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Supercapacitor Auto Balancing MOSFET Arrays Control and Balance Over-Voltage With Near Zero Leakage

Precision SAB™ MOSFET arrays lower cost, reduce space and boost efficiency for industrial, transportation, mobile and energy harvesting applications

SUNNYVALE, Calif. November 19, 2013 - Advanced Linear Devices Inc. (ALD), a design innovation leader in analog semiconductors, today announced a family of Supercapacitor Auto Balancing (SAB) MOSFETs to provide automatic active leakage current regulation and self-balancing of supercaps connected in a series stack. For circuit design in automotive batteries, industrial engines, mobile or energy harvesting applications, ALD’s SAB MOSFET arrays eliminate both overcharging and excessive power dissipation to preserve lifespan of supercap and battery components.

Available in both quad and dual packages, the ALD8100xx/ALD9100xx SAB MOSFETs, made with ALD’s precision EPAD® technology, offer a superior alternative to other auto-balancing schemes based on passive resistors or operational amplifiers, which contribute continuous power dissipation due to linear currents at all voltage levels. Additionally, the SAB MOSFETS lower cost and power consumption and reduce board space.

Leakage differences in series-connected supercaps make it difficult to control respective voltages. This causes one or more supercap to exceed its rated voltage over time, which reduces lifespan through rupturing and leads to catastrophic failure.

The ALD8100xx/ALD9100xx SAB MOSFET family offers different threshold voltages for various supercap nominal voltage values and desired leakage balancing characteristics. By increasing drain current exponentially when voltages increase, and by decreasing drain current exponentially when voltages decrease, the MOSFET arrays regulate the voltage across a supercap cell.

“Each supercapacitor cell has a definitive maximum set voltage. However, when two or more are connected in series, it becomes difficult to control the leakage of each cell, resulting in voltage imbalance that causes one or more cell to rapidly degrade,” said Bob Chao, President of ALD. “Steady degradation of one or more of the supercaps will cause them to reach a failure point. The intrinsic qualities of SAB MOSFETS, are ideally suited to balance the supercaps and prevent the damage of excessive voltages.”

ALD SAB MOSFETs have unique electrical characteristics for active continuous leakage current regulation and self-balancing of stacked series-connected supercaps. Additionally, they are designed to dissipate near zero leakage currents, eliminating extra power dissipation.

Supercapacitor technology is gaining traction in the transportation industry because of the ability to extend the life, and reduce cost of batteries by improving reliability. In mobile applications supercaps can also regulate peak voltages and greatly improve talk time. The market for supercapacitors could grow more than 126% over the next five years to reach $836 million, according to a forecast by Lux Research.

Pricing and Availability: The ALD8100xx/ALD9100xx SAB MOSFET family is available in industry standard 16-Pin/8-Pin SOIC packages. 1,000-piece pricing starts at $1.12 each.

About Advanced Linear Devices, Inc. Advanced Linear Devices, Inc. (ALD) is a design innovation leader in analog semiconductors specializing in the development and manufacture of precision CMOS linear integrated circuits, including analog switches, A/D converters and chipsets, voltage comparators, operational amplifiers, analog timers, and conventional and precision EPAD MOSFET transistors.
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