Smart Battery Monitoring
Fri, 02/25/2005 - 7:51am
Atmel announces the ATmega406, a high-voltage technology AVR microcontroller implementing full 2 to 4 cell Lithium Ion smart battery monitoring and protection on a single chip. To enable the ATmega406 to be powered directly from a 2-, 3- or 4-cell Li-ion configuration, the device includes an on-chip voltage regulator allowing the device to be powered from 4 to 25 V. It also features three 25 V-tolerant FET drivers for charge, discharge, and pre-charge, as well as on-chip FETs for cell balancing. The device has a Coulomb Counter ADC with an 18-bit output for battery current monitoring as well as a 12-bit ADC for individual cell voltage and temperature monitoring. Battery protection is implemented as independent circuitry, not requiring the MCU to operate. If the device is exposed to an over-current or short-circuit condition, the autonomous battery protection will shut off the affected FET. Likewise, if any cell voltage drops to a potentially damaging voltage level, ATmega406 will automatically prevent further battery discharge by shutting down the discharge FET and going to a power-off mode.