MIC79110 Datasheet, PDF (9/12 Pages) Micrel Semiconductor – Simple 1.2A Linear Li-Ion Battery Charger

MIC79110
capacity. An increase in the charge current during stage 1
does not shorten the total charge time. It will only shorten the
time for stage 1 to complete and lengthen the time in stage 2.
The lithium-ion loses charge due to aging whether it is used
or not. Do not store the batteries at full charge and high heat
because it will accelerate the aging process. Try and store
with 40% charge and in a cool environment.
Lithium-Ion Safety Precautions
Every lithium ion battery pack should have a safety board
which monitors the charge and discharge of the pack and
prevents dangerous occurrences. The specifications of these
safety boards are dictated by the cell manufacturer and may
include the following:
• Reverse polarity protection
• Charge temperature must not be charged when
temperature is lower than 0°C or above 45°C.
Micrel
• Charge current must not be too high, typically
below 0.7C
• Discharge current protection to prevent damage
due to short circuits.
• Protection circuitry for over voltage applied to the
battery terminals.
• Overcharge protection circuitry to stop charge
when the voltage per cell rises above 4.3V.
• Over discharge protection circuitry to stop dis-
charge when the battery voltage falls below 2.3V
(varies with manufacturer).
• Thermal shutdown protection for the battery if the
ambient temperature is above 100°C.
Start Charging
Lithium-Ion
Battery
Standby Mode
Do not charge
1
Shutdown
Pin
0
Deoc Flag is High
Stop Charge
Charging
Monitor Ibat
Deoc Flag is Low
Continue Charge
Stop Charge
Current Limit
Irset
Ibat
Stop Charge
End of Charge
<Ieoc
Ieoc<Ibat<Irset
Battery
Charging
<4.3V
>4.3V
>125C
Battery Voltage
Die
Temperature
<125C
July 2004
9
M9999-072004