LTC4110EUHF LINER [Linear Technology], LTC4110EUHF Datasheet - Page 38

• Manufacturer Part Number: LTC4110EUHF
• Description: Battery Backup System Manager
• Manufacturer: LINER [Linear Technology]

LTC4110
APPLICATIONS INFORMATION
fl oat voltage = 2.5V at 25°C with a temperature coeffi cient of
–2mV/°C, then R1 = 7256, k1 = 0.580, TCk1 = –10.3m/°C,
ΔV
PROGRAMMING CURRENT
Charge/calibration currents are programmed using the
following equations:
where:
I
I
I
V
38
CHG
PCC
CAL
BGR
I
I
I
FLOAT
CHG
PCC
CAL
k2 =
= calibration current
= preconditioning charge current
= bulk charge current
= 1.220V
Figure 16. Lead Acid Temperature Compensation
R2 + R3
=
=
=
= 2.5 – 2.35 = 0.15V, k2 = 0.162, k3 = 0.634.
R2
R
R
R
SNS B
SNS BAT
SNS BAT
V
V
V
BGR
BGR
BGR
(
(
R2
R3
(
A A T
)
)
)
•
•
•
R
R
R
R
R
R
IPCC
ICAL
ICHG
CSN
CSP
+
–
+
–
CSP
(1 – k3) • R
k3 • R
R1
k1 =
R
10k
VREF
NTC
R0 + R1
VREF
R0
V
V
THA
THB
REF
CHG
4110 F16
R
battery
R
R
R
R
R
If any programming resistor value on any of the three
pins exceeds 100k, see Flyback Compensation section
for more information.
Pins can be tied together to save components if any of
the currents have the same value. If two pins share a
common programming resistor greater than 100k, only
one compensation circuit is required.
If the TYPE pin is set for SLA/LEAD ACID, then the I
pin is not used. You can leave the I
PROGRAMMING BACKUP MODE ENTRY THRESHOLD
AND CALIBRATION MODE BACK-DRIVE VOLTAGE
DETECTION THRESHOLD
A resistor divider connected to supply input sets both the
backup mode entry threshold and the calibration mode
back-drive voltage detection threshold.
where:
V
not be programmed to less than 4.5V
V
it should not be programmed to more than 20V
V
mode, typically 1.5V (see V
BACKUP
BACKDRIVE
OVP
SNS(BAT)
CSP
CSN
ICHG
IPCC
ICAL
V
V
R2
R1
BACKUP
BACKDRIVE
= DCDIV pin back-drive detect threshold in calibration
= R
= R
= resistor connected between I
= resistor connected between I
= resistor connected between I
=
CSP1
= supply voltage when backup starts, it should
CSN1
V
BACKUP
= resistor between fl yback transformer and
V
= supply voltage when calibration is terminated,
BGR
=
+ R
+ R
=
R2
R1
CSP2
CSN2
V
V
+ 1 • V
OVP
BGR
1
• V
BGR
OVP
BACKUP
)
PCC
CAL
PCC
CHG
pin open.
pin and GND.
pin and GND
pin and GND
4110fa
PCC