MCP73862-I/MLG Microchip Technology, MCP73862-I/MLG Datasheet - Page 18

• Manufacturer Part Number: MCP73862-I/MLG
• Description: IC CONTROLLER LI-ION 8.2V 16QFN
• Manufacturer: Microchip Technology

Specifications of MCP73862-I/MLG

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion), Lithium-Polymer (Li-Pol)
• Voltage - Supply: 8.7 V ~ 12 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-QFN
• Output Voltage: 8.2 V, 8.4 V
• Output Current: 1200 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: MCP73862-I/MLG; MCP73862-I/MLGR

MCP73861/2
FIGURE 6-3:
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 the device has transitioned from the Precondi-
tioning 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 Figure 6-1 is
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 with-
out degradation to the battery pack performance or life.
DS21893B-page 18
Application Circuit Design
COMPONENT SELECTION
Regulation
Voltage
(V
Regulation
Current
(I
Transition
Threshold
(V
Precondition
Current
(I
Termination
Current
(I
REG
PREG
TERM
Current Programming Resistor
(R
REG
PTH
PROG
)
)
)
)
)
)
Typical Charge Profile in Thermal Regulation.
Preconditioning
Mode
Precondition
Safety Timer
Charge
Voltage
Fast Charge
Safety Timer
Constant-Current
Mode
Elapsed Time
Termination Timer
1200 mA is the maximum charge current obtainable
from the MCP7386X. For this situation, the PROG input
should be connected directly to V
6.1.1.2
The worst-case power dissipation in the battery
charger occurs when the input voltage is at the
maximum and the device has transitioned from the
Preconditioning mode to the Constant-current mode. In
this case, the power dissipation is:
Where:
PowerDissipation
V
I
V
REGMAX
DDMAX
PTHMIN
Thermal Considerations
is the maximum input voltage
voltage.
is the maximum fast charge current
is the minimum transition threshold
Charge
Current
Constant-Voltage
Mode
=
V
DDMAX
 2005 Microchip Technology Inc.
–
V
PTHMIN
SS
.
I
REGMAX