Thin double-layer capacitor powers LED flash units

September 25, 2012 // By Christoph Hammerschmidt
Murata announced production start of the world's thinnest electric double-layer capacitors (DMF Series) featuring low resistance and the highest levels of power density throughout the industry, a benefit when used as an auxiliary power supply for LED flash units.

Electric double-layer capacitors are capable of storing energy with physical adsorption of the ion on the surface of active carbon without using chemical reactions, which makes them devices that are not only able to semi-permanently repeat electrical charging and discharging in comparison with normal rechargeable batteries, but also able to be charged and discharged rapidly. They also do not use lead or any other toxic substances, and because of this they are attracting much attention as storage devices that conform to the Restriction of Hazardous Substances Directive (RoHS) covering electric and electronic equipment established by the European Union, etc., thereby placing minimal burden on the environment.

Murata acquired this technology from Australia's CAP-XX Ltd. ; the business partnership established in 2008 has resulted in Murata manufacturing the DME series of electric double-layer capacitors since December 2010.

The DMF series features an optimized internal configuration to realize a design approximately 30% more compact than the DME series, making the DMF it the thinnest of its type in the world. The DMF also features the highest levels of power density in the industry and the same low resistance of a few dozen milliohms and stable temperature characteristics as the DME series, enabling it to be charged and discharged flexibly through high-output and low-output areas in a wide variety of temperature ranges. The capacitors can be used as the power supplies for camera flashlights utilizing high-intensity LEDs, and will contribute to improving the brightness of LED flashlights on not only digital cameras, but also on smartphones.

With its low Equivalent Series Resistance (ESR) of just 40 to 90 milliohms, the capacitor enables high-current and high-output charging and discharging. It is rather small - According to Murata it is 30% smaller than the DME series. At the same time, the DMF series represents the world's thinnest electric double-layer capacitor.

Besides usage as auxiliary power source for LED flash units, Murata targets applications such output