isl9203crz-t Intersil Corporation, isl9203crz-t Datasheet - Page 12

• Manufacturer Part Number: isl9203crz-t
• Description: Li-ion/li Polymer Battery Charger
• Manufacturer: Intersil Corporation

Recharge
After a charge cycle completes, charging is prohibited until
the battery voltage drops to a recharge threshold, V
(see Electrical Specifications). Then a new charge cycle
starts at point t
The safety timer is reset at t
Internal Oscillator
The internal oscillator establishes a timing reference. The
oscillation period is programmable with an external timing
capacitor, C
oscillator charges the timing capacitor to 1.5V and then
discharges it to 0.5V in one period, both with 10PA current.
The period T
A 1nF capacitor results in a 0.2ms oscillation period.The
accuracy of the period is mainly dependent on the accuracy
of the capacitance and the internal current source.
Total Charge Time
The total charge time for the CC mode and CV mode is
limited to a length of TIMEOUT. A 22-stage binary counter
increments each oscillation period of the internal oscillator to
set the TIMEOUT. The TIMEOUT can be calculated as:
or
A 1nF capacitor leads to 14 minutes of TIMEOUT. For
example, a 15nF capacitor sets the TIMEOUT to be 3.5
hours. The charger has to reach the end-of-charge condition
before the TIMEOUT, otherwise, a TIMEOUT fault is issued.
The TIMEOUT fault latches up the charger. There are two
ways to release such a latch-up: either to recycle the input
power, or toggle the EN pin to disable the charger and then
enable it again.
The trickle mode charge has a time limit of 1/8 TIMEOUT. If
the battery voltage does not reach V
TIMEOUT fault is issued and the charger latches up. The
charger stays in trickle mode for at least 15 cycles of the
internal oscillator and, at most, 1/8 of TIMEOUT, as shown in
Figure 20.
Charge Current Programming
The charge current in the CC mode is programmed by the
IREF pin. The voltage of IREF is regulated to a 0.8V
reference voltage. The charging current during the constant
T
TIMEOUT
OSC
TIMEOUT
=
0.2 10
=
TIME
˜
OSC
=
14
6
2
6
and ends at point t
22
˜
, as shown in Typical Applications. The
˜
is:
C
----------------- -
C
1nF
˜
TIME
TIME
T
OSC
6
12
.
minutes
sec
onds
8
, as shown in Figure 20.
MIN
within this limit, a
RECHRG
(EQ. 3)
(EQ. 4)
(EQ. 5)
ISL9203
current mode is 100,000 times that of the current in the
R
Table 1 shows the charge current vs. selected R
The typical trickle charge current is 10% of the programmed
constant charge current. Table 2 shows the trickle charge
current tolerance guidance at given R
battery voltage is between 0V to 2.5V. Use this guidance
only for mass production tests in customer’s products.
The ISL9203 is designed to be safe when the IREF pin is
accidentally short-circuited to an external source or to
ground. If the IREF pin is driven by an external source to
below 0.38V or above 1.5V for any reason, the charger is
disabled and the FAULT pin turns to LOW to indicate a fault
I
REF
IREF
TABLE 2. TRICKLE CHARGE CURRENT vs R
R
R
R
267 ~ 160
=
IREF
IREF
IREF
TABLE 1. CHARGE CURRENT vs R
resistor. Hence, the charge current is,
88.9
88.9
88.9
160
100
267
160
100
267
160
100
---------------- -
R
80
80
80
0.8V
TABLE 3. EOC CURRENT vs R
IREF
(k:)
(k:)
(k:)
u
10
5
17% lower than
A
TYP Value
TRICKLE CHARGE CURRENT (mA)
MIN
MIN
MIN
450
720
810
900
15
30
40
45
70
15
20
40
45
70
CHARGE CURRENT (mA)
EOC CURRENT (mA)
in EQ. 5
= I
1000
TYP
TYP
TYP
500
800
900
100
100
30
50
80
90
30
50
80
90
IREF
REF
IREF
IREF
values, when the
VALUES.
17% higher than
IREF
VALUES.
TYP Value
IREF
February 3, 2005
MAX
1100
VALUES.
MAX
MAX
550
880
990
120
135
150
120
135
150
60
80
60
80
values.
FN6106.0
(EQ. 6)