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DEW Home›Electrical & Electronics›Power Supplies
Electrical & Electronics · Category Intelligence

Power Supplies

Units that convert AC mains (or a DC bus) into the clean, regulated DC that equipment runs on. The pick is driven by output power and voltage, isolation/safety class (industrial vs medical), efficiency and heat, form factor, and how much redundancy the load demands.

◆ Deep category · engineer-grade decision intelligence

Product types

Where engineers draw the lines within power supplies.

AC-DC — Enclosed / Configurable
Mains to regulated DC in an enclosed or configurable (multi-output) package. The industrial workhorse — from board-level to multi-kW rack systems.
AC-DC — Medical (MOPP)
Reinforced isolation and low leakage certified to IEC 60601-1 with 2×MOPP for patient-contact equipment.
DC-DC Converter (isolated / PoL)
Regulates a DC bus to one or more rails — isolated bricks or non-isolated point-of-load for distributed power architectures.
Programmable DC (bench / rack)
Remote-controlled DC source (LAN/LXI, USB, GPIB, analog) for test, burn-in, and process power — kW-class rack units scale to high power.
DIN-Rail
Panel AC-DC for control cabinets, with redundancy/ORing modules and wide-temperature ratings.
EMC/EMI Filter
Line filters that suppress conducted noise so the equipment passes EMC — single- and three-phase, chassis and block types.

Specs that matter

The numbers to compare first — and which are hard deal-breakers.

Output power & voltage / current
The first cut — must cover the load plus startup surge and headroom. Low-power board supplies and multi-kW systems are different product families.
Deal-breaker
Isolation & safety class (IEC 62368-1 / 60601-1)
Industrial (basic/reinforced) vs medical (2×MOPP, low leakage) is a hard gate set by the end product.
Deal-breaker
Efficiency & thermal derating curve
Drives heat, enclosure, and whether the unit holds full output at your ambient — headline efficiency hides the derating.
Deal-breaker
Form factor & cooling (convection vs fan)
Must fit the space and cooling scheme; fanless for sealed/quiet, forced-air for high density.
Key
Hold-up time
Ride-through of mains dropouts — critical for controllers and safe shutdown.
Key
Redundancy / ORing / parallel
N+1 and current-share for uptime-critical loads.
Key
Regulatory & EMC (EN 55032 class B, DoE VI)
Conducted/radiated emissions and no-load/efficiency mandates the product must meet.
Key
Environmental (temp range, conformal, altitude)
Derating, coating, and altitude affect life and output in the real installation.
Nice-to-know
Interfaces (PMBus, remote on/off, monitoring)
Digital monitoring and control for programmable and system power.
Nice-to-know

How engineers decide

Rules of thumb behind the common trade-offs.

Linear or switching?
Switching for essentially all industrial power — far higher efficiency and power density. Linear only for the lowest-noise analog rails where its clean output justifies the size and heat.
Industrial or medical supply?
If the equipment touches a patient or is a medical device, you need a 60601-1 supply with the right MOPP (means of patient protection) and leakage limits — an industrial 62368-1 unit won't certify. Buy medical from the start; retrofitting isolation is expensive.
How much power headroom?
Size for the peak (including inrush and startup surge), then derate for ambient temperature and altitude. A supply rated at 25°C may deliver noticeably less at 50°C — read the derating curve, don't trust the headline watts.
When do I need redundancy?
For loads where downtime is unacceptable, use N+1 with ORing modules so a failed unit or feed doesn't drop the bus. Confirm true current-sharing, not just paralleling.
Programmable or fixed?
Programmable rack/bench supplies for test, burn-in, and processes needing set-and-read control over LAN/GPIB. Fixed enclosed/DIN supplies for embedded, always-on rails at lower cost.
▼ From the field

What goes wrong — War Stories

Expensive failure modes engineers design around.

⚠ Thermal foldback / output sag at ambient
Cause: Sizing to headline (25°C) watts, ignoring the derating curve
Design around it: Read the temperature-derating curve, add margin, improve airflow, or step up a size for hot enclosures.
⚠ Inrush trips upstream breakers
Cause: High cold-start inrush current, several supplies on one feed
Design around it: Check inrush spec, use units with inrush limiting, sequence/stagger turn-on, size breakers with inrush in mind.
⚠ No ride-through on mains dips
Cause: Insufficient hold-up time for the controller/PLC
Design around it: Spec adequate hold-up (or a buffer/UPS module) so control survives brownouts and drops.
⚠ EMC failure at test
Cause: Inadequate input filtering, poor grounding/layout
Design around it: Add/spec the right EMC filter (RSHN/RSEN class), tighten grounding and cable layout, verify against EN 55032 early.

Key builders

Manufacturer-direct sources we anchor specs to.

TDK-Lambda — Low-Power division (CUS/CUS-M enclosed, i6A non-isolated PoL, PXC isolated DC-DC)TDK-Lambda — High-Power division (HWS-G / TPS multi-kW AC-DC, GENESYS+ & Z+ programmable rack)Mean WellVicorAdvanced Energy (Artesyn)Delta ElectronicsCoselXP PowerTRACO PowerRECOMBel Power SolutionsMurata Power Solutions

Standards we hold specs to

IEC/UL 62368-1Safety for ITE / AV / industrial electronic equipment
IEC 60601-1 (2×MOPP)Medical electrical equipment — patient protection & leakage
EN 55032 / IEC 61204-3EMC — conducted & radiated emissions for power supplies
DoE Level VI / 80 PLUSExternal-supply & efficiency / no-load mandates
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