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CAN-based sensor for automotive battery monitoring

Freescale Semiconductor (USA) introduced the MM9Z1J638 Xtrinsic CAN-based sensor for automotive battery voltage, current and temperature monitoring and battery states calculation. It is dedicated for lead-acid and lithium-ion batteries and is scheduled to be broadly available by the second half of 2013.

THE SENSOR INTEGRATES AN S12Z MICRO-CONTROLLER (MCU) and a Smartmos analog control integrated circuit. It operates at temperatures from -40 °C to +125 °C (AEC-Q100 automotive qualification) and comes in a 7-mm x 7-mm QFN package. The 50-Mhz MCU features a 32-bit ALU, 128 KiB Flash, 8 KiB RAM, and a 4 KiB EEPROM. The device includes a two-channel, 16-bit analog to digital converter (ADC) for simultaneous measurement of voltage and current and a 16-bit ADC for temperature measurement.
The sensor may communicate measured parameters at intervals or on request from the in-vehicle network via either the CAN (requires an external PHY) or LIN protocols. Four dedicated voltage inputs cover 10-V, 16-V, 28-V, and 52-V measurement ranges. Current measurement range is up to ±2000 A with an accuracy of 5 mA and a resolution of 1 mA. The on-chip temperature sensor provides accuracy of ±2 °C (-20 °C to +60 °C) and ±3 °C (-40 °C to +125 °C). The sensor supports normal and low-power modes. An msCAN protocol controller with TxD and RxD terminals and bus wake-up detection is available. Integrated 5-V regulator supplies MCU, CAN PHY and other external components.
Precise knowledge of the battery’s state of health (SOH), state of charge (SOC) and state of function (SOF) can provide early detection of impending failure, the leading cause of vehicle breakdowns due to the electrical system. In addition, the power consumption of the battery sensor itself must be as low as possible to ensure energy efficiency. “Devices such as the intelligent battery sensor are becoming necessary as electronic content and start-stop systems in automobiles continue to increase in quantity and importance,” said Gavin Woods, vice president and general manager of Freescale’s Analog & Mixed-Signal Products Division. “We are providing the industry’s first CAN-based, automotive-qualified and cost-effective solution that enables precise monitoring of critical battery parameters.”
The company is a provider of embedded processing solutions, for the automotive, consumer, industrial and networking markets from microprocessors and micro-controllers to sensors, analog integrated circuits and connectivity.

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