Analog Devices Offers Automotive Battery Monitoring with Highly Integrated Mixed-Signal IC
Analog Devices, Inc. announced a technology development that it claims significantly reduces automotive system failures resulting from faulty or discharged batteries. Designed to precisely measure battery voltage, current and temperature, the new ADuC703x family determines the battery's state-of-charge (SOC) and state-of-health (SOH) and uses this data to control battery charging and discharging profiles. As a result, it is claimed that the ADuC703x family ensures longer battery life and better dependability, while providing priority to critical automotive functions.
Powered directly from the car battery, and conveniently located on the negative battery pole to provide significant cost and space savings, the single-chip ADuC703x simplifies battery monitoring system design by integrating a number of components, including analog-to-digital converters (ADCs); a microcontroller; a local interconnect network (LIN) transceiver; embedded flash memory; an on-chip PGA (programmable gain amplifier) that provides a wide range of current measurements; on-chip attenuation resistors for direct battery voltage measurement and external or on-chip temperature sensing. The result is a precision battery monitor that offers a cost-efficient, smaller and simpler design alternative to discrete implementations consisting of a standalone processor, LIN transceiver, low drop-out regulator (LDO) and analog front end (AFE).
The ADuC703x family provides accurate, continuous measurement of battery state, even while the engine is off, while consuming as little as 300(mu)A in low-power mode and less than 10mA at 10MHz in normal operating mode. The devices' 16-bit sigma-delta ADCs measure battery voltage (direct connection, no external attenuation required) in the range of 3.5 to 18V and battery current from less than 1mA to 1500A. Combined with an on-chip PGA and a temperature sensor input, the ADuC703x allows the system integrator to determine the battery's SOC and SOH using a proprietary algorithm that resides in the monitor chip's flash memory. The information is then communicated via the on-chip LIN 2.0 (slave) compliant transceiver to the ECU (electronic control unit).
The new battery monitor family includes a dual-ADC version (ADuC7030/ ADuC7033) that monitors voltage and temperature in series and a version equipped with three ADCs (ADuC7032) that allows simultaneous voltage and temperature monitoring. All of the ADCs have an 8kHz maximum conversion rate. The current-measuring ADC has a fully differential buffered input, the ability to independently monitor battery current in power-down mode and noise performance of 60nV rms at low conversion rates. An on-chip FIFO (ADuC7032 only) can store multiple voltage and current conversions when the core is busy.
The processing engine at the core of the ADuC703x series is an ARM7TDMI with a core clock rate that is programmable to a maximum of 20MHz. The parts can be programmed (in-circuit) via a JTAG (Joint Test Action Group) or LIN interface, with flash storage retention of 20 years at 85°C. The new devices support a maximum power supply of 33V with all specifications applying over the range of 3.5 to 18V.
All devices in the ADuC703x family are sampling now with full production scheduled for November 2006. The operating temperature range is -40 to +125°C with all specifications applicable up to +115°C.
