CamSemi has announced a breakthrough in the Primary Side Sensing (PSS) market, following on from the success of its C2470 series of Resonant Discontinuous Forward Converter controllers that were launched in late 2007. The new C2140 series offers ‘best in class’ current and voltage regulation of +/- 5% and targets high volume, universal input applications rated up to 8 W. The parts also feature easily programmable cable compensation and switching frequency adjustment to enable greater design and manufacturing flexibility.

These novel PSS controllers will help manufacturers of chargers for mobile phones, Bluetooth headsets, digital cameras and other high volume consumer products to cut component count, while developing more reliable and lower-cost designs to meet Energy Star 2.0, European code of conduct and other worldwide energy-efficiency regulations. The C2141PX2 and C2142PX2 parts are rated at 4 W and 8 W respectively, packaged in SOT23-6 and are available in volume now.

CamSemi’s C2140 family completely eliminates the need for optocouplers and all secondary-side feedback circuitry, as well as any additional components that designers may need to specify to improve the current regulation from a typical PSS flyback design. The controllers use sophisticated patented algorithms combined with digital techniques to more accurately monitor the output voltage and provide tighter current regulation than has previously been possible. This novel approach enables quasi zero voltage switching, which drives up operating efficiencies and delivers improved current regulation to maintain the optimum lifetime of lithium ion batteries.

The new devices include easily programmable cable compensation of up to 10% to give tight voltage regulation at the end of the cable, while helping to minimise the copper content (and therefore cost) of the cable. The compensation is fully adjustable in the design phase allowing one standard design to be quickly modified to accommodate different cable lengths or gauges. The controllers can also be easily adapted to match the required switching frequency of the end application by simply specifying one external component.

“CamSemi’s new products not only offer the best current regulation of any PSS controller on the volume market today but have been specifically designed to give manufacturers much more freedom in optimising often conflicting design and production requirements. Our ‘one size fits all’ approach means one controller can meet a range of cable compensation and switching frequency requirements and without manufacturers having to maintain inventory of multiple parts,” said David Baillie, CEO of CamSemi.

CamSemi C2140 controllers are designed for use with low cost bipolar transistors and have protection features such as over-temperature, input over-voltage and output short-circuit included as standard to further simplify designs and reduce system costs.

An abbreviated datasheet for the C2140 family is available online at www.camsemi.com with more detailed information and support direct from CamSemi or one of the company’s distributors.

Cambridge Semiconductor, Ltd.
St Andrews House
St Andrews Road
Cambridge CB4 1DL
United Kingdom
Phone Direct : +44 (0)1353 741075
Mobile : +44 (0)7810 795035
Fax : +44 (0)1353 749519
Email: : simon.mckay@camsemi.com
web : www.camsemi.com