MCP73826 Microchip Technology, MCP73826 Datasheet - Page 10

• Manufacturer Part Number: MCP73826
• Description: Single Cell Lithium-Ion Charge Management Controller
• Manufacturer: Microchip Technology

MCP73826
5.0
Refer to the typical application circuit, Figure 6-1.
5.1
5.1.1
The MCP73826 monitors the cell voltage at the
pin. This input is tied directly to the positive terminal of
the battery. The MCP73826 is offered in two fixed-volt-
age versions for single cells with either coke or graphite
anodes:
(MCP73826-4.2).
5.1.2
The MCP73826 controls the gate drive to an external
P-channel MOSFET, Q1. The P-channel MOSFET is
controlled in the linear region, regulating current and
voltage supplied to the cell. The drive output is auto-
matically turned off when the input supply falls below
the voltage sensed on the
5.1.3
The V
MCP73826 automatically enters a power-down mode if
the voltage on the V
the
pack when the V
5.1.4
Fast charge current regulation is maintained by the
voltage drop developed across an external sense resis-
tor, R
ing formula calculates the value for R
Where:
DS21705A-page 10
V
V
I
amps. The preconditioning current is scaled to
approximately 43% of I
BAT
OUT
SENSE
IN
CS
input is the input supply to the MCP73826. The
is the current limit threshold
pin. This feature prevents draining the battery
DETAILED DESCRIPTION
Analog Circuitry
OUTPUT VOLTAGE INPUT (
GATE DRIVE OUTPUT (V
SUPPLY VOLTAGE (V
CURRENT SENSE INPUT (V
is the desired peak fast charge current in
, applied to the V
4.1V
IN
supply is not present.
R
IN
SENSE
(MCP73826-4.1)
input falls below the voltage on
V
OUT
=
BAT
SNS
----------- -
I
V
O UT
.
input.
CS
IN
input pin. The follow-
)
DRV
SENSE
V
SNS
)
BAT
and
)
)
:
4.2V
V
BAT
5.2
5.2.1
The shutdown input pin, SHDN, can be used to termi-
nate a charge anytime during the charge cycle, initiate
a charge cycle, or initiate a recharge cycle.
Applying a logic High input signal to the SHDN pin, or
tying it to the input source, enables the device. Apply-
ing a logic Low input signal disables the device and ter-
minates a charge cycle. In shutdown mode, the
device’s supply current is reduced to 0.5 µA, typically.
Digital Circuitry
SHUTDOWN INPUT (SHDN)
2002 Microchip Technology Inc.