Battery monitor measures state of charge parameters with high accuracy

Linear Technology has introduced the LTC2944 multicell battery monitor, which makes direct measurements of 3.6V to 60V battery stacks. Absolutely no level shifting circuitry on the supply and measurement pins is required to interface with multicell voltages, so total current consumption is minimized and measurement accuracy is preserved. The device is a true high voltage battery monitor that measures charge, voltage, current and temperature to 1% accuracy, the essential parameters required to accurately assess battery SoC. The device is ideal for multicell applications, including electric vehicles, ebikes/motorcycles/scooters, wheelchairs, golf carts and battery backup systems. Battery current is measured by monitoring the voltage across an external, high side sense resistor and integrating this information to infer charge. A bidirectional analog integrator accommodates either current polarity (battery charge or discharge), and a programmable prescaler supports a wide range of battery capacities. Charge, voltage, current and temperature information are communicated to the host system over an I²C/SMBus-compatible two-wire interface that is also used to configure the battery monitor. The host can program high and low thresholds for all measured parameters, which if tripped, signal an alert using either the SMBus alert protocol or by setting a register flag. The device is offered in commercial and industrial versions, supporting operating temperature ranges from 0C to 70C and –40C to 85C, respectively. It is available now in a small RoHS-compliant, eight-pin 3mm x 3mm DFN package.