Smart battery sensor laptops battery status

Freescale Semiconductor's MM912J637 laptop battery sensor measures current, voltage and temperature of lead-acid batteries and deduces the status of the laptop battery from these parameters. Amidst increasing numbers of hybrid electric vehicles and start-stop IBM 40Y6799



systems (“mild hybrid”), it becomes increasingly important for car designers to determine the laptop battery status.

The MM912J637 combines an S12 microcontroller with an integrated analog control circuit in smartmos technology, significantly reducing the sony VGP-BPS9/S footprint for the application. According to Freescale, the MM912J637 is fully AEC-Q100 compliant and qualified for operating temperatures from -40 through +125 degrees Celsius.

The device communicates with ECUs through a LIN interface. It contains a 16-bit Delta-Sigma ADC with two channels for concurrent measurement of current and voltage. In addition it contains a third ADC for Sony VGP-BPS13AS

temperature measurements. Current is measured across a shunt resistor at the negative pole while voltage is measured at the positive pole of the Sony VGP-BPS21

laptop battery. Currents up to 2000 A can be measured at an accuracy of 5 mA.

Samples of the Sony VGP-BPS8

battery are available now, with volume production scheduled to ramp up in September 2011. Evaluation kits as well as software tools are also available.