Power Integrity in Interconnect Design

The need for high-current power interconnect solutions in
increasingly smaller spaces continues to rise rapidly. As demand grows for more
power in smaller packages, solving the power equation on new architectures and
system platforms can pose electrical and mechanical design challenges for OEM
system and power engineers charged with specifying interconnect components that
ensure both signal and power integrity.

Unlike signal connectors, which continue to get smaller at higher
transmission speeds, power connectors require a specific amount of conductive
material to carry specific amounts of current or amperage. There are no special
secrets to design that will allow smaller power contacts to carry more current
- as power needs increase, so does the amount of space needed for higher
ampacity interconnects.

Design Density and Power
Handling

Even though new system
designs often require more power to travel across a limited amount of space,
several factors still affect the density of a design and how much power it can
actually handle. A clear understanding of each of these elements is critical to
successfully designing power integrity and safety into the system - and will
help streamline the overall design process. These key factors include:

Balancing Space and Power. First, it is necessary to determine how much
space is required for a power interconnect versus how much available space has
been allotted in the finished product design. While saving space is a high
priority for most OEMs, the height, width and length of the connector, and
particularly its copper content, will directly affect the achievable current
density. System architects always want to get more power in the same space,
which can pose a challenge for connector manufacturers.

Power Integrity  in Interconnect Design

However, leading global
connector manufacturers continue to develop new and innovative designs that use
higher conductivity materials and utilize space more creatively to improve
power delivery and electrical performance without expanding space requirements.
For example, in some cases, a lower profile connector may be preferable to
maximize air flow for cooling. In other cases, a taller connector offering
improved contact performance may be the right solution to properly handle the
amount of current generated in less card edge space. What's important is
striking the optimal balance of power and its resultant thermal effects in the
PCB with the spatial design requirements to ensure the end product's safety and
performance.

Thermal Management. Thermal issues caused by contact or constriction
resistance and inefficient air flow are always a concern and should be
carefully considered early on in the design process. PCB copper content is one
element of this. Too little copper can restrict current flow, causing
constriction resistance. Appropriate copper trace sizes decreases bulk resistance,
allowing for cooler temperatures and less loss. Otherwise that heat could be
"sinked" to the connector interface, increasing reliability concerns. Power
supply manufacturers are very creative in supplementing PCB structures with
features to alleviate thermal and constriction concerns.

In addition, as systems are
packaged into smaller boxes with more components, it is critical to ensure
proper management of air flow around connectors positioned at the intersection
point (such as between a power supply and

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