RF transmission specialist, Nujira, hopes to enhance base station efficiency and cut costs with a new DC-DC converter reference design said to deliver up to 95 per cent efficiency.
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 -39V 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/ isable line, to allow the subsystem
to be powered down remotely. The footprint is just 62 x 53mm.