Electric vehicles require very precise measurements of the state of charge (SoC) and state of health (SoH) of the traction battery to accurately estimate the vehicle’s range. Ams OSRAM has offered power management ICs and sensor interfaces for many novel applications, from mobile devices, wearables, smart home, building automation, digital healthcare to high-precision battery sensor interfaces for EVs (Electric Vehicles). The high-precision battery management systems help reduce power loss, stretch travel range, and preserve environment.
Ams Osram’s shunt resistor-based zero-offset battery sensing solution supports automotive battery management systems, enabling very accurate measurements of the current and voltage required in this application. To understand how Ams OSRAM battery sensor interfaces work, we illustrate the data acquisition IC AS8510 for battery management and the companion IC AS8525 for current measurement.
Ams OSRAM’s AS8510 can be considered offset free with low noise. The device is capable of measuring the battery current from mA range up to kA range using a 100 µOhm shunt resistor mounted on the positive pole of the battery. AS8510 has two channels with the first being dedicated to the battery current measurement, and the second being used for either the battery voltage synchronized with the current or an analog output from an internal or external temperature sensor. The result of analog signal acquisition is accessible via the 4-wire standard SPI interface after it’s converted by two 16-bit high resolution Sigma-Delta ADC and digitally filtered.
AS8525 is a LIN-bus transceiver with voltage regulators, programmable gain high side amplifier with voltage attenuator. This device is a companion IC for automotive battery sensor systems for both low-side and high-side current sensing applications. AS8525 provides 2 regulated 3.3V supplies from the battery supply, a voltage attenuator by a high-precision resistive network that can be enabled or disabled through SPI and a LIN bus interface.
The typical application of automotive battery management system is shown below: