Optimizing PSU Power for Advanced CPE

NetBit PSU

Diminishing, Oversized and Overpriced

We are moving into an age where the method for defining CPE PSU power output is changing. Old methods are becoming obsolete due to conservative power budgeting which leads to designs which are too expensive, too big or both. Cutting edge CPE devices now feature more transient (or on demand) features relative to functions which draw continuous load. NetBit has opened the door for a new way of defining PSU power output that can help customers save money and reduce PSU size.


Out with the Old

A PSU’s power budget was normally defined by adding up all the power requirements of the individual hardware functions for both typical and peak consumption. This end figure would then dictate the level of nominal power output required.

Whilst this method is a safe ‘belt and braces’ approach it can lead to over-specifying the PSU’s power output which can result in a larger and more expensive PSU. There is now an alternative approach to defining the power output for the newer range of advanced CPE products.


A New Way to Define PSU Power Output

New CPE products such as DCOSIS 3.1 and GPON gateways have common HW features that from a power consumption perspective can be put into one of two categories:

  1. Steady state or continuous load
  2. Transient or on-demand load

An example of steady state features include the main processor which is either on or off and, generally speaking, consumes the same amount of power when it is on regardless of how busy it is. Transient loads include WiFi, radios, telephone ringers, audio amplifiers and speakers whose power consumption is on-demand and at different loads.

There is a trend emerging for more transient features in CPE products. Recognizing this, NetBit is developing PSUs with a higher ratio of transient power capability relative to the continuous load. This creates a new opportunity for OEMs and operators to redefine power budgeting for next generation CPE products.


New high transient power PSU designs

NetBit’s new range of high transient power PSUs can be customized to give customers a bespoke power solution optimized for cost and size for their individual applications. NetBit do this by working with customers to understand the continuous and transient power loads and modifies the PSU output accordingly so that it’s perfectly matched to the end application.

For example, take a typical DCOSIS 3.1 Telephony Gateway. Dividing the power consumption between continuous and transient might show the continuous load requirement to be around 30W with an additional transient load of 16W (total 46W peak) to support the unlikely usage case of simultaneous ringing on two telephony lines. NetBit would customize a 30W rated PSU to have a transient output of 16W and the resulting design would be significantly more cost effective and smaller than a 46W rated PSU.


Immediate Benefits for this Type of PSU Design

There are several significant advantages with this new approach that immediately benefit the customer:

  • Lower Cost – reducing the maximum continuous load lowers the cost of the PSU
  • Reduced Size – optimizing the power output can reduce the power density required for smaller form factors or customized PSU enclosures, benefits to packaging and shipping costs
  • Lower component temperatures – lowering the maximum continuous rated load reduces the internal temperature rise which in turn allows for smaller form factor


If you’re interested in learning more about this type of PSU design or you have a particular application you want to discuss, contact NetBit here.