MCP73811 MICROCHIP [Microchip Technology], MCP73811 Datasheet - Page 10

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

MCP73811/2
4.0
The MCP73811/2 are simple, but fully integrated linear
charge management controllers.
operational flow algorithm.
FIGURE 4-1:
4.1
The MCP73811/2 does not have an internal under
voltage lockout (UVLO) circuit.
4.2
When the input power is applied, the input supply must
rise 150 mV above the battery voltage before the
MCP73811/2 becomes operational.
The automatic power down circuit places the device in
a shutdown mode if the input supply falls to within
+50 mV of the battery voltage.
The automatic circuit is always active. Whenever the
input supply is within +50 mV of the voltage at the V
pin, the MCP73811/2 is placed in a shutdown mode.
During power down condition, the battery reverse dis-
charge current is less than 2 µA.
For a charge cycle to begin, the automatic power down
conditions must be met and the charge enable input
must be above the input high threshold.
DS22036A-page 10
V
BAT
DEVICE OVERVIEW
Undervoltage Lockout (UVLO)
Charge Qualification
< V
REG
CONSTANT CURRENT
CONSTANT VOLTAGE
Charge Voltage = V
Charge Current = I
SHUTDOWN MODE*
STANDBY MODE*
* Continuously
V
CE = Low
Monitored
DD
Flow Chart.
MODE
MODE
< V
PD
Figure 4-1
REG
REG
V
BAT
= V
depicts the
REG
BAT
4.3
The MCP73811/2 does not support preconditioning of
deeply depleted cells.
4.4
During the constant current mode, the selected
(MCP73811) or programmed (MCP73812) charge
current is supplied to the battery or load.
For the MCP73812, the charge current is established
using a single resistor from PROG to V
resistor and the charge current are calculated using the
following equation:
EQUATION 4-1:
Constant current mode is maintained until the voltage
at the V
4.5
When the voltage at the V
regulation voltage, V
begins. The regulation voltage is factory set to 4.20V
with a tolerance of ±1.0%.
4.6
The charge cycle is terminated by removing the battery
from the charger, removing input power, or driving the
charge enable input (CE) to a logic Low. An automatic
charge termination method is not implemented.
4.7
The MCP73811/2 does not support automatic recharge
cycles since automatic charge termination has not
been implemented. In essence, the MCP73811/2 is
always in a charge cycle whenever the qualification
parameters have been met.
Where:
BAT
R
PRECONDITIONING
Constant Current MODE - Fast
Charge
Constant Voltage Mode
Charge Termination
Automatic Recharge
PROG
I
REG
pin reaches the regulation voltage, V
I
=
=
REG
REG
© 2007 Microchip Technology Inc.
, constant voltage regulation
=
kilo-ohms
milliamperes
---------------- -
R
1000V
PROG
BAT
pin reaches the
SS
. The program
REG
.