Power controllers dither for EMC compliance

Edited by the Electronicstalk editorial team Oct 31, 2007

Dithering the switching frequency by +/-12% produces a spread spectrum that reduces peaks in electromagnetic interference.

A new series of high-voltage synchronous buck controller ICs from Micrel offers a frequency dithering feature to minimise EMI and help designers meet global EMC standards.

Targeted at the industrial, communication, automotive and high-end consumer markets, the solutions are ideal for high-voltage and high-efficiency point-of-load systems, including printer head drivers, gaming applications and mobile entertainment systems.

The ICs are currently available in volume quantities, with pricing starting at US $1.63 for 1000-unit quantities.

"Industrial, automotive and medical applications have rigorous quality and performance specifications that frequently require the lowest possible EMI and tolerance to high input voltages", says Ralf Muenster, Micrel's Marketing Director for Power Products.

"In order to meet global EMC specifications, Micrel's MIC2131 features a +/-12% switching frequency dithering to produce a spread spectrum thereby lowering the EMI peaks".

"In addition, the synchronous operation gives designers the highest possible efficiency with the best performance for a variety of FETs".

The MIC2130/1 operates over a wide input voltage range of 8 to 40V and offers adjustable output voltages down to 0.7V.

The device features a 150kHz frequency option, available now, which allows optimisation for best efficiency or size.

The solution also offers internal drivers for output currents up to 15A and an adaptive gate drive allows efficiencies of more than 95%.

The ICs provide better than 2% output voltage accuracy over -40 to +125C and excellent line and load regulation thanks to a fast hysteretic control loop during transients.

The MIC2131 has advanced current limit protection which allows for increased current when powering highly capacitive loads quickly.

The ICs are available in a 150kHz, 16-pin e-pad TSSOP option today.

The 400kHz frequency option and the MLF-16 4 x 4mm package option will both be available in the first quarter of 2008.