ISL6294_14 Datasheet, PDF (5/9 Pages) Intersil Corporation – High Input Voltage Charger

ISL6294
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 ISL6294 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 ISL6294 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 I_MIN is programmable with the
external resistor R_IMIN (See Figure 1). The CHG signal turns
5
FN9174.4
July 9, 2007