MCP73871-2CCI/SS Microchip Technology, MCP73871-2CCI/SS Datasheet - Page 19

• Manufacturer Part Number: MCP73871-2CCI/SS
• Description: USB/AC Battery Charger With Power Path Management 20 SSOP .209in TUBE
• Manufacturer: Microchip Technology

Specifications of MCP73871-2CCI/SS

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

4.12
If the voltage on the IN pin drops to a preset value,
determined by the threshold established at the VPCC
input, due to a limited amount of input current or input
source impedance, then the battery charging current is
reduced. The VPCC control tries to reach a steady-
state condition where the system load has priority and
the battery is charged with the remaining current.
Therefore, if the system demands more current than
the input can provide, the ideal diode will become
forward biased and the battery is able to supplement
the input current to the system load.
The VPCC sustains the system load as its highest
priority. It does this by reducing the noncritical charge
current while maintaining the maximum power output of
the adapter. Further demand from the system is sup-
ported by the battery, if possible.
The VPCC feature functions identically for USB port or
ac-dc adapter inputs. This feature can be disabled by
connecting the VPCC to IN pin.
© 2008 Microchip Technology Inc.
VOLTAGE PROPORTIONAL
CHARGE CONTROL (VPCC)
4.13
If the input current threshold is reached, then the
battery charging current is reduced. The ICLC tries to
reach a steady-state condition where the system load
has priority and the battery is charged with the remain-
ing current. No active control limits the current to the
system. Therefore, if the system demands more
current than the input can provide or the input ICLC is
reached, the ideal diode will become forward biased
and the battery is able to supplement the input current
to the system load.
The ICLC sustains the system load as its highest
priority. This is done by reducing the non-critical charge
current while adhering to the current limits governed by
the USB specification or the maximum ac-dc adapter
current supported. Further demand from the system is
supported by the battery, if possible.
FIGURE 4-4:
USB Port.
-100
-200
700
600
500
400
300
200
100
0
INPUT CURRENT LIMIT CONTROL
(ICLC)
0
100 200 300 400 500 600 700
Load Current (mA)
Input Current Limit Control -
MCP73871
DS22090A-page 19
Ideal
Diode
Input Current
Battery Current
Load Current