New Product News
SMART BATTERY
MONITOR
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Atmel® Corporation introduces
the ATmega406, its first high-voltage technology AVR®
microcontroller implementing full two- to four-cell Lithium Ion smart battery monitoring and protection on a single
chip. Lithium Ion (Li-ion) is the battery chemistry of choice for high-end portable applications such as
laptop PCs, cell phones, and digital
cameras, due to its high-energy-per-weight-and-volume ratio, combined
with a high-load current.
To enable the ATmega406 to be
powered directly from a two-, three-,
or four-cell Li-ion configuration, the
device includes an on-chip voltage
regulator allowing the device to be
powered from four to 25 volts. It also
features three 25-volt-tolerant FET
drivers for charge, discharge, and
pre-charge, as well as on-chip FETs
for cell balancing.
To provide the most accurate
estimate of charge left, 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. Both
ADCs use high-accuracy on-chip
voltage reference. Battery protection
is autonomous, providing the end-user with the best safety, as MCU-related issues such as a code
runaway or a software bug do
not affect it. Adding communication
periphery and an efficient MCU
architecture, ATmega406 is the
first fully configurable single-chip
smart battery solution on the
market.
NUTS & VOLTS
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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
60
the discharge FET and going to a
power-off mode.
A reliable estimate of charge
left can be used to extend battery
life by allowing the battery to use all
its power. The ATmega406’s
Coulomb Counter and Voltage ADC
are custom-made for optimal
current and voltage tracking,
essential for an accurate and
reliable estimate of charge left. The
current resolution of the Coulomb
Counter over the recommended
five-megohm sense resistor is 0.67
mA, allowing measurements of
more than ±30A. Both ADCs
benefit from a very accurate
internal voltage reference, with less
than ±0.1 percent error over
temperature after calibration.
With 40 KB of Flash program
memory, 512 bytes of EEPROM for
data parameter storage, and two
Kbytes of internal SRAM for
program data, ATmega406 packs
the algorithm processing power
necessary to implement battery
monitoring and management for a
full four-cell laptop PC battery pack
configuration. The device includes the
SM-bus interface for communication
with the host application, and Atmel’s
self-programming Flash allows
battery firmware upgrading through
this or any other interface, providing
the most flexible design solution on
the market.
All parts of the ATmega406 are
optimized for extremely low power
consumption, drawing less than 1.2
mA in active mode and less than
two uA in power-off mode.
A full suite of development tools
supports ATmega406, including the
JTAGICE mkII emulator, and a
smart battery development kit. The
ATmega406 is available in LQFP 48-
pin packages and pricing starts at
$2.75 for volumes above 100K.
For more information, contact:
ATMEL CORPORATION
Tel (408) 441-0311
Email: hmao@atmel.com
Web: www.atmet.com
Circle #51 on the Reader Service Card.
The Pocket Programmer Only $149.95
The portable programmer that uses the
printer port instead of a internal card,
with easy to use Windows software that
programs E(E)prom, Flash & Dallas Ram.
Intronics, Inc. • Tel. (913) 422-2094
Box 12723 / 612 Newton / Edwardsville, KS 66111
Add $8.00 COD
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