AFEs Double Accuracy and Reduce Battery-Management Systems Cost up to 35%

Maxim Integrated Products, Inc. is sampling the MAX14920/MAX14921, high-accuracy, 12/16-channel cell-measurement analog front-ends (AFEs) that lower battery-management electronics costs by up to 35%. These devices double the accuracy of cell voltage readings through the use of high-accuracy common-mode level shifting and an integrated high-precision amplifier that simplifies ADC data conversion. Higher accuracy improves state-of-charge determination and cell balancing that in turn lengthen the life of rechargeable Lithium-ion (Li+) battery packs and maximize available energy, especially important for modern battery chemistries that exhibit flat voltage discharge curves, such as those with LiFePO4 cathodes.

The MAX14920/MAX14921 enable the industry’s highest accuracy cell voltage measurements (±0.5mV, max). Ideal for 48V to 65V pack voltages required in uninterruptible power-supply (UPS) systems, smart grid energy-storage packs, and telecom power backup-battery packs, the MAX14921 eliminates up to two 6-channel AFEs required for 13S-16S channel battery packs.

These devices can increase individual cell accuracy, thereby improving cell balancing. A single chip supports battery management of up to 16 cell packs. And these devices provide a flexible solution since they are suitable for use in both lower cost applications (using the ADC integrated in a microcontroller) and higher accuracy applications (utilizing an external ADC).

“We strategically integrated only the cell voltage sampling and a high precision amplifier to optimize accuracy, while also enabling system flexibility,” said Tim Leung, Business Manager at Maxim Integrated. “With a flexible battery-management system (BMS) design that can be reused from 3 to 16 channels, we enable optimized front-end solutions based on individual system requirements and cost. This also provides a time-to-market advantage.”

The MAX14920 is available in a 64-pin (10mm x 10mm) TQFP package. Pricing starts at $5.04 (1000-up, FOB USA). The MAX14921 is available in an 80-pin (12mm x 12mm) TQFP package, with pricing starting at $6.15 (1000-up, FOB USA). Both devices operate over the -40°C to +85°C extended temperature range.