Analog Devices - Integrated Lithium-Ion Battery Protection Circuit And Safety Monitor

Analog Devices has addressed the requirements of Li-ion battery manufacturers and power system designers with the unveiling today of a Li-ion battery monitoring and protection system that integrates all necessary components, including voltage and current measurement, signal isolation and safety monitoring.

Compared to NiMH (nickel-metal hydride) batteries, Li-ion batteries have a better energy-to-weight ratio, offer more efficient storage capacity over multiple charge-discharge cycles, and suffer less charge leakage when not in use. And unlike NiMH batteries traditionally used in high-voltage applications, battery stacks using Li-ion technology can comprise a large number of individual cells totalling hundreds of volts. Each cell must be properly monitored and balanced to ensure user safety, improve battery performance and extend battery life. ADI’s new Li-ion battery monitoring and protection system performs these functions while also allowing power system designers to replace costly discrete components, decrease power consumption and reduce system space.

“Li-ion batteries must be treated with respect. Fires have occurred in notebook computer applications because over-voltage peaks were not monitored correctly,” said Steve Sockolov, director, Precision Signal Processing group, Analog Devices. “Although the quality of battery fabrication has improved, guarding against higher temperature conditions in any energy, industrial or automotive application is critical. As one of the top suppliers to the energy, industrial and automotive industries, Analog Devices has the systems expertise and the right components to help customers with the design challenges associated with battery monitoring and safety.”

ADI offers the main components required for a complete Li-ion battery monitoring and protection system:

* Voltage measurement device - monitors and balances the cells (AD7280)
* Current measurement device - monitors the cell stack’s current (ADuC703x or AD821x)
* Isolator - brings the measurement signals across the high-voltage barrier to the battery management unit (ADuM140x or ADuM540x)
* Safety monitor - enables creation of a fail-safe circuit and safe environment to the user (AD8280)
* Battery management unit – controls and manages battery functions to optimize operation (Blackfin ADSP-50x