I²C battery monitor measures state of charge parameters
Able to make direct measurements of 3.6 to 60V battery stacks, the LTC2944 multi-cell battery monitor has been released by Linear Technology. There is no level shifting circuitry on the supply and no measurement pins are required to interface with multi-cell voltages. This minimises current consumption and preserves measurement accuracy, says the company.
The LTC2944 is a true high voltage battery monitor that measures charge, voltage, current and temperature to one per cent accuracy, the essential parameters required to accurately assess battery state of charge.
Battery current is measured by monitoring the voltage across an external, high side sense resistor and integrating this information to infer charge. A bi-directional analogue integrator accommodates either current polarity (battery charge or discharge). A programmable pre-scaler supports a 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.
Suitable applications for the LTC2944 are electric vehicles, ebikes, motorcycles, scooters, wheelchairs, golf carts and battery back-up systems.
The monitor is offered in commercial and industrial versions, supporting 0 to 70 and –40 to +85 degree C operating ranges, respectively. It is available in a RoHS-compliant, eight-pin 3.0 x 3.0mm DFN package.
