MIC79110 Micrel Semiconductor, MIC79110 Datasheet - Page 10

• Manufacturer Part Number: MIC79110
• Description: Simple 1.2A Linear Li-Ion Battery Charger
• Manufacturer: Micrel Semiconductor

MIC79110
Simple Charger - External Trigger to Reset Charge
Cycle reset
The V
When Vin is below Vbat, the Ibat current is near zero and the
reverse shutoff circuit is turning the charge to the battery off.
The I
pulled low when the Ibat current is above the Ieoc current set
by R
forced low and helps discharge C
the set voltage, the Ibat begins to slowly drop. When the Ibat
is less than the I
impedance, indicating end-of-charge. When an external sig-
nal is applied to the gate, the external N
DEOC pins to ground. This restarts the charging process.
M9999-072004
Reset charge cycle.
EOC
BAT
IN
. When the D
voltage steps up to a voltage greater than V
slowly increases as V
200Ω
EOC
threshold, the D
EOC
SD
RSET
VSENSE
VBAT
VIN
is low, the shutdown pin is also
IN
4
9
SD
REOC
DEOC
ACHG
rises above V
1
GND
7
VIN
Vgate
. When the V
EOC
8
CH
2
5
10
Active high DEOC pin
VSD
output goes high
pulls the SD and
Active low DEOC pin
1MΩ
Ibattery
BAT
BAT
C
0.1µF
DELAY
. D
reaches
2kΩ
EOC
BAT
is
3
.
10
6
Vbat set voltage
SD threshold
9
External Trigger to Reset Charge Cycle Reset
Vbat
1 - V
2 - SD held low by C
3 - Deoc releases SD, resistor pull-up from SD pin'vo
4 - An external signal applied to the gate of the
5 - Ibattery is near zero (2 to 4µA) because V
6 - I
7 - External N
8 - Active high DEOC pin goes high because of
9 - I
10 - Active low D
11 - Legitimate Activation of active low D
shutdown low.
V
external N
below V
ing the charge to the battery off.
voltage. I
and D
turns on.
reverse shutoff. D
ceeds D
V
off. As V
voltage shutoff turns off, D
comes active. While I
D
D
shuts down part and D
high.
BAT
BAT
IN
BAT
EOC
EOC
IN
pulls V
steps up to a voltage greater than V
2
is decreased as V
decreases below (see #5) D
and reverse shutoff holds D
Vin
EOC
threshold I
active low goes low, when I
BAT
EOC
BAT
IN
is released high allowing V
CH
CH
SD
and the reverse shutoff circuit is turn-
increases above V
decreases below the D
threshold, then goes low.
pulls SD pin-to-ground.
turns part on, after a small delay I
to V
EOC
BAT
IN
EOC
SD
.
is high because V
goes high.
BAT
until active high D
remains high until I
EOC
BAT
is below D
approaches V
AL (active low) goes
EOC
BAT
EOC
comparator be-
EOC
EOC
EOC
, the reverse
BAT
SD
EOC
comparator
IN
threshold.
to go high
EOC
threshold
threshold
exceeds
BAT
is below
until SD
BAT
BAT
July 2004
.
pulls
IN
BAT
ex-
set
Micrel
is