MCP6271R Microchip Technology Inc., MCP6271R Datasheet - Page 11

• Manufacturer Part Number: MCP6271R
• Description: 170 ?a, 2 Mhz Rail-to-rail Op Amp
• Manufacturer: Microchip Technology Inc.

When the battery voltage falls below a recharge threshold, the
MCP7384X products automatically initiate a new charge cycle.
This allows the battery to be kept at near-full charge at all times,
making it readily available for utilization at any point of time. The
operation also allows for higher reliability, since “trickle-charging”
Li-Ion batteries for extended periods results in life degradation.
The number of available portable equipment types are expected
to increase in the years to come. Extending usable battery life
and reducing charge-cycle time are essential for ensuring a
positive user experience. Battery manufacturers are already
offering new, space-saving Li-Ion battery packs with high capacity
to meet today’s power demands. While high-capacity batteries
are able to extend operating life, they also introduce significant
design challenges. Addressing both issues requires accurate
voltage regulation and the utilization of external-pass transistors
that are capable of providing high charge current while ensuring
thermal stability.
Figure 1: Typical Charging Circuit for High-Capacity Battery Packs.
Figure 2: Battery Capacity vs. Charging Voltage.
Charging Lithium Batteries
1750
1700
1650
1600
1550
1500
1450
4.2000
Voltage
Regulated
Wall Cube
4.1875
Charging Voltage (V)
4.1750
*Optional
Reverse
Blocking
Diode
4.1625
R
T2
4.1500
R
R
T1
SENSE
SENSE
V
STAT1
EN
THREF
DD
Figure 3: Battery Capacity Loss vs. Under-Charge Voltage.
10%
9%
8%
7%
6%
5%
4%
3%
2%
1%
0%
0.0%
Analog and Interface Guide – Volume 2
DRV
V
V
TIMER
THERM
BAT
SS
0.2%
Q1
Under-Charge Voltage (%)
0.4%
C
TIMER
0.6%
Battery
Pack
0.8%
+
–
1.0%
1.2%
9