SMB139 SUMMIT Microelectronics, Inc:, SMB139 Datasheet - Page 2

• Manufacturer Part Number: SMB139
• Description: ? Summit Microelectronics, Inc. 2005 ? 757 N. Mary Avenue ? Sunnyvale Ca 94085 ? Phone [phone] ? Fax [phone] Http //www.summitmicro.com/ 2121 3.0 6/19/2008 1 Programmable Linear Battery Charger
• Manufacturer: SUMMIT Microelectronics, Inc:

The SMB139 is a fully programmable, linear battery
charger for single-cell Li-Ion and Li-Polymer battery
packs. The device’s simple, linear-mode operation and
ultra-small package significantly reduce component
count and required board space. The SMB139 provides
four
conditioning (pre-charge), constant current and constant
voltage. The overall system accuracy of the SMB139 is
1%, allowing for a higher capacity utilization versus other
conventional solutions.
When a battery or an external supply is inserted and the
ENABLE input is asserted, the SMB139 performs the
pre-qualification checks before initiating a charging
cycle. The input voltage needs to be higher than the
UVLO threshold and the cell temperature needs to be
within the temperature limits for the charging cycle to
start.
SMB139 enters a shutdown mode, thereby saving
battery power. A programmable option also exists that
allows the user to prevent battery charging until an I
command has been issued.
If the battery voltage is below 2.0V (trickle-charge to pre-
charge threshold), the device will apply a trickle-charge
current of 3mA (typical). This allows the SMB139 to
reset the protection circuit in the battery pack and bring
the
compromising safety.
Once the battery voltage crosses the 2.0V threshold, the
SMB139 enters the pre-charge mode.
replenishes deeply depleted cells and minimizes heat
dissipation during the initial charge cycle.
preconditioning current is programmable, with the default
value at C/10. If the battery voltage does not reach the
preconditioning voltage level (programmable) within a
specified amount of time (pre-charge timeout), the safety
timer expires and the charge cycle is terminated.
When the battery voltage reaches the pre-charge to fast-
charge voltage level, the SMB139 enters the constant
current (fast charge) mode.
level is programmable via the corresponding register.
GENERAL DESCRIPTION
battery
main
Summit Microelectronics, Inc
As soon as the input supply is removed, the
charging
voltage
to
phases:
a
The fast charge current
higher
trickle-charge,
level
This mode
without
pre-
The
2121 3.0 6/19/2008
2
C
Once the final float voltage (programmable) has been
reached, the battery charger will enter a constant voltage
mode in which the battery voltage is kept constant,
allowing the charge current to gradually taper off. The
constant-voltage charging mode will continue until the
charge current drops below the termination current
threshold, or until the fast charge timer has expires. The
termination current threshold is programmable.
After the charge cycle has terminated, the SMB139
continues to monitor the battery voltage. If the battery
voltage falls below the recharge threshold (typically
125mV
automatically top-off the battery.
A wide range of protection features is also included in
the SMB139. These include input and output (battery)
over-voltage protection, battery missing detector and
thermal
monitoring and pre-qualification.
The following charging parameters can be adjusted
dynamically via the I2C interface, for optimizing battery
management real-time. These parameters can also be
programmed statically via a user-friendly GUI interface:
•
•
•
•
•
•
•
Battery (float) voltage
Fast charge current
Pre-conditioning voltage threshold
Pre-conditioning charge current
Termination current
Safety charge timers
Temperature window.
below
monitor
float
for
voltage),
continuous
Preliminary Information
the
cell
SMB139
SMB139
temperature
2
can