I²C battery monitor measures state of charge parameters

The LTC2944 multicell battery monitor from Linear Technology makes direct measurements of 3.6V to 60V battery stacks. Level shifting circuitry on the supply and measurement pins is not required to interface with multicell voltages, so total current consumption is minimised and measurement accuracy is preserved.

According to the company, the LTC2944 is a high voltage battery monitor that measures charge, voltage, current and temperature to 1% accuracy, which is necessary to assess battery state of charge.

The LTC2944 is suitable for multicell applications, including electric vehicles, ebikes, 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 analogue integrator accommodates either current polarity and a programmable prescaler supports a range of battery capacities.

The information is communicated to the host system over an I²C/SMBus-compatible 2-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, signals an alert using either the SMBus alert protocol or by setting a register flag.

The LTC2944 is offered in commercial and industrial versions, operating in temperatures ranging from 0 to 70°C and –40 to 85°C, respectively. The device is available in a RoHS-compliant, 8pin, 3 x 3mm DFN package.

Additional features:

•Internal 14bit A/D converter measures voltage, current and temperature

•±50mV sense voltage range

•Configurable alert output/charge complete input

•Less than 150μA quiescent current

Author
Peggy Lee