Fuel-Gauge ICs Target Mobile and Portable Devices

Maxim Integrated Products has announced the MAX17262 single-cell and MAX17263 single-/multi-cell fuel-gauge ICs. The MAX17262 features just 5.2 µA quiescent current, along with integrated current sensing. The MAX17263 features just 8.2 µA quiescent current and drives 3 to 12 LEDs to indicate battery or system status. Such LEDs are useful in rugged applications that do not feature a display.

According to the company, 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 state of charge (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.

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. The ModelGauge m5 EZ algorithm eliminates the time-consuming battery-characterization and calibration process. A quiescent current of just 5.2 µA for the MAX17262 and 15/8.2 µA for MAX17263 extends run-time, Rsense current resistor (voltage and coulomb counting hybrid) reduces overall footprint and BOM cost, eases board layout

At 1.5 mm × 1.5 mm IC size, the MAX17262 implementation is 30% smaller in size compared to using a discrete sense resistor with an alternate fuel gauge; at 3 mm × 3 mm, MAX17263 is the smallest in its class for lithium-ion-powered devices. The single-/multi-cell MAX17263 also drives LEDs to indicate battery status on a pushbutton press or system status on system microcontroller commands

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.

Maxim Integrated | www.maximintegrated.com

Voltage Regulator Has Low Quiescent Current

Diodes Incorporated has introduced the AP7381. Operating from a wide input voltage spanning 3.3 V to 40 V, this positive voltage regulator offers ultra-low quiescent current and high accuracy, making it well-suited for use in a variety of applications ranging from USB and portable devices to energy meters and home automation.

MFG_AP7381_SOT89The AP7381 is offered with fixed output voltages of 3.3 V or 5 V to power standard logic device supplies and I/O levels and can operate from an input voltage between 3.3 V and 40 V, which covers most common system power rails. The device provides excellent line and load regulation and features a low dropout voltage of typically 1,000 mV for a 3.3 V output device operating at an output current of 100 mA. An internal voltage reference ensures output accuracy at room temperature is maintained within ±2%.

A low quiescent current of just 2.5 µA minimizes standby power in low-power systems and extends the life of battery-operated products. The AP7381 has a built-in current limit and an over-temperature protection (OTP) function and also features over-current protection, provided by an internal current limit circuit. The AP7381 is available in a SOT89 package (on tape and reel) and in a TO92 package (ammo packed).

Diodes Incorporated | www.diodes.com