Global Sources
EE Times-Asia
Stay in touch with EE Times Asia
EE Times-Asia > Power/Alternative Energy
Power/Alternative Energy??

Battery manager ensures safety, efficiency

Posted: 12 Oct 2009 ?? ?Print Version ?Bookmark and Share

Keywords:battery management? automotive? Li-ion? power supply?

ATA6870/71 battery manager

Atmel Corp. ensures the safety and efficiency of high-cell count Li-ion battery packs with a new two-chip solution. Such battery packs are used for automotive and industrial applications including electrical/hybrid vehicles, e-bikes or uninterruptible power supplies.

The ATA6870/71 chipset requires less external components than comparable solutions because it includes a hot plug-in capability, six integrated ADCs with a cut-off frequency lower than 30Hz, saving external filters, and a stackable MCU power supply. With Atmel's cost-efficient 30V CMOS technology, these features allow cost savings of up to 60 percent, compared to existing solutions.

The ATA6870 is the industry's first battery management IC to include all functionalities required to control a high-cell-count Li-ion battery including six precise 12bit ADCs for voltage monitoring, cell balancing, cell temperature measuring, and unique features such as stackable integrated power supply for a MCU or hot plug-in capability.

"Battery safety and efficiency are key for industrial and automotive battery applications," said Claus Mochel, automotive high-voltage marketing manager for Atmel. "Atmel's new ATA6870 and ATA6871 address these issues by offering a battery management solution with an unsurpassed safety concept and advanced parallel cell voltage measuring and balancing technique."

Since Li-ion batteries are very sensitive against overcharging and deep discharge, they may burn or explode. To prevent this, Atmel provides a special safety strategy with its secondary protection device, the ATA6871. This monitors the battery cells' voltage and temperature, and prevents Li-ion batteries from thermal runaway or exploding. If either of these were to occur in a battery cell, it can then be switched off by the emergency relays. With its implemented self-test routines, which run without an external MCU or software and its hardware-implemented monitoring thresholds, the ATA6871 constitutes the highest available safety level for Li-ion battery monitoring. Proper operation is ensured even if the primary device is damaged.

Both the ATA6870 and the ATA6871 circuits monitor six-battery cells and can be stacked up to 16x. For the highest communication robustness between the stacked ICs, the ICs feature level shifters based on current sources. The ATA6870 also includes an 8bit checksum monitor that helps further increase data communication robustness.

The ATA6870 provides a dedicated ADC for each battery cell to be monitored. This enables simultaneous measurement voltage of all cells within one battery string for precise state-of-charge determination of Li-ion battery cells.

The integrated power supply for the MCU can be stacked the same way as the IC itself. Therefore, the current required to supply the MCU can be taken from the top cell and be fed back into the battery string's bottom cell. As a result, the MCU's current consumption will not cause any cell imbalance, helping designers save expensive high-voltage devices.

Samples of the new ATA6870 and ATA6871 ICs are now available in small QFN48/SSO28 packages. Pricing starts at $2.95 for the ATA6870 and $1.31 for the ATA6871 at 10k-piece quantities. The evaluation kits are also available now. This enables a quick start with the ICs to allow prototyping and testing of new battery designs immediately. For the ATA6870, Atmel offers additional software for PCs and laptops with a GUI to control and optimize high-cell-count battery stacks.

Article Comments - Battery manager ensures safety, effi...
*? You can enter [0] more charecters.
*Verify code:


Visit Asia Webinars to learn about the latest in technology and get practical design tips.

Back to Top