MCP73861-I/SL Microchip Technology Inc., MCP73861-I/SL Datasheet - Page 13

• Manufacturer Part Number: MCP73861-I/SL
• Description: Highly-Integrated Single Cell Lithium-Ion/Lithium-Polymer Charge Management Cont
• Manufacturer: Microchip Technology Inc.

Specifications of MCP73861-I/SL

• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

4.0
The MCP7386X family of devices are highly advanced
linear charge management controllers. Refer to the
functional block diagram. Figure 4-2 depicts the
operational flow algorithm from charge initiation to
completion and automatic recharge.
4.1
Upon insertion of a battery, or application of an external
supply, the MCP7386X family of devices automatically
performs a series of safety checks to qualify the
charge. The input source voltage must be above the
Undervoltage Lockout (UVLO) threshold, the enable
pin must be above the logic-high level and the cell
temperature must be within the upper and lower
thresholds.
continuously monitored. Deviation beyond the limits
automatically suspends or terminates the charge cycle.
The input voltage must deviate below the UVLO stop
threshold for at least one clock period to be considered
valid.
Once the qualification parameters have been met, the
MCP7386X initiates a charge cycle. The charge status
output is pulled low throughout the charge cycle (see
Table 5-1 for charge status outputs). If the battery
voltage is below the preconditioning threshold (V
the MCP7386X preconditions the battery with a trickle-
charge. The preconditioning current is set to approxi-
mately 10% of the fast charge regulation current. The
preconditioning
deeply depleted cells and minimizes heat dissipation
during the initial charge cycle. If the battery voltage has
not exceeded the preconditioning threshold before the
preconditioning timer has expired, a fault is indicated
and the charge cycle is terminated.
4.2
Preconditioning ends, and fast charging begins, when
the battery voltage exceeds the preconditioning thresh-
old. Fast charge regulates to a constant current (I
which is set via an external resistor connected to the
PROG pin. Fast charge continues until the battery
voltage reaches the regulation voltage (V
fast charge timer expires; in which case, a fault is
indicated and the charge cycle is terminated.
4.3
When the battery voltage reaches the regulation
voltage (V
The MCP7386X monitors the battery voltage at the
V
terminal of the battery. The MCP7386X selects the
voltage regulation value based on the state of V
With V
© 2005 Microchip Technology Inc.
BAT
pin. This input is tied directly to the positive
SET
DEVICE OVERVIEW
Charge Qualification and
Preconditioning
Constant Current Regulation –
Fast Charge
Constant Voltage Regulation
REG
tied to V
The
), constant voltage regulation begins.
trickle-charge
qualification
SS
, the MCP73861/3 and
safely
parameters
REG
replenishes
), or the
REG
PTH
SET
are
),
),
.
MCP73862/4 regulate to 4.1V and 8.2V, respectively.
With V
MCP73862/4 regulate to 4.2V and 8.4V, respectively.
4.4
The MCP7386X monitors the charging current during
the Constant-voltage regulation mode. The charge
cycle is considered complete when the charge current
has diminished below approximately 8% of the
regulation current (I
expired.
The MCP7386X automatically begins a new charge
cycle when the battery voltage falls below the recharge
threshold (V
parameters are met.
4.5
The MCP7386X family limits the charge current based
on the die temperature. Thermal regulation optimizes
the charge cycle time while maintaining device reliabil-
ity. If thermal regulation is entered, the timer is automat-
ically slowed down to ensure that a charge cycle will
not terminate prematurely. Figure 4-1 depicts the
thermal regulation profile.
FIGURE 4-1:
Current vs. Die Temperature.
4.6
The MCP7386X family suspends charge if the die
temperature exceeds 155°C. Charging will resume
when the die temperature has cooled by approximately
10°C. The thermal shutdown is a secondary safety
feature in the event that there is a failure within the
thermal regulation circuitry.
1400
1200
1000
800
600
400
200
SET
0
Charge Cycle Completion and
Automatic Re-Charge
Thermal Regulation
Thermal Shutdown
0
MCP73861/2/3/4
tied to V
RTH
20
), assuming all the qualification
40
REG
Typical Maximum Charge
Die Temperature (° C)
DD
), or the elapsed timer has
60
, the MCP73861/3 and
Minimum
80
DS21893C-page 13
100
120
Maximum
140