LTM8062IV#PBF Linear Technology, LTM8062IV#PBF Datasheet - Page 12

• Manufacturer Part Number: LTM8062IV#PBF
• Description: IC, BATT CHRG, Li-Ion, Li-Polymer, 2A, LGA77
• Manufacturer: Linear Technology

Specifications of LTM8062IV#PBF

• Battery Type: Li-Ion, Li-Polymer
• Input Voltage: 32V
• Battery Charge Voltage: 14.4V
• Charge Current Max: 2A
• Battery Ic Case Style: LGA
• No. Of Pins: 77
• No. Of Series Cells: 1

APPLICATIONS INFORMATION
LTM8062
application. As the temperature characteristic for a typical
solar panel V
for tracking that characteristic can be implemented using a
Linear Technology LM234 3-terminal temperature sensor.
This creates an easily programmable, linear temperature
dependent characteristic.
In the circuit shown in Figure 4,
where TC = temperature coefficient (in V/°C), and
V
12
For example, given a common 36-cell solar panel that has
the following specified characteristics:
MP
Open Circuit Voltage (V
Maximum Power Voltage (V
Open-Circuit Voltage Temperature Coefficient (V
= –78mV/°C
R
R
(25°C) = maximum power voltage at 25°C.
TC • 4405 • V
Figure 4. MPPT Temperature Compensation Network
IN
SET
=
V
MP
100V
= 100
V
IN
1–
(25  C)
MP
V
MP
INREG
100 •
V
voltage is highly linear, a simple solution



INREG
INREG
R
TC • 4405
(25  C)
IN
0.0677
V
V
1



+
–
•
R
k
– 100
SET
OC
R
+
LINEAR
TECHNOLOGY
LM234
) = 21.7V
0.0677
V
R
MP
INREG
SET
k
) = 17.6V
V
INREG
LTM8062
–
V
IN
8062 F04
OC
)
As the temperature coefficient for V
V
–78mV/°C and the specified peak power voltage (V
of 17.6V can be inserted into the equations to calculate the
appropriate resistor values for the temperature compen-
sation network in Figure 4. With R
Battery Voltage Temperature Compensation
Some battery chemistries have charge voltage require-
ments that vary with temperature. Lead-acid batteries in
particular experience a significant change in charge volt-
age requirements as temperature changes. For example,
manufacturers of large lead-acid batteries recommend
a float charge of 2.25V/cell at 25°C. This battery float
voltage, however, has a temperature coefficient which is
typically specified at –3.3mV/°C per cell.
In a manner similar to the MPPT temperature correction
outlined previously, implementation of linear battery charge
voltage temperature compensation can be accomplished by
incorporating a Linear Technology LM234 into the output
feedback network. For example, a 6-cell lead acid battery
has a float charge voltage that is commonly specified at
2.25V/cell at 25°C, or 13.5V, and a –3.3mV/°C per cell tem-
perature coefficient, or –19.8mV/°C. Using the feedback
OC

, the specified temperature coefficient for V
R
= 4.12k
R
–78mV /  C • 4405 • 2.7
IN
SET
=
= 100
100 • 17.6V
1–
17.6
100 • 0.0677
2.7



2.7 • 4.1
–78mV /  C • 4405
– 100
1



1400 k
k
MP
SET
+
is similar to that of
equal to 1k, then:
0.0677
2.7
MP
OC
–
(25°C))
(TC) of
8062fa