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 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.
Key Features
-Highest accuracy: increases individual cell accuracy; improves cell balancing.
-Lower cost: one chip supports battery management of up to 16 cell packs.
-Flexible solution: suitable for use in both lower cost applications (using the ADC integrated in a microcontroller) and higher accuracy applications (utilizing an external ADC).
Commentary
-“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 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.”
-“Battery management solutions are growing 10% a year due to the need for secure power for cloud servers. Maxim’s new solution fills a need for that market where cost and time to market is becoming more important,” said Susie Inouye, Research Director at Databeans, a market research firm tracking power management.”
Availability, Pricing, and Temperature Range:
MAX14920
-Available in a 64-pin (10mm x 10mm) TQFP package.
-Pricing starts at $5.04 (1000-up, FOB USA).
MAX14921
-Available in an 80-pin (12mm x 12mm) TQFP package.
-Pricing starts at $6.15 (1000-up, FOB USA).
Both devices operate over the -40°C to +85°C extended temperature range.