Current shunt monitors enable high-precision voltage sensing in EVs

Diodes Incorporated has introduced a series of high-precision current shunt monitors developed to measure small sense voltages across a wide common-mode voltage range in EVs: the ZXCT21xQ family. Automotive applications for these single-stage instrumentation amplifiers comprise current sensing of load/rail currents in BLDC motor controllers, e-compressors, high-power DC-DC converters, OBC, BMS, ADAS power supplies, and wireless phone chargers.

Low offset voltage (±30μV) and gain error (±0.5% and ±0.8%) of the zero-drift core (typical ±100nV/°C) in these devices allow current sensing across the shunt, with maximum voltage drops as low as 10mV (full-scale). This enables small-value sense resistors to be utilised in high-accuracy monitoring of large-magnitude currents while decreasing the power lost during measurement. Also, the low quiescent current consumption of 100μA (maximum) helps to minimise power consumption.

These current monitors have a 0-26V rail-to-rail common-mode sense voltage range (irrespective of supply voltage), allowing high-side and low-side precision current measurement, while its REF pin allows bi-directional current flow measurement. The family has six voltage gain options (50V/V, 75V/V, 100V/V, 200V/V, 500V/V, and 1000V/V), each with its own unique order number with three accuracy variants.

All devices in the series are AEC-Q100 Grade 1 qualified, manufactured in IATF 16949 certified facilities, and support PPAP documentation.