A Scalable Low-Cost Alternative to ‘Off the Shelf’ Power Supply Modules
‘Off the Shelf’ (OTS) AC-DC power modules are great… aren’t they?
The value of an OTS module is that it’s easier to design into the end equipment and it’s safety certified, ultimately resulting in faster time to market. There are also numerous suppliers with a range of options and configurations, although these are rarely pin-to-pin compatible for obvious reasons!
However, there are often downsides:
Performance: Modules designed for a range of power options may not be optimal for a particular configuration, so enhancements can usually be found, although this often requires looking beyond the datasheet. A good example is PSU efficiency and Eco-Design standby power efficiency. In the past, there have been cases where PSUs were certified with forced-air cooling disabled to reduce standby power for spot compliance testing, even though this isn’t a user option or a real-world use case.
Features: Taking an existing product can mean you end up with features that aren’t required — examples might include extra outputs and MCU configurability. Alternatively, the product may not have all of the features required, resulting in additional ancillary circuitry that exacerbates pricing challenges as volumes scale.
Price: The common downside is price. For faster time to market, modules purchased through catalog distributors are often a great solution, even with the considerations above. They’re costly in low volumes, but this usually works with initial business models. The challenge comes as the business grows, driving a need for cost reduction — and module volume pricing doesn’t always scale with business needs.
As a power supply expert with over 50 years’ experience designing and supplying PSUs to leading global brands, Salom offers a solution to these challenges with custom pin-to-pin modules.
The advantage of a custom PSU PCBA is that it can be quickly designed for optimum performance, removing or adding specific features as determined by the existing system design and end-product roadmap. Most importantly, there’s little or no NRE required for tooling or safety compliance when the product is certified, since the product is certified with the end equipment and re-certification is managed by the customer — resulting in an optimised, cost-effective product that’s fully under the customer’s control.
A recent example involved a customer using a Mornsun LD30-23BxxR2 Series product that lacked the full temperature-monitoring features they required. The application also called for a higher Pollution Degree 3 rating, and the product’s lifetime needed extending to a minimum of 7 years for higher-temperature performance.
Note: Pollution Degree levels are classifications defined by IEC 60664-1 to describe the environmental contamination and moisture around electrical insulation, which directly determine the required creepage and clearance distances. A design for a higher PD level is therefore built to operate in a harsher environment.
The end result was a custom pin-to-pin PCBA with additional temperature-sensing features, an extended ambient operating range from +80°C to +125°C, and an MTBF increased to 600,000 hours (calculated in accordance with the British Telecom Handbook of Reliability Data Issue 5 [HRD5], or Telcordia SR332 [Bellcore TR332] prediction methods, at ground benign conditions). It also achieved a lifetime of 11 years at the customer’s defined operating profile and ambient test conditions — all for a ~40% price reduction on the existing module at volume production!
Salom SSW-3697 Power Module PCBA
So, is this approach ideal for everyone?
Due to the NRE involved in design and production set-up, this approach is best suited to volumes of 5k units+/year, although lower volume engagement is feasible where there’s a clear business plan to scale. The customer will also need resources to oversee end-equipment compliance testing, including the PSU. Full pre-compliance testing reports — including ESD per IEC 61000-4-2, and conducted and radiated EMC emissions to CISPR 14 — can be provided, along with additional custom testing to meet specific customer requirements.
If you believe this fits your needs and you’re looking for a power supply partner to help you reach these goals, we’d love to discuss your project.
Andy Richardson – CEng MIET, info@salomeurope.com Vice President Business Development, Salom Europe Ltd
About Salom: Salom is a leading global volume manufacturer of high quality power solutions for a range of markets. As a manufacturing partner for global brands, Salom has produced in excess of 3Bn power supplies since its formation. Salom products are trusted by some of the most successful electronics companies in the world, quietly and efficiently powering devices across the globe for more than 50 years.