ISL9220IRTZ-T Intersil, ISL9220IRTZ-T Datasheet - Page 9

• Manufacturer Part Number: ISL9220IRTZ-T
• Description: IC BATT CHRGR LIION 1CELL 20TQFN
• Manufacturer: Intersil

Specifications of ISL9220IRTZ-T

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion), Lithium-Polymer (Li-Pol)
• Voltage - Supply: 4.5 V ~ 14 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: *
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Theory of Operation
The ISL9220, ISL9220A is an integrated charger
optimized for charging 1-cell and 2-cell Li-ion or
Li-polymer batteries. It charges a battery with constant
current (CC) and constant voltage (CV) profile. The
typical charge profile is illustrated in Figure 5.
POR and Power-Good
The ISL9220, ISL9220A resets itself when V
transition from below V
The ISL9220, ISL9220A has an internal PGOOD signal.
Charging is prohibited if PGOOD statement is not true.
See Note 6 in the “Electrical Specifications” table for the
definition of PGOOD.
Valid Charge Temperatures
An external NTC thermistor can be used to provide
temperature-qualified charging. The V
as reference for the internal comparators. Thus, it is
important that the V
external voltage divider comprised of one or more fixed
resistors and the thermistor. This scheme allows the use
of a wide variety of thermistors. The RTH comparator
block monitors the RTH pin voltage to determine if the
battery temperature is within safe charging limits.
The ISL9220, ISL9220A uses two comparators (CP2 and
CP3) to form a window comparator, as shown in
Figure 6. When the NTC pin voltage is “out of the
window,” determined by the V
ISL9220, ISL9220A stops charging and indicate a
suspend condition. When the temperature returns to
the set range, the charger resumes charging. The two
MOSFETs, Q1 and Q2, produce hysteresis for both upper
and lower thresholds. The temperature window is
shown in Figure 7 for a 0°C to +50°C typical application
using an industry standard type 103AT thermistor.
The temperature qualification function can be disabled by
connecting the RTH pin to ground.
FIGURE 5. TYPICAL CHARGE PROFILE
BIAS
POR
supply also be used to bias the
9
to above V
TMIN
and V
BIAS
POR
TMAX
supply is used
threshold.
IN
ISL9220, ISL9220A
undergoes
, the
Battery Detection
The presence or absence of the external thermistor is
used to detect a battery.
When V
pin is not connected to ground, battery detection is
provided by the RTH comparator block, as shown in
Figure 6. With no battery connected, the RTH pin is pulled
to V
threshold. The internal battery presence signal is deglitched
with a 12ms deglitcher, to avoid false indication of battery
insertion or removal due to contact bounce or other noises.
Battery Precharge
When the charger is first enabled and no fault conditions
are detected, if the battery connecting to the charger is
deeply discharged, the charger will charge the battery in
a reduced current for the battery to recover.
If the battery voltage is less than the level 1 pre-charge
voltage (V
an output current fixed at 50mA typical. In this mode, the
output voltage can go to 0V. This provides the ability to
recover a battery that has entered a safety-circuit
undervoltage fault mode.
FIGURE 7. THRESHOLD VOLTAGES FOR 0°C to +50°C
BIAS
FIGURE 6. THERMISTOR INTERNAL CIRCUIT
RTH
by R
PCHG1
is greater than V
WINDOW (V
U
, and thus V
), the charger operates in LDO mode, with
BIAS
RTH
RTH,PRES
will exceed the V
= 5.0V)
, i.e. when the RTH
February 8, 2011
RTH,NOBAT
FN6936.2