IC for hybrids
04 May 2010
Battery management data acquisition front-end IC features highest accuracy available.
Austriamicrosystems’ AS8510 is a high precision data acquisition front-end IC for automotive battery current, voltage, temperature sense applications. It features unique zero offset for simultaneous voltage, current and temperature measurement in conventional, hybrid or electric vehicles. It can also be used for sensor interface applications where the precise measurement of small signals close to ground is required.
The flexible sensor interface IC offers advantages over alternative solutions, including being the first to feature a 16bit dual-channel ADC + PGA architecture with less than one LSB of offset and noise.
The data acquisition front-end IC features two independent analogue input channels with 16bit ADCs, each with individually programmable sampling rates. Each channel has a low-drift programmable gain amplifier for handling +/- 160 mV signals or 0V to 1V when bypassing PGA. A highly linear sigma delta architecture and wide range of sampling rates allows the AS8510 to provide flexible support of EV (electric vehicle) applications. The offset auto-zero feature (both channels) allows high accuracy measurements with low value shunt resistance with negligible insertion loss. Also, various operating modes include low power standby with current monitoring for active wake-up.
"The need for increasingly more accurate and efficient power management is being driven by the exploding market for battery powered devices and, increasingly, electric vehicles," stated Manfred Brandl, Product Manager Automotive Sensor Interface and SBC ASSPs at austriamicrosystems. "With the AS8510, designers have the highest accuracy available and the flexibility required for a wide variety of applications. In addition, by adding an austriamicrosystems LIN companion IC and a low-cost microcontroller, automotive applications can realise reduced time to market in an evolving field at competitive price and improved performance."
The AS8510 operates with the current shunt sensor in a 12V system either at a battery's ground terminal or at the plus terminal in conjunction with dedicated level shift companion IC, or it can be used as a general purpose sensor interface for precise measurement of signals close to ground. Fully differential inputs allow the AS8510 to capture differential signals with 300mV of common mode above ground and 160mV below ground. The two-channel architecture enables digital error correction techniques like delta by sigma division or capture of bridge current / voltages with subsequent error correction in an external microcontroller. In addition, the AS8510 draws just 40µA in standby mode.
It can be configured for differential simultaneous two-channel operation, or for multiplexing two single-ended channels in addition to one of the differential channels for sequential measurements. Furthermore, for measuring voltage and current, the AS8510 allows accurate temperature measurement from either the internal sensor or from an external temperature sensor, which may be powered by an on-chip 250µA current source. It includes an internal precision reference, integrated digital low-pass filters, on-chip precision oscillators and a four-wire SPI interface.
The AS8510 is available in a SSOP20 package, operates from 3.3 volts, and has an ambient operating temperature range of
-40°C to +125°C.
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