Batteries and Portable Power

Linear Tech Releases High Voltage Battery Stack Monitor To Support Hybrid/Electric Vehicles & Battery Backup Systems

Linear Technology announced the LTC6802, a highly integrated multicell battery monitoring IC capable of measuring up to 12 individual battery cells. The device’s proprietary design allows multiple LTC6802s to be stacked in series without optocouplers or isolators, for precision voltage monitoring of every cell in long strings of series-connected batteries. Long battery strings enable high power, rechargeable applications, such as electric and hybrid electric vehicles, scooters, motorcycles, golf carts, wheelchairs, boats, forklifts, robotics, portable medical equipment, and uninterruptible power supply (UPS) systems.

With superior energy density, Lithium-Ion batteries are poised to be the power source of choice for these applications. However, designing a large, highly reliable and long-lasting Li-Ion battery stack is a very complex problem. Li-Ion cells are sensitive to overcharging or over-discharging, requiring that each cell in a stack is carefully managed. The LTC6802 is said to make this possible with quick and accurate measurements of all cell voltages, even in the presence of stack voltages over 1000V.

The maximum total measurement error is guaranteed at less than 0.25% from -40 to 85°C and all cell voltages in a battery stack can be measured within 13ms. Each cell is monitored for undervoltage and overvoltage conditions, and an associated MOSFET switch is available to discharge overcharged cells. Each LTC6802 communicates via a 1MHz serial interface, and includes temperature sensor inputs, GPIO lines and a precision voltage reference.

The LTC6802 was designed for the environmental and reliability challenges of automotive and industrial applications. It is fully specified for operation from -40 to 85°C and offers diagnostics and fault detection. The LTC6802 is a small 8 x 12mm surface mount device.

"The LTC6802 provides a precision analog interface for high performance battery stacks,”" stated Mike Kultgen, Design Manager for Linear Technology. "By handling the data acquisition task, the LTC6802 enables designers to implement state-of-the-art battery management techniques."

Priced at $9.95 each in 1,000-piece quantities, samples, demonstration boards and the data sheet are now available. The product will be available in production quantities in the fourth calendar quarter 2008.

Linear Technology Corp.
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