Linear Technology Corp. has introduced the LTC2944 multicell battery monitor, which makes direct measurements of 3.6 V to 60 V 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 LTC2944 is a true high voltage battery monitor that measures charge, voltage, current and temperature to 1 percent accuracy, the essential parameters required to accurately assess battery state of charge (SoC).
The LTC2944 is well suited 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 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, signal an alert using either the SMBus alert protocol or by setting a register flag.
The LTC2944 is offered in commercial and industrial versions, supporting operating temperature ranges from 0°C to 70°C and –40°C to 85°C, respectively. The LTC2944 is available today in a small RoHS-compliant, 8-pin 3 mm by 3 mm DFN package. Pricing starts at $2.85 each in 1,000-piece quantities.
