Current measurement techniques to compensate for shunt drift

Abstract

The disclosure relates to current measurement techniques to compensate for shunt drift. Described are various current measurement techniques that can compensate for drift in shunt resistance. Determining a resistance of a shunt resistor, e.g., coupled to a battery terminal, can include introducing a known signal in sync with the chop phases of a dual system chop scheme, chopping the known signal out in the main signal path, and explicitly extracting the known signal in a parallel, additional signal deprocessing path.

Description

technical field [0001] The present disclosure relates to current measurement devices and methods. Background technique [0002] In a shunt-based current measurement setup, current is measured by placing a known low-resistance "shunt" in series with the current to be measured, and then measuring the voltage across the series shunt. Application of Ohm's law (current (I) = voltage (V) / resistance (R)) will result in a current flowing through the shunt. The accuracy of the current measurement depends on the accuracy of the voltage measurement and the resistance accuracy of the shunt itself. [0003] Typically, the system is calibrated at the factory, which can include temperature compensation at multiple temperature points to compensate for the temperature effect of the shunt. For automotive applications, a single temperature calibration is typically used. However, over the lifetime of a shunt, its value can change independently of temperature, which can be unpredictable. Add...

AI Technical Summary

Problems solved by technology

However, over the lifetime of a shunt, its value can change independently of temperature, which can be unpredictable

Also, in typical applications, the current through the shunt is continuously monitored, which can present challenges in monitoring the shunt itself

This shunt typically has a resistance of less than 1 ohm, which can add further challenges

Images