Configurable convertor aids PCB design and test

A new remotely configurable point-of-load DC/DC convertor from Artesyn Technologies provides powerful control flexibility for PCB design qualification and production test.

A new remotely configurable point-of-load DC/DC convertor from Artesyn Technologies provides powerful control flexibility for PCB design qualification and production test.

The SIL15E-12M nonisolated point-of-load (POL) convertor combines industry-leading conversion technology with next-generation voltage control features.

Based on Artesyn's 15A SIL15E high efficiency POL convertor, the new remotely configurable version incorporates an industry-standard I2C bus interface that simplifies setup and control.

I2C programmable features include precision setting of both the output voltage and voltage margining facilities.

In addition, an active DC output control function significantly increases output voltage accuracy during normal operation and when voltage margining during system test.

Intended primarily for high-end applications in the telecommunication and data communication markets, SIL15E-12M is the latest addition to Artesyn's E class family of high efficiency, general-purpose POL convertors.

The company will continue to introduce convertors with increasingly flexible power management facilities, as the market for intelligent power products evolves.

SIL15E-12M POL convertors have an input voltage range of 10 to 14V and an exceptionally wide 0.8 to 3.36V output range, enabling a large number of different device supply requirements to be satisfied with just the one model.

The convertors use a synchronous buck regulator topology with precision synchronous rectifier timing, and can generate up to 15A with a very high full load efficiency of 92%.

Artesyn has significantly extended the convertor's functionality by integrating a programmable active DC output control function.

During product development, the convertor's voltage set-point can be programmed - via the built-in I2C interface - to a very high degree of accuracy, and the active control function will maintain this setting very precisely during normal operation, by automatically compensating for different load conditions.

The same function is used when performing voltage margining during production test, to ensure accurate results and prevent devices being over-stressed.

Each convertor is supplied preprogrammed to standard default values stored in non-volatile memory and only requires additional programming by customers if they wish to change an operational function.

During product development, designers can program various functions of the convertor to check board operation before locking in final parameters for production, thus reducing both development time and risk.

For example, designers could alter the convertor's output voltage to overcome small distribution losses, change voltage margining limits, or examine the effect of switching the active DC output control function off.

By default, the convertors are supplied with +/-5% margin limits and with the output control function on.

The latter facility uses advanced techniques to maintain the output set-point very accurately - typically within +/-0.75% - over time and under different temperature and load conditions.

Programming the POL convertors on a board under development is simply a case of connecting its I2C bus connector via a USB cable to a standard PC running a Windows based configuration GUI (graphical user interface).

SIL15E-12M convertors can be controlled independently or up to eight can be addressed simultaneously.

The configuration software employs an intuitive, simple to use interface to minimise system prototype development time.

Voltage margining (varying the supply voltages to ICs on a board) is a technique commonly used by design engineers during product development and qualification, to check the susceptibility of a device to move outside specification - or fail - under worst-case supply conditions.

Board manufacturers are now beginning to demand that the same technique is used during production test, to prevent faulty devices causing early field failures.

At present, designers accommodate this requirement by adding external components to each POL convertor.

This approach suffers from numerous disadvantages: it increases component count and cost, occupies valuable board space, involves a considerable number of extra tracks on the board, and does not provide sufficient resolution for accurately testing today's very low voltage silicon devices.

The I2C-controlled margining facilities of SIL15E-12M POL convertors provide an elegant solution for all these issues by obviating the need for external trim resistors or FETs.

Instead, automatic test equipment (ATE) can be used to command operation of voltage margining via the board's I2C bus.

The upper and lower margin limits will previously have been programmed into the convertor's non-volatile memory, which means that the ATE merely needs to invoke the appropriate operation during test.

Artesyn chose to use the I2C bus because it is an open-architecture solution widely supported by semiconductor manufacturers, and is already used extensively for control, monitoring and diagnostics - especially in telecomms applications.

And its simple two-line structure can be easily routed to all the POL convertors on a board without raising design layout issues.

Furthermore, because each POL convertor is individually addressable, it provides a very flexible foundation for future power management developments.

SIL15E-12M POL convertors employ an open-frame, single-board construction to minimise cost and weight and simplify thermal management.

Designed for through-hole vertical mounting, the convertors feature single-inline connections, have an industry-standard footprint of just 2.0 x 0.33in, and an above-board height of 0.5in.

Their low installed height makes them particularly suitable for telecomms applications that use tight interboard rack spacing to minimise system size.

Artesyn's SIL15E-12M POL convertors accommodate a wide operational temperature range of -40 to +85C ambient, with derating, and are expressly designed as high reliability products with an MTBF in excess of 3.5Mh (in accordance with Telcordia SR-332).

The convertors feature remote sense and remote on/off facilities, have no minimum load requirement, and are comprehensively protected against overtemperature and short-circuit conditions.

They carry a full set of international safety approvals, including EN60950 (TUV Product Service) and UL60950.

To help engineers familiarise themselves with these advanced POL convertors, Artesyn is making an evaluation kit available.

The boxed kit comprises two SIL15E-12M POL convertors mounted on a PCB with an I2C bus connector, a USB cable to connect the board to a PC, a CD-ROM containing the configuration software and installation instructions, and a printed copy of the user guide.

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