MCP73113_13 Datasheet, PDF (18/34 Pages) Microchip Technology – Single-Cell Li-Ion/Li-Polymer Battery Charge Management Controller with Input Overvoltage Protection

MCP73113/4
5.5 Constant Current MODE – Fast
Charge
During the Constant-Current mode, the programmed
charge current is supplied to the battery or load.
The charge current is established using a single
resistor from PROG to V_SS. The program resistor and
the charge current are calculated using the following
equations:
EQUATION 5-1:
I_REG = 1104  R^–0.93
Where:
R_PROG = kilo-ohms (k)
I_REG = milliampere (mA)
EQUATION 5-2:
R_PROG
=
10^
(log(I_REG)/(-0.93))log
1104
Where:
R_PROG = kilo-ohms (k)
I_REG = milliampere (mA)
Table 5-1 provides commonly seen E96 (1%) and E24
(5%) resistors for various charge current to reduce
design time.
TABLE 5-1: RESISTOR LOOK-UP TABLE
Charge Recommended Recommended
Current (mA) E96 Resistor () E24 Resistor ()
130
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
950
1000
1100
10k
8.45k
6.20k
4.99k
4.02k
3.40k
3.00k
2.61k
2.32k
2.10k
1.91k
1.78k
1.62k
1.50k
1.40k
1.33k
1.24k
1.18k
1.10k
1.00k
10k
8.20k
6.20k
5.10k
3.90k
3.30k
3.00k
2.70k
2.37k
2.20k
2.00k
1.80k
1.60k
1.50k
1.50k
1.30k
1.20k
1.20k
1.10k
1.00k
Constant-Current mode is maintained until the voltage
at the V_BAT pin reaches the regulation voltage, V_REG.
When Constant-Current mode is invoked, the internal
timer is reset.
5.5.1
TIMER EXPIRED DURING
CONSTANT CURRENT – FAST
CHARGE MODE
If the internal timer expires before the recharge voltage
threshold is reached, a timer fault is indicated and the
charge cycle terminates. The MCP73113/4 device
remains in this condition until the battery is removed. If
the battery is removed or input power is cycled, the
MCP73113/4 device enters the Standby mode where it
remains until a battery is reinserted.
5.6 Constant-Voltage Mode
When the voltage at the V_BAT pin reaches the
regulation voltage, V_REG, constant voltage regulation
begins. The regulation voltage is factory set to 4.10V,
4.20V, 4.35V or 4.40V with a tolerance of ±0.5%.
5.7 Charge Termination
The charge cycle is terminated when, during Constant-
Voltage mode, the average charge current diminishes
below a threshold established with the value of 5%,
7.5%, 10% or 20% of fast charge current or internal
timer has expired. A 1 ms filter time on the termination
comparator ensures that transient load conditions do
not result in premature charge cycle termination. The
timer period is factory set and can be disabled. Refer to
Section 1.0 “Electrical Characteristics” for timer
period options.
5.8 Automatic Recharge
The MCP73113/4 device continuously monitors the
voltage at the V_BAT pin in the Charge Complete mode.
If the voltage drops below the recharge threshold,
another charge cycle begins and current is once again
supplied to the battery or load. The recharge threshold
is factory set. Refer to Section 1.0 “Electrical
Characteristics” for recharge threshold options.
Note: The MCP73113/4 also offer options with
no automatic recharge.
For the MCP73113/4 devices with no recharge option,
the MCP73113/4 will go into Standby mode when
termination condition is met. The charge will not restart
until at least one of the following conditions have been
met:
• Battery is removed from the system and inserted
again
• V_DD is removed and plugged in again
• R_PROG is disconnected (or high-impedance) and
reconnected
DS22183D-page 18
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