LTC4010CFEPBF LINER [Linear Technology], LTC4010CFEPBF Datasheet - Page 15

• Manufacturer Part Number: LTC4010CFEPBF
• Description: High Efficiency Standalone Nickel Battery Charger
• Manufacturer: LINER [Linear Technology]

applicaTions inForMaTion
charging states. To some degree, the value should reflect
how closely the programmed charge current matches the
1C rate of targeted battery packs. The maximum fast charge
period is determined by the following equation:
Some typical timing values are detailed in Table 3. R
should not be less than 15k. The actual time limits used
by the LTC4010 have a resolution of approximately ±30
seconds in addition to the tolerances given the Electrical
Characteristics table. If the timer ends without a valid
–∆V or ∆T/∆t charge termination, the charger enters the
fault state. The maximum time period is approximately
4.3 hours.
Cell Voltage Network Design
An external resistor network is required to provide the
average single-cell voltage to the V
R
TIMER
Table 2. LTC4010 Charging Parameters
PC:
FC:
TOC: Top-Off Charge (Only for NiMH ∆T/∆t FC Termination After Initial t
AR:
Table 3. LTC4010 Time Limit Programming Examples
STATE
TOC
PC
AR
FC
R
24.9k
33.2k
49.9k
66.5k
100k
=
Precharge
Fast Charge (Initial –∆V Termination Hold Off of t
Automatic Recharge (Temperature Limits Apply to State Termination Only)
TIMER
t
MAX
30 10
CHEM
Open
GND
GND
•
PIN
(
Hours
TYPICAL FAST
CHARGE RATE
–
6
CHEMISTRY
0.75C
1.5C
)
C/2
2C
1C
( )
NiMH
NiMH
Both
NiCd
Both
Ω
BAT
CELL
t
PRECHARGE LIMIT
TIMER
t
MAX
MAX
t
t
pin of the LTC4010.
MAX
MAX
(MINUTES)
/12
/3
7.5
3.8
10
15
5
T
5°C
5°C
5°C
5°C
5°C
MIN
MAX
/12 Minutes May Apply)
TIMER
T
45°C
60°C
60°C
60°C
45°C
MAX
VOLTAGE STABILIZATION
FAST CHARGE
MAX
The proper circuit for multicell packs is shown in Figure 3.
The ratio of R2 to R1 should be a factor of (n – 1), where
n is the number of series cells in the battery pack. The
value of R1 should be between 1k and 100k. This range
limits the sensing error caused by V
and prevents the ON resistance of the internal NFET be-
tween V
the V
used to detect battery insertion and removal. The filter
(MINUTES)
I
I
PROG
PROG
I
I
I
CHRG
PROG
PROG
/12 Period)
3.8
7.5
10
15
0
5
/10 Timer Expires
CELL
/5 Timer Expires
CDIV
V
–10mV per Cell or 1°C/Minute After t
or if Initial V
TERMINATION CONDITION
–20mV per Cell or 2°C/Minute
1.5°C/Minute for First t
V
CELL
CELL
voltage. The external resistor network is also
Figure 3. Multiple Cell Voltage Divider
and GND from causing a significant error in
< 1.325V
< 1.325V
LTC4010
FAST CHARGE LIMIT
CELL
V
V
> 1.325V
CELL
GND
CDIV
(HOURS)
BAT
0.75
1.5
1
2
3
10
MAX
6
7
4
4010 F03
/12 Minutes if Initial
MORE SERIES CELLS
R2
R1
R2 = R1(n – 1)
FOR TWO OR
CELL
MAX
+
(MINUTES)
LTC4010
/12 Minutes
TOP-OFF
CHARGE
C1
leakage current
15
20
30
40
60

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