Datasheet

 2009-2013 Microchip Technology Inc. DS20002183E-page 19
MCP73113/4
5.9 Thermal Regulation
The MCP73113/4 shall limit the charge current based
on the die temperature. The thermal regulation
optimizes the charge cycle time while maintaining
device reliability. Figure 5-1 depicts the thermal
regulation for the MCP73113/4 device. Refer to
Section 1.0 “Electrical Characteristics” for thermal
package resistances and Section 6.1.1.2 “Thermal
Considerations” for calculating power dissipation.
.
FIGURE 5-1: Charge Current (I
OUT
) vs.
Junction Temperature (T
J
).
5.10 Thermal Shutdown
The MCP73113/4 suspends the charge if the die
temperature exceeds +150°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.
5.11 Status Indicator
The charge status outputs are open-drain outputs with
two different states: Low (L), and High-Impedance
(high-Z). The charge status outputs can be used to
illuminate LEDs. Optionally, the charge status outputs
can be used as an interface to a host microcontroller.
Table 5-2 summarizes the state of the status outputs
during a charge cycle.
5.12 Battery Short Circuit Protection
When a single-cell Li-Ion battery is detected, an inter-
nal battery short circuit protection (BSP) circuit starts
monitoring the battery voltage. When V
BAT
is below the
typical 1.7V battery short circuit protection threshold
voltage, the charging behavior is postponed. A 25 mA
(typical) detection current is supplied for recovering
from the battery short circuit condition.
Preconditioning mode resumes when V
BAT
raises
above the battery short circuit protection threshold. The
battery voltage must rise approximately 150 mV above
the battery short circuit protection voltage before the
MCP73113/4 device becomes operational.
0
100
200
300
400
500
600
25 35 45 55 65 75 85 95 105 115 125 135 145
Junction Temperature (°C)
Charge Current (mA)
V
DD
= 5.2V
R
PROG
= 2 kΩ
TABLE 5-2: STATUS OUTPUTS
CHARGE CYCLE STATE STAT
Shutdown high Z
Standby high Z
Preconditioning L
Constant Current Fast
Charge
L
Constant Voltage L
Charge Complete - Standby high Z
Temperature Fault 1.6 second 50% D.C.
Flashing (Type2)
high Z (Type 1)
Timer Fault 1.6 second 50% D.C.
Flashing (Type 2)
high Z (Type 1)
Preconditioning Timer Fault 1.6 second 50% D.C.
Flashing (Type 2)
high Z (Type 1)