ISL6294A Datasheet, PDF (5/8 Pages) Intersil Corporation – High Input Voltage Charger

ISL6294A
VIN
PPR
POR
EN
GND
PRE
REG
V_{OS +}
V_REF
-
+
VCC
BAT
-
200k
CHARGE
CONTROL
EN
-
+
V_REF
VCC
-
DIE
TEMP
+
+115°C
BAT
CHG
IMIN
FIGURE 3. BLOCK DIAGRAM
IREF
TRICKLE
CC
4.2V
I_REF
2.55V
19%I_REF
CV
CHARGE
VOLTAGE
CHARGE
CURRENT
I_MIN
76%I _REF
CHG
CHG
INDICATION
FIGURE 4. TYPICAL CHARGE PROFILE
TIME
Description
The ISL6294A charges a Li-ion battery using a CC/CV
profile. The constant current I_REF is set with the external
resistor R_IREF (see Figure 1) and the constant voltage is
fixed at 4.2V. If the battery voltage is below a typical 2.55V
trickle-charge threshold, the ISL6294A charges the battery
with a trickle current of 19% of I_REF until the battery voltage
rises above the trickle charge threshold. Fast charge CC
mode is maintained at the rate determined by programming
I_REF until the cell voltage rises to 4.2V. When the battery
voltage reaches 4.2V, the charger enters a CV mode and
regulates the battery voltage at 4.2V to fully charge the
battery without the risk of over charge. Upon reaching an
end-of-charge (EOC) current, the charger indicates the
charge completion with the CHG pin, but the charger
continues to output the 4.2V voltage. Figure 4 shows the
typical charge waveforms after the power is on.
The EOC current level IMIN is programmable with the
external resistor R_IMIN (see Figure 1). The CHG signal turns
5
FN6821.2
December 11, 2008