350W Sirius - same footprint but much more power

Lambda has upped the output power of its Sirius range of advanced configurable power supplies.

Lambda, the Ilfracombe-based power supply manufacturer, has upped the output power of its Sirius range of advanced configurable power supplies with the introduction of a new 350W model aimed at applications such as data processing, telecoms, industrial equipment, test equipment and instrumentation.

Comments Martin Southam, Lambda's UK sales director: "The new Sirius 350 complements the existing 250W unit.

By keeping the footprint of the new unit the same as that of the 250W Sirius we have effectively given designers a scaleable power solution.

This is particularly important in instrumentation and test equipment where different functionality within the same basic design often results in different power requirements.

A scaleable power solution means that a major redesign is now no longer required when more power has to be provided.

With Sirius the designer simply replaces one unit with another!" Dimensions are 227.5mm long, 127mm wide and 63mm high for the system cooled versions.

The 350W Sirius combines highly innovative technology with the latest design-for-manufacturing techniques to produce a power supply which although technologically advanced is also very competitively priced.

"The novel design features give us a unit with extremely good thermal efficiency," said Southam.

"This means we can offer a 350W model with a relatively small cost increase over the 250W version, making it one of the most competitive units of its kind".

The user can choose between one and six configurable outputs, ranging from 1.8V to 28V DC.

Up to 80V DC can be achieved by series connection.

The unit has no minimum load requirement and AC input is 90 to 264V.

The innovative core of the new power supply is its unique planar transformer which was designed in-house by Lambda engineers.

Rather than using secondary windings, FR4 secondaries and copper stampings for high current outputs, are 'slotted' into the moulding.

The actual number of secondaries varies according to the output requirement.

Primary/secondary insulation is accomplished with triple insulated wire primaries wound onto the ends of the moulding.

The open construction of the transformer brings a number of benefits.

The spacing between the secondaries, created by the moulding, reduces interwinding capacitances and thus reduces output noise and improves the supply's RFI performance.

The planar design is slightly more 'lossy' but its open construction gives Sirius a lower transformer operating temperature than would otherwise be achieved by more traditional designs.

And, although the transformer has a slightly higher material content, the cost is more than offset by production savings.

Another innovative part of the Sirius design is the unit's power factor correction circuit.

Sirius employs active power factor correction and its PFC circuit uses a conventional PWM IC rather than a dedicated PFC chip which brings significant cost savings.

The active design enables Sirius to achieve a PFC of more than 0.95, significantly better than passive PFC, and provides harmonic correction in accordance with EN61000-3-2.

The Sirius 350 employs a two-transistor forward converter topology, with a closed loop on the main output.

Module good, AC fail, remote sense and inhibit are all standard features, as are short circuit protection on the output modules and thermal protection.

Sirius can quickly and easily be connected/disconnected via Faston output connectors and a choice of Molex or IEC style input connectors.

The low profile and streamlined mechanical design of Sirius coupled with the unit's 'cool running' transformer means that it requires an extremely low air flow.

As a result the unit can utilise the cooling mechanisms present in the OEM equipment into which it is installed, or alternatively it can be supplied in a case with a single top fan or end-mounted 60mm fans for height restricted applications.

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