integrity, EMI performance, and safety margins before the first prototype is built.
- Topology and control strategy - Define the operating envelope first (VIN/VOUT range, load steps, protection targets, efficiency goals), then choose a topology and control method that can achieve the operating specification with sufficient margin.
- Gate drive, protection, and measurement integrity - Keep gate-drive loops tight, use Kelvin connections where appropriate, and place protection elements (desat/OC/TVS/snubbing) where they actually control the event.
- PCB stackup, copper, and grounding strategy - Select a PCB stackup that supports low-inductance planes and controlled return paths, plan copper weight/thermal spreading, and avoid reference discontinuities that turn sensitive analog/control nets into antennas.
- EMI/EMC and safety constraints - Design the filtering and grounding/chassis strategy around the connector and cable interfaces, manage common-mode paths, and enforce creepage/clearance and partitioning rules so isolation barriers and safety margins are preserved in layout.
Application Areas
We serve multiple industries and markets with advanced electronic systems operating in demanding environments.
- Motor control for industrial electronics and robotics
- Ruggedized power supplies for military and aerospace
- Space-grade power supply designs
- Modularized power supplies for embedded systems
- GaN-based and SiC-based designs
- Battery management systems (BMS)
Whether you are building a one-off prototype or preparing for volume production, we align the electrical design with your mechanical constraints and manufacturing plan. That includes component availability, PCB/material constraints, inspection requirements, and practical build notes so the design can scale without surprises.
Some power electronics design requirements in contemporary application areas are outlined in the table below.
| Application Area | Typical Design Priorities |
|---|---|
| Motor Drives and Inverters | • Stable control across load transients and operating conditions • dv/dt management to protect insulation and reduce EMI • Current measurement integrity for control and protection • Thermal design for power devices, magnetics, and mechanical mounting |
| Industrial Power Supplies and Converters | • High efficiency across the full load range • Predictable EMI/EMC performance at the system boundary • Isolation strategy with appropriate creepage/clearance margins • DFM/DFA alignment for repeatable builds and testability |
| Battery Systems (Chargers, Power-Path, BMS) | • Accurate sensing and stable references in a noisy environment • Protection coordination for fault handling and safe shutdown • Low standby power and robust sequencing/monitoring • Connector and harness considerations for conducted/common-mode noise |
| Automotive and Transportation Power | • Wide input range and transient immunity • EMI robustness with long cables and shared grounds • Thermal cycling and reliability in harsh environments • Design constraints driven by packaging and serviceability |
| Aerospace and Defense Power Conditioning | • High reliability and derating-driven design margins • Isolation and safety practices aligned to program needs • EMI control with sensitive RF/avionics subsystems nearby • Documentation and traceability expectations for builds |
| Test and Measurement Power Platforms | • Low-noise rails for precision analog and mixed-signal loads • Fast transient response without measurement corruption • Layout practices that keep noise predictable and repeatable • Serviceability and clear test access for validation |
Related Resources
Defining Power Supply Ground: System, Chassis, and Earth in Your PCB
By ZM Peterson • May 7, 2021A power supply ground region needs to be clearly defined, both on and off your PCB.
GaN vs. GaAs for RF Amplifiers and Power Conversion
By ZM Peterson • Feb 13, 2020GaN vs. GaAs: which type of amplifier is right for your application? Here’s what you need to know about these semiconductors.
Our Power Electronics Design Process
PCB for ownwer electronics can be challenging, but we're here to help guide you to success.- Contact us for a consultation and quote.
- Schematic capture begins with a focus on interface design to support analog and digital signals without interference.
- PCB layouts for power electronics require a PCB stackup that can support segmentation between analog and digital elements. We'll qualify your stackup with fabrication and finalize material requirements.
- Floorplanning, placement, and routing are completed with a focus low-noise operation and preventing crosstalk between digital and analog board sections.
- All power electronics designs go through a final DFM/DFA check, stackup review, and routing review before generating your complete PCB manufacturing data package.
Why Work With NWES?
- Broad expertise - We're a digitally-driven remote-first organization with diverse talent and experience. We know your technology because we've used it and built it.
- Manufacturing partners - We work with local and overseas CMs and EMS providers that are ISO-9001, AS9100, ISO-13485, IPC-A-610, NADCAP, and/or ITAR/JCP certified. We help you find the best option to produce prototypes and scale to volume production.
- Supply chain management - We take a proactive approach on projects to ensure your design can be produced at the required volume. We'll manage procurement from major distributors or brokers throughout your project.
Need a hand with a current or future PCB design project? Find out the difference our experts can make.
Contact us today for more information.
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