• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
  • Skip to footer

Power Electronic Tips

Power Electronic News, Editorial, Video and Resources

  • Products
    • Power Supplies
    • AC-DC
    • DC-DC
    • MOSFETS
    • Power Management
    • Battery Management
    • RF Power
    • Resistors
    • Capacitors
    • Magnetics
    • Transformers
  • Applications
    • LED Lighting
    • Rack Mount
    • Wireless
  • EE Forums
    • EDABoard.com
    • Electro-Tech-Online.com
  • EE Learning Center
    • Design Guides
      • WiFi & the IOT Design Guide
      • Microcontrollers Design Guide
      • State of the Art Inductors Design Guide
  • Video
    • EE Videos
    • TI Power Videos
    • Teardown Videos
  • Resources
    • Design Fast
    • eBooks / Tech Tips
    • FAQ
    • LEAP Awards
    • Podcasts
    • Webinars
    • White Papers

Three common mistakes when designing power supplies

February 15, 2013 By Natasha Townsend Leave a Comment

When I posed this question to companies that design power supplies, I thought that I was going to receive varying answers. Surprisingly, these companies tend to agree on the biggest mistakes that engineers/designers make in designing in-plant power supplies. For the purpose of this article , I have used  specifications from a common ATX12V Power Supply Design Guide, as examples to each topic.

Corsair Enthusiast TX750M ATX 12 V (Advanced Technology eXtended) power suuply
Corsair Enthusiast TX750M ATX 12 V (Advanced Technology eXtended) power suuply

1.)  Over or under specifying their total power requirements.

Avoiding this mistake will not only prevent short circuits, but it prevents the other circuitry from being destroyed. Power supplies should be designed to accommodate any increased +12 VDC currents. Under normal or overload conditions, no output shall continuously provide more than 240 VA under any conditions of load including output short circuit, per the requirement of UL 1950/CSA 950 / EN 60950/IEC 950.

2.) Not considering start-up and peak power loads required by motors, pumps, solenoids, etc.

When designing power supplies, accommodations should be made for continuous operation. A power supply shall be capable of supplying full-rated output power over two input voltage ranges rated 100-127 V ac and 200-240 Vac rms nominal. The correct input range for use in a given environment may be either switch-selectable or auto-ranging. The power supply shall automatically recover from an ac power loss. The power supply must be able to start up under peak loading at 90 Vac.

Parameter Minimum Nominal+ Maximum Unit
Vin (115 VAC) 90 115 135 VAC rms
Vin (230 VAC) 180 230 265 VAC rms
Vin Frequency 47 — 63 Hz

 3.) Not fully considering environmental aspects such as dust, humidity, altitude, ambient temperatures, etc.

 All power supplies need ventilation. It is the designer’s choice of a power supply cooling solution, which depends, in part, on the targeted end-use system application(s). At a minimum, the power supply design must ensure its own reliable and safe operation.

These are some examples of what designers aim for:

Temperature

-Operating ambient +10 °C to +50 °C (At full load, with a maximum temperature rate of change of 5 °C/10 minutes, but no more than 10 °C/hr.)

-Non-operating ambient -40 °C to +70 °C (Maximum temperature rate of change of 20 °C/hr.)

Thermal Shock (Shipping)

Non-operating -40 °C to +70 °C, 15 °C/min ≤ dT/dt ≤ 30 °C/min, Tested for 50 cycles; Duration of exposure to temperature extremes for each half cycle shall be 30 minutes.

Humidity

-Operating To 85% relative humidity (non-condensing)

-Non-operating To 95% relative humidity (non-condensing)

-Note: 95% RH is achieved with a dry bulb temperature of 55 °C and a wet bulb temperature of 54 °C.

Altitude

-Operating To 10,000 ft

-Non-operating To 50,000 ft

Mechanical Shock

Non-operating 50 g, trapezoidal input; velocity change ≥ 170 in/s.

Random Vibration

Non-operating 0.01 gÇ/Hz at 5 Hz, sloping to 0.02 gÇ/Hz at 20 Hz, and maintaining 0.02 gÇ/Hz from 20 Hz to 500 Hz. The area under the PSD curve is 3.13 gRMS. The duration shall be 10 minutes per axis for all three axes on all samples.

Acoustics

For power supplies designed for low noise, the following provides some general guidance.

TDK-Lambda SWS 1000L 12 V power supply
TDK-Lambda SWS 1000L 12 V power supply

Guidelines Sound Power: The power supply assembly shall not produce a declared sound power level greater than 4.0 BA. Sound power determination is to be performed at 43C, 50% of maximum rated load, at sea level. This test point is chosen to represent the environment seen inside a typical system at the idle acoustic test condition, with the 43C being derived from the standard ambient assumption of 23C, with 20C added for the temperature rise within the system (what is typically seen by the The declared sound power level shall be measured according to ISO 7779 and reported according to ISO 9296.

Special thanks to Mel Bergman, TDK-Lambda

ATX12V Power Supply Design Guide,

 

Filed Under: Editor's Blog, Featured, Power Supplies Tagged With: Commentary

Reader Interactions

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Primary Sidebar

CURRENT DIGITAL ISSUE

A frequency you can count on There are few constants in life, but what few there are might include death, taxes, and a U.S. grid frequency that doesn’t vary by more than ±0.5 Hz. However, the certainty of the grid frequency is coming into question, thanks to the rising percentage of renewable energy sources that…

More from the digital archive

DesignFast

Component Selection Made Simple.

Try it Today
design fast globle

Subscribe to our Newsletter

The Power Electronic eNewsletter delivers breaking electronic and power component news, resources, product innovations and more.

Subscribe today

EE TRAINING CENTER CLASSROOMS

EE Classrooms

RSS Current EDABoard.com discussions

  • DC DC converter output voltage rise time
  • SMPS topology
  • LLC HB with synchronous rectifiers can be very dodgy?
  • Reducing switching noise in MOSFET inverter
  • Mathematical formula that converts voltage to weight the HX711 is using

RSS Current Electro-Tech-Online.com Discussions

  • Are Cross-wind compensation and Road crown compensation functions inputs to LKA function?
  • 500+V power supply from 9V battery using ZVS
  • IRFP450A replacement with IRFP460N on SIEG X2/LTF058213220 mini drill SIEG-FC350SMD Board
  • Sears Model 10656 Clock Radio - Clock board demanding high wattage resistor?
  • Trying to make a custom automated water container for my UV purifier. Can anyone help with where to begin?

Footer

EE World Online Network

  • DesignFast
  • EE World Online
  • EDA Board Forums
  • Electro Tech Online Forums
  • Connector Tips
  • Microcontroller Tips
  • Analog IC Tips
  • Sensor Tips
  • Test and Measurement Tips
  • Wire and Cable Tips
  • 5G Technology World

Power Electronic Tips

  • Subscribe to our newsletter
  • Advertise with us
  • Contact us
  • About us
Follow us on TwitterAdd us on FacebookFollow us on YouTube Follow us on Instagram

Copyright © 2022 · WTWH Media LLC and its licensors. All rights reserved.
The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media.

Privacy Policy