This adds a new challenge to the designers who were not used to isolation in the conventional vehicles. This document provides various options to isolate the ADC’s in battery monitoring circuits.
Typical monitoring circuits consist of a shunt resistor in series with the system load. The voltage drop across this shunt resistor in indicative of the load current. The signal from the shunt resistor gets amplified and converted to digital signal before being fed to the microcontroller (MCU). Since the MCU is on the low voltage side while the measurement circuitry comprising of the amplifier and the ADC is on the high voltage side, an isolation devices sits between these two circuits. The type of isolator to be used depends on the interface used to communicate between the ADC and the MCU.
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