Battery Fuel-Gauge ICs Deliver Lowest Operating Current

Designers of lithium-ion (Li-ion) battery-powered mobile devices such as wearables, electric bicycles, power tools and internet of things (IoT) products can improve the end-user experience by extending run-time and delivering accurate battery state-of-charge (SOC) data with the MAX17262 single-cell and MAX17263 single-/multi-cell fuel-gauge ICs from Maxim Integrated Products, Inc.

The MAX17262 features just 5.2µA quiescent current, the lowest level in its class, along with integrated current sensing. The MAX17263 features just 8.2µA quiescent current and drives 3-to-12 LEDs to indicate battery or system status, useful in rugged applications that do not feature a display.

Designers of electronic products powered by small Li-ion batteries struggle to extend device run-times to meet user expectations. Factors such as cycling, aging and temperature can degrade Li-ion battery performance over time.

Inaccurate SOC data from an unreliable fuel gauge forces the designer to increase the battery size or compromise the run-time by prematurely shutting the system down, even if there is usable energy available.

Such inaccuracies can contribute to a poor user experience due to abrupt shutdown or an increase in device charging frequency. Designers also strive to get their products to market quickly due to competitive demands. Maxim's two new fuel-gauge ICs help designers meet end-user performance expectations and time-to-market challenges.

The MAX17262 and MAX17263 combine traditional coulomb counting with the novel ModelGauge™ m5 EZ algorithm for high battery SOC accuracy without requiring battery characterization. With their low quiescent current, both fuel-gauge ICs prevent current loss during long periods of device standby time, extending battery life in the process.

Both also have a dynamic power feature that enables the highest possible system performance without crashing the battery.

• In the MAX17262, an integrated Rsense current resistor eliminates the need to use a larger discrete part, simplifying and reducing the board design.
• In the MAX17263, the integrated, push-button LED controller minimizes battery drain and alleviates the microcontroller from having to manage this function.

Key features

• High Accuracy: The ICs provide accurate time-to-empty (1%) and time-to-full SOC data across a wide range of load conditions and temperatures, using the proven ModelGauge m5 algorithm
• Fast Time to Market: The ModelGauge m5 EZ algorithm eliminates the time-consuming battery-characterization and calibration process
• Extended Run-Time: Quiescent current of just 5.2µA for the MAX17262 and 15/8.2µA for MAX17263 extends run-time
• Integration: Rsense current resistor (voltage and coulomb counting hybrid) reduces overall footprint and BOM cost, eases board layout
• Small size: At 1.5mm × 1.5mm IC size, the MAX17262 implementation is 30 percent smaller in size compared to using a discrete sense resistor with an alternate fuel gauge; at 3mm × 3mm, MAX17263 is the smallest in its class for lithium-ion-powered devices
• LED Support: The single-/multi-cell MAX17263 also drives LEDs to indicate battery status on a pushbutton press or system status on system microcontroller commands

"With these industry-leading ICs, Maxim solves many of the conflicting and difficult battery-management challenges faced by designers of portable products," said Bakul Damle, director of business management, Mobile Solutions at Maxim Integrated. "Maxim fuel-gauge ICs empower design innovation that leads to longer run-times for small mobile and portable devices through industry-leading features and functionality."

The MAX17262 is available at Maxim's website for $0.95 (1000 pieces, FOB USA); the MAX17263 is also on the site for $1.49 (1,000 pieces). Both parts are also available via select authorized distributors.

The MAX17262XEVKIT# evaluation kit is available for $60; the MAX17263GEVKIT# is available for $60

Support includes the MAX1726x ModelGauge m5 EZ User Guide and Software Implementation Guide, as well as Linux drivers.