Fuel gauge eliminates the need for battery characterisation

31st May 2016

Nat Bowers

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Datasheet

Easing and securing the implementation of pack-side battery gauges in portable devices, the ModelGauge m5 portfolio has been announced by Maxim Integrated Products. The MAX17201/MAX17205 and MAX17211/MAX17215 fuel gauges are claimed by the manufacturer to be the industry’s first to integrate SHA-256 for secure authentication to prevent battery clones.

Fuel gauging can be difficult because battery voltage varies with temperature and load, while coulomb-counting requires sophisticated compensation to eliminate offset accumulation errors. Maxim’s ModelGauge m5 fuel gauges include a sophisticated algorithm that converts raw measurements such as battery voltage, current, and temperature into accurate state-of-charge (SOC%), absolute capacity (mAhr), time-to-empty and time-to-full (while charging), all of which improve the user experience of the host device while enabling maximum run-time. To ease the design process, the ModelGauge m5 EZ configuration eliminates the time and resource-consuming characterisation process for a large number of battery types.

Battery packs generally need to be replaced every few years - when batteries age, their characteristics change over time and no longer provide adequate run-time. The ModelGauge m5 robust algorithm detects the smallest changes in the capacity of the battery to more accurately predict how long the battery will last before the capacity degrades rapidly. With the Cycle+ age forecast information from ModelGauge m5 fuel gauges, system designers are able to adjust charger parameters to extend the battery life or to plan a timely replacement of the battery. Maxim’s ModelGauge m5 portfolio of products are suited for any rechargeable battery operated device, such as wearables, drones, tablets, smartphones and other IoT applications.

The ModelGauge m5 fuel gauges offer low quiescent current of 9µA (MAX17201/MAX17211) and 12µA low-power operation (MAX17205/MAX17215) and operate over a temperature range from -40 to +85°C.

Bakul Damle, Mobile Power Business Management Director, Maxim Integrated, commented: “From decades of battery management and cryptographic design experience, Maxim is bringing world-class fuel gauge accuracy and security to all customers, from large manufacturers to start-ups and makers. Our ModelGauge m5 EZ products allow designers to focus on what they’re good at and not have to worry about gas gauge implementation.”

Supplied in a 14-pin TDFN package measuring 3x3mm, the MAX17201, MAX17211, MAX17205 and MAX17215 fuel gauges are priced from $1.39 each in 1,000 unit quantities. The MAX17201GEVKIT, MAX17205GEVKIT, MAX17211GEVKIT and MAX17215GEVKIT evaluation kits are also available.