MCP73811 MICROCHIP [Microchip Technology], MCP73811 Datasheet - Page 12

• Manufacturer Part Number: MCP73811
• Description: Simple, Miniature Single-Cell, Fully Integrated Li-Ion / Li-Polymer Charge Management Controllers
• Manufacturer: MICROCHIP [Microchip Technology]

MCP73811/2
5.0
5.1
5.1.1
The V
The MCP73811/2 automatically enters a Power-down
mode if the voltage on the V
+50 mV of the battery voltage. This feature prevents
draining the battery pack when the V
present.
5.1.2
For the MCP73812, the charge current regulation can
be scaled by placing a programming resistor (R
from the PROG input to V
the charge current are calculated using the following
equation:
EQUATION 5-1:
5.1.3
The battery charge control output is the drain terminal
of an internal P-channel MOSFET. The MCP73811/2
provides constant current and voltage regulation to the
battery pack by controlling this MOSFET in the linear
region. The battery charge control output should be
connected to the positive terminal of the battery pack.
DS22036A-page 12
Where:
DD
R
DETAILED DESCRIPTION
Analog Circuitry
input is the input supply to the MCP73811/2.
PROG
I
BATTERY MANAGEMENT INPUT
SUPPLY (V
MCP73812 CURRENT REGULATION
SET (PROG)
REG
BATTERY CHARGE CONTROL
OUTPUT (V
I
=
=
REG
DD
=
BAT
SS
kilo-ohms
milliamperes
)
. The program resistor and
---------------- -
R
1000V
)
PROG
DD
input falls to within
DD
supply is not
PROG
)
5.2
5.2.1
The charge enable input pin (CE) can be used to
terminate a charge at any time during the charge cycle,
as well as to initiate a charge cycle or initiate a recharge
cycle.
Driving the input to a logic High enables the device.
Driving the input to a logic Low disables the device and
terminates a charge cycle. When disabled, the device’s
supply current is reduced to 50 µA, typically.
5.2.2
For the MCP73811, driving the PROG input to a logic
Low selects the low charge current setting (85 mA).
Driving the PROG input to a logic High selects the high
charge current setting (450 mA).
Digital Circuitry
CHARGE ENABLE (CE)
MCP73811 CURRENT REGULATION
SELECT (PROG)
© 2007 Microchip Technology Inc.