PowerSource

It’s become part of the lore of science and engineering that an inventor will barely beat out a competitor at the door of the patent office, or a scientist will publish a paper just days before a distant colleague. While some hypothesize that skullduggery was behind the photo-finish (such as this book about Alexander Graham Bell and his telephone patent, or Darwin rushing to publish after seeing Wallace’s rough draft) it’s still clear that when there is an obvious problem or puzzle to solve, bright minds will search for a solution and come up with similar results. An obvious problem just begs for a solution.

So why aren’t there more lithium ion battery pack fuel gauges being introduced? While many IC companies offer the coulomb-counting type of gauge, coulomb-counting technology has some serious negatives: It’s not as accurate as you’d like, and it often requires a learning cycle of charging and recharging the battery cell(s) as part of the production process which adds cost. On the plus side, the coulomb-counting gauges are simple and inexpensive.

The technology behind TI’s Impedance Track family of fuel gauges was announced way back in 2004, with the first products appearing towards the end of last year. In conversations with battery pack designers, I hear almost universally that Impedance Track is becoming the chip-of-choice for higher-end battery packs, often used in laptops or smart phones, that can leverage the gauge’s increased accuracy as an added feature and higher price justification for the end product.

Power management is an intensely competitive IC market segment. Case in point: Several digital power controllers are available, which all were introduced within months of each other. But where are the competitors to Impedance Track? I think (hope) that this summer will finally see some competition emerge.