Integrated, Precision Battery Sensor for Automotive Systems

The ADuCM342 is a fully integrated, 8 kHz data acquisition system that incorporates dual, high performance, multichannel, Σ-Δ analogto-digital converters (ADCs), a 32-bit ARM® Cortex™-M3 processor, and flash. The ADuCM342 has 128 kB Flash/EE memory and a 4 kB data flash. Error correction code (ECC) is available on all flash and SRAM memories.

The ADuCM342 is a complete system solution for battery monitoring in 12 V automotive applications.

The ADuCM342 integrates all features required to precisely and intelligently monitor, process, and diagnose 12 V battery parameters including battery current, voltage, and temperature over a wide range of operating conditions.

Minimizing external system components, the device is powered directly from a 12 V battery. On-chip, low dropout (LDO) regulators generate the supply voltage for two integrated Σ-Δ ADCs. The ADCs precisely measure the battery current, voltage, and temperature to characterize the state of the health and the charge of the car battery.

The device operates from an on-chip, 16.384 MHz high frequency oscillator that supplies the system clock that is routed through a programmable clock divider, from which the core clock operating frequency is generated. The device also contains a 32.768 kHz oscillator for low power operation.

The analog subsystem consists of an ADC with a programmable-gain amplifier (PGA) that allows the monitoring of various current and voltage ranges. The analog subsystem also includes an on-chip precision reference.

The ADuCM342 integrates a range of on‑chip peripherals that can be configured under core software control as required in the application. These peripherals include a serial port interface (SPI) serial input/output communication controller, six general-purpose input/output (GPIO) pins, one general-purpose timer, a wake-up timer, and a watchdog timer. For more information, refer to the ADuCM342 hardware reference manual.

The ADuCM342 is designed to operate in battery-powered applications where low power operation is critical. The microcontroller core can be configured in normal operating mode, which results in an overall system current consumption of 18.5 mA when all peripherals are active. The device can also be configured in a number of low power operating modes under direct program control, consuming <100 μA.

The ADuCM342 includes a local interconnect network (LIN) physical interface for single-wire, high voltage communications in automotive environments. The LIN transceiver is compliant to LIN 2.2A and society of automotive engineers (SAE) J2602-2.

The device operates from an external 3.6 V to 19 V (on VDD, Pin 26) voltage supply and is specified over the −40°C to +115°C temperature range, with additional typical specifications at +115°C to +125°C.

The information in this data sheet is relevant for silicon revision A60.

The ADuCM342 is developed for use in ISO 26262 applications for automotive safety integrity level capability C (ASIL C) supporting single-point fault metric (SPFM) 90% and latent fault metric (LFM) 60% at the IC component level.

The ADuCM342 is a low electromagnetic emissions and high electromagnetic immunity device.

APPLICATIONS

* Battery sensing and management for automotive and light mobility vehicles

* Auxiliary battery monitoring in xEV

* Lead acid battery measurement for power supplies in industrial and medical domains

* High precision ADCs

* Dual-channel, simultaneous sampling

* IADC 20-bit Σ-Δ (minimizes range switching)

* VADC/TADC 20-bit Σ-Δ

* Programmable ADC conversion rate from 4 Hz to 8 kHz

* On-chip ±5 ppm/°C voltage reference

* Current channel

* Fully differential, buffered input

* Programmable-gain (from 4 to 512)

* ADC absolute input range: −200 mV to +300 mV

* Digital comparator with current accumulator feature

* Voltage channel

* Buffered, on-chip attenuator for 12 V battery input

* Temperature channel

* External and on-chip temperature sensor options

* Microcontroller

* ARM Cortex-M3 32-bit processor

* 16.384 MHz precision oscillator with 1% accuracy (high precision)

* Serial wire debug (SWD) port supporting code download and debug

* Automotive qualified integrated LIN transceiver

* LIN 2.2A-compatible target, 100 kbaud fast download option

* SAE J2602-compatible target

* Low electromagnetic emissions

* High electromagnetic immunity