60V battery monitor measures state of charge with 1% accuracy

January 31, 2017 // By Nick Flaherty
Linear Technology has launched a multicell battery monitor that makes direct measurements of 3.6V to 60V battery stacks to an accuracy of 1%.

The LTC2944 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 state of charge (SoC).  No level shifting circuitry on the supply and measurement pins is required to interface with multicell voltages, so total current consumption is minimized with a quiescent current under 150μA while preserving the measurement accuracy.

The LTC2944 is aimed at 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 analogue 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 via a 14bit ADC 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. It is available today in a small RoHS-compliant, 8-pin 3mm x 3mm DFN package.Pricing starts at $2.85 each in 1,000-piece quantities.

A 14-Bit ADC measures Voltage, Current & Temperature

1% Charge, Voltage & Current Accuracy

±50mV Sense Voltage Range

High Side Sense

I²C/SMBus Interface

Configurable Alert Output/Charge Complete Input

 

Small 8-Pin 3mm x 3mm DFN package