Nujira Announces New DC-DC Converter Reference Design

October 05, 2009 by Jeff Shepard

Nujira has released a dc-dc converter reference design that delivers up to 95% efficiency and, according to the company, can be manufactured at one-third of the cost of standard designs.

Engineered for use with Nujira’s Coolteq.h™ power modulator modules, the Nujira Coolteq.p dc-dc converter reference design is typically suitable for up to 40W RRH and BTS applications. Coolteq.h modules do not require a highly regulated supply and Coolteq.p was developed specifically to address the opportunity to use a lower cost, high efficiency lightly regulated supply to power the RF subsystem.

Features of Coolteq.p include a 3.3V input terminal for logic circuit supply pass-through, and ample reserve power to allow other system components such as RF drivers, pre-drivers or whole RRH to be supplied via appropriate low-power regulators. According to Nujira, Coolteq.p can be manufactured for around $15, compared with over $45 for a traditional dc-dc converter which is typically less than 90% efficient.

"Unlike traditional analogue PA designs, our Coolteq.h modules don’t need an expensive, highly regulated power supply to meet the stringent adjacent channel noise specifications", said Jeremy Hendy, Nujira’s VP Sales & Marketing. "Our dc-dc converter reference design demonstrates the wider system benefits that Nujira’s Coolteq envelope tracking products bring to designers of 3G and 4G Remote Radio Heads. By removing the need for a highly regulated power supply, our Coolteq.p reference design can operate at 95% efficiency, which is equivalent to adding 3-5 percentage points to the efficiency of the PA output stage."

Coolteq-p operates from a -39 to -60V supply, and offers +24V and +48V unregulated outputs. It can support a total load of 180W, which gives 30W reserve power when used with a Coolteq.h module driven at full power. The efficiency of the converter is 95% at full power, dropping to 93% at 50W. The design offers short and open circuit protection at the input and the output, with an automatic restart within 150ms of the triggering event being cleared. The input and output sections of the design feature 500V isolation.

The Coolteq-p design includes an enable/disable line, to allow the subsystem to be powered down remotely. The footprint is just 62 x 53mm.