Sendyne module precisely measures DC current from 3 mA to 500 A over the automotive temperature range
22 August 2013
Sendyne has introduced the SFP100EVB, a turnkey module for precision measurement of current, voltage and temperature. The module was created for applications where accurate current measurements under conditions of widely-changing temperature are essential, such as battery monitoring for industrial, automotive, grid and off-grid storage, as well as photovoltaic arrays, drive controls, and precision current flow measurements (including battery cells characterizations).
Operating in the automotive temperature range of -40 °C to +125 °C, the module simultaneously measures bi-directional DC current through a 100 micro-Ohm resistive shunt, voltage and temperature at 4 points.
The module is capable of resolving currents from 3 mA to 513 A within a single continuous measurement range (without sub-ranging or gain switching), with uniform resolution of 61 µA, and performs automatic charge accumulation for built-in precision Coulomb counting.
The SFP100EVB implements several of Sendyne’s patented and patent pending technologies in order to achieve precision current measurements for field use comparable to the precision of metrology grade lab instruments.
From +10 °C to +50 °C, the module typically achieves an accuracy of ±0.05 % for both current and voltage measurements; at the extremes of the full operating temperature range, the module achieves an accuracy of ± 0.4 % for current measurement and ± 0.6 % for voltage measurement. Accuracy is defined as the cumulative effect of all possible sources of error, including offset, gain and stability of the built-in precision voltage reference.
The precision of the accumulated charge quantity in the Coulomb count register is higher than would be possible by reading and accumulating individual current measurements, due to a precisely uniform sampling rate and absence of jitter. Moreover, if full-scale (positive or negative) current measurements are accumulated continuously, the Coulomb count register is capable of collecting up-to 43 years of data without over- or under-flow.
The module utilizes Sendyne’s SFP100 measurement IC that contains two 24-bit ΣΔ ADCs. Galvanic isolation allows both low-side and high-side current measurements and provides improved attenuation of system-induced noise. Power consumption is typically 82mW. The SFP100EVB communicates internally digitized values to the host through a simple, LIN-like serial interface; custom interfaces can be accommodated.