LTC4110
33
4110fb
based on the desired cap voltage and series cell count.
Other per cell voltages can be obtained by adjusting the
V
CHG
pin as required.
When the LTC4110 is confi gured to charge a super cap,
if TYPE pin is tied to 0.5V
REF
, use the bulk charge current
equation (see the Programming Charging/Calibration Cur-
rent section for details) to set the charging current. If TYPE
pin is tied to GND, then the charging current will equal
to preconditioning charge current when the cap voltage
is below the bulk charge threshold (as listed in Table 9)
and bulk charge current when the voltage is above the
threshold. Simply tie the I
PCC
pin to I
CHG
pin if these two
currents need to be the same. If the capacitor is too small
(<10mF), the voltage might rise too fast to be regulated
by the loop. In that case, the capacitor will be charged to
over voltage pretection threshold (typically 107.5% of the
fl oat voltage. See V
BOV
)
The fi rst confi guration option to set for the LTC4110 is the
type and cell count of the battery you wish to use. Pins
TYPE and SELC are use to set this confi guration. Please
note NiMH and NiCd batteries are only supported in the
smart battery confi guration. The three state input pins
SELA, SELC and TYPE should NOT be changed while power
is applied to the IC unless in shutdown mode. Such action
will result in unpredictable behavior from the LTC4110.
SUPERCAPS
Table 8 shows all of the options with the exception of
SuperCaps. SuperCaps are supported by using standard
Li-ion or SLA modes in combination with the adjusting the
charge voltage with the V
CHG
pin. As far as the LTC4110
is concerned, it is still working with a Li-ion or SLA bat-
tery and will follow all the charge states as required for
that chemistry. Table 9 shows the required confi guration
APPLICATIONS INFORMATION
Table 8. Battery Type and Number of Series Cell Selection for Batteries
STANDARD
Li-Ion
(TYPE = GND)
SLA
(TYPE = 0.5V
REF
)
SMART NiMH/NiCd
(TYPE = V
REF
)
SMART Li-Ion
(TYPE = V
DD
)
SELC = GND
1
2
4
1
SELC = 0.5V
REF
2
3
6
2
SELC = V
REF
3
5
9
3
SELC = V
DD
4
6
10
4
Note: When smart battery is selected by the TYPE pin, SELA pin must be connected to GND to select address 12h.
Table 9. Battery Type and Number of Series Cell Selection for Super Caps
CAP VOLTAGE (V)
SERIES CAP
COUNT
STACK CAP
VOLTAGE (V)
TYPE
SELC
V
CHG
BULK CHARGE
THRESHOLD (V/CELL)
2.5
2
5
0.5V
REF
GND
0.625V
REF
N/A
2.5
3
7.5
0.5V
REF
0.5V
REF
0.625V
REF
N/A
2.5
5
12.5
0.5V
REF
V
REF
0.625V
REF
N/A
2.5
6
15
0.5V
REF
V
DD
0.625V
REF
N/A
2.5
7
17.5
GND
V
DD
0.646V
REF
1.71
2.7
3
8.1
GND
0.5V
REF
0.375V
REF
2
2.7
5
13.5
GND
V
REF
0.750V
REF
1.8
2.7
6
16.2
GND
V
DD
0.375V
REF
2
3
3
9
GND
0.5V
REF
0.750V
REF
2
3
4
12
GND
V
REF
0.333V
REF
2.25
3
5
15
0.5V
REF
V
DD
0.625V
REF
N/A
3
6
18
GND
V
DD
0.750V
REF
2
