Battery stack fault monitor operates without microprocessor

The LTC6801 has been designed to monitor up to 12 series connected battery cells for overvoltage and undervoltage conditions. According to Linear, multiple LTC6801 devices can be daisy chained, providing a method to monitor each individual cell in very long battery strings. When connected in a daisy chain, a single differential clock output confirms that all cells in the stack are within the defined operating range. The clock interface is said to provide high noise immunity and ensure that fault conditions are not hidden by frozen bits or short circuit conditions. The result, says Linear, is a simple design that can serve as a complete monitoring or redundant circuit. The LTC6801 is a low cost companion to the LTC6802 precision battery measurement and cell balancing ic, providing a backup circuit for hybrid electric battery packs, battery backup systems, and other high powered Li-Ion battery systems. It is specified for operation from -40 to 85^°C and two temperature sensor inputs are monitored for over temperature faults. Mike Kultgen, design manager for Linear Technology, said: "The LTC6801 incorporates a number of important reliability features, including a comprehensive self test to guarantee accuracy. These features will prove invaluable for high reliability battery management systems." The product will be available in production quantities in early 2010.