MCP73833 Microchip Technology, Inc., MCP73833 Datasheet - Page 15

• Manufacturer Part Number: MCP73833
• Description: 1A output current linear charge management controller. Includes integrated pass transistor, integrated current sensing, and reverse discharge protection. Also includes safety features such as cell temperature monitoring, on-chip thermal regulation an
• Manufacturer: Microchip Technology, Inc.

6.0
The MCP73833/4 is designed to operate in conjunction
with a host microcontroller or in stand-alone applica-
tions. The MCP73833/4 provides the preferred charge
algorithm for Lithium-Ion and Lithium-Polymer cells
FIGURE 6-1:
FIGURE 6-2:
Thermal Regulation (1700 mAh Li-Ion Battery).
FIGURE 6-3:
with Thermal Regulation (1700 mAh Li-Ion
Battery).
© 2006 Microchip Technology Inc.
5.0
4.0
3.0
2.0
1.0
0.0
5.0
4.0
3.0
2.0
1.0
0.0
Regulated
Wall Cube
APPLICATIONS
MCP73833-FCI/MF
V
R
DD
PROG
= 5.2V
= 1.00 k
Time (Minutes)
Time (Minutes)
Typical Application Circuit.
Typical Charge Profile with
Typical Charge Cycle Start
C IN
MCP73833-FCI/MF
R
LED
PROG
V
= 1.00 k
DD
= 5.2V
LED
2.00
1.60
1.20
0.80
0.40
0.00
2.00
1.60
1.20
0.80
0.40
0.00
LED
R
R
R
LED
LED
LED
1,2
3
4
7
Li-Ion Battery Charger
V
STAT1
STAT2
PG
Constant-current
Figure 6-1
circuit,
accompanying charge profile.
6.1
Due to the low efficiency of linear charging, the most
important factors are thermal design and cost, which
are a direct function of the input voltage, output current
and thermal impedance between the battery charger
and the ambient cooling air. The worst-case situation is
when
Preconditioning mode to the Constant-current mode. In
this situation, the battery charger has to dissipate the
maximum power. A trade-off must be made between
the charge current, cost and thermal requirements of
the charger.
6.1.1
Selection of the external components in
crucial to the integrity and reliability of the charging
system. The following discussion is intended as a guide
for the component selection process.
6.1.1.1
The preferred fast charge current for Lithium-Ion cells
is at the 1C rate, with an absolute maximum current at
the 2C rate. For example, a 500 mAh battery pack has
a preferred fast charge current of 500 mA. Charging at
this rate provides the shortest charge cycle times
without degradation to the battery pack performance or
life.
DD
MCP73833
THERM
PROG
the
Application Circuit Design
while
V
V
BAT
SS
depicts a typical stand-alone application
COMPONENT SELECTION
Current Programming Resistor
(R
device
9,10
8
6
5
PROG
Figures
followed
R
MCP73833/4
R
)
T1
C
has
PROG
OUT
6-2
transitioned
by
R
and
T2
6-3
DS22005A-page 15
Constant-voltage.
T
+
-
Figure 6-1
Single
Li-Ion
Cell
10 kΩ
depict
from
the
the
is