Microchip Technology MCP73871DM-VPCC User Manual

DS51812B-page 10

© 2009 Microchip Technology Inc.

The MCP73871 Demo Board with Voltage Proportional Current Control demonstrates 
the features of Microchip’s MCP73871 “Stand-Alone System Load Sharing and Li-Ion 
/ Li-Poly Battery Charge Management Controller”.The MCP73871 Demo Board with 
Voltage Proportional Current Control is designed to deliver minimum 1.5A total current 
to system load and to a single cell Li-Ion battery at 4.2V preset voltage regulation (4.1V, 
4.35V and 4.4V options are also available for MCP73871). The MCP73871 Demo 
Board with Voltage Proportional Current Control has one dip switch (S1) with four poles 
to control input current limits, enable charge timer and enable charging. The first switch 
decides the input power source between AC-DC wall adapter and USB port (AC/USB). 
The second switch of S1 determines the 500 mA high-power USB port or the 100 mA 
low-power USB port (High/Low), if the first switch of S1 is enabled (ON). The input 
current limit is governed by the USB specification when selecting USB on S1 switch.
The maximum fast current when AC is selected on S1 is programmed by the resistor 
R

PROG1

 at 1A, and the termination current is set at 100 mA by R

PROG3

 

(see Figure 1-1).
The MCP73871 Demo Board with Voltage Proportional Current Control offers three 
status LED (for charge status outputs and a power-good indicator).

The MCP73871 Demo Board with Voltage Proportional Current Control comes with a 
factory preset low-battery indicator (LBO) when input is absent. The preset value is 
3.2V and STAT1 LED (Green) will turn ON if the battery voltage is below the threshold 
voltage.
The MCP73871 Demo Board with Voltage Proportional Current Control is designed to 
cover all the features of the MCP73871 device. A thermistor can be added at test points 
TP6 and TP7, but resistor R6 must be removed (see the A.2 “Board – Schematic”). 
The board layout easily permit to change the two programmable resistors: R

PROG1 

and 

R

PROG3

.

This MCP73871 Demo Board with Voltage Proportional Current Control kit includes:
• One MCP73871 Demo Board with Voltage Proportional Current Control, 

102-00244

• Important Information "Read First"

Note: Refer to Table 2-1

 

for charge status outputs and Figure 2-1 for charge 

current setups.