Is a custom power supply the right option
for your current project?
A custom power supply can be the right option if you need:
- small size or special form factor to fit your system.
- rugged or extended temperature range.
- high reliability and long life.
- special performance such as very low noise or leakage current.
- a replacement for an obsolete COTS unit.
- unusual output voltage.
Advantages of custom design
- You get exactly what you need, rather than adjusting your system design around what's available off-the-shelf.
- You can reduce other system components (e.g. fans) and related costs
- A custom power supply gives you greatest flexibility to optimize the overall mechanical design.
- You get a power supply to fit your space, rather than designing around a fixed form factor.
Drawbacks of custom
...and how to reduce your risk
Custom is more expensive
...going custom is not the way to get a cheaper power supply unit.
However, it can reduce overall system costs by reducing complexity
of the rest of your board design.
It will be sole-sourced
...reduce your risk by choosing a vendor that guarantees long-term support.
BEAR has never "obsoleted" a power supply and is currently supporting custom
products that are nearly 20 years old.
...compare the risk of sole-sourcing to the risk of rapid obsolescence in
major vendors' standard product lines.
It can take longer
...reduce your risk by communicating well with your vendor.
Should you design your own power supply?
Unless you have expertise in power supply design, probably not. Most times this is just
not as cost-effective as using a power supply specialist. We recommend
the article "Make vs. Buy"
(PDF) by Kevin Parmenter of ON Semiconductor
(originally published on the
PSMA web site).
The author states:
"...over the years I have observed many companies attempt to design their own power
systems and power supplies. Some have been successful but many have incurred large expenses
and wasted precious time to market because they simply do not know how to design power supply
systems which are stable, reliable, and manufacturable in high volume and operate over long periods of time. WHY?"
Download the article,
"Make vs. Buy" (169Kb pdf).
Tips for a successful custom project
Over the years of custom power supply design projects, we have found five things that
customer engineers most often forget to tell us. Discussing these issues up front will help
us meet your needs with the first prototype.
- The "real" operating temperature. If the PSU is in an enclosed box, this is higher
than the ambient temp your system will see.
- The type of load - especially motors (inductive sine waves), digital logic
that may be poorly filtered, or DC/DC converters (which tend to pull short, large current pulses from the AC/DC supply).
- Expected lifetime. Your expectations will determine quality and cost of the components we use in the power supply.
- How clean is the input line? Will there be high voltage transients (e.g. from lightning)? Will there
be power dips from large machinery (e.g. compressors, motors, welding machines) on the same phase as your system?
- Environmental factors such as shock, vibration and humidity.
Let us know the environment and we can design with it in mind - for example, for portable systems we
can choose low-profile components and use potting or conformal coating if possible.
Download the complete article,
"How to spec a reliable custom power supply: 5 essential tips; (237Kb pdf).
The bottom line: talk to BEAR
We can save you time and money on your power supply design,
and deliver greater performance. The more information we have about your intended application and
environment, the better we can strike the right balance of performance and cost to meet your needs.
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