Linear Technology has introduced 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.
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 remains a complex problem. Li-ion cells can be sensitive to overcharging or over-discharging, requiring that each cell in a stack is carefully managed. The LTC6802 makes this possible with quick and accurate measurements of all cell voltages, even in the presence of stack voltages of more than 1,000V.
The maximum total measurement error is guaranteed at less than 0.25% from -40°C to 85°C and all cell voltages in a battery stack can be measured within 13 ms. 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°C to 85°C and offers diagnostics and fault detection. The LTC6802 is a small 8mm x 12mm surface mount device. The combined robustness, exceptional precision and tiny package directly address the critical requirements of emerging and advanced battery technologies.