MCP73871-2CCISLASHML datasheet(18/40 Pages) MICROCHIP

18 / 40 page

MCP73871

DS20002090C-page 18

 2008-2013 Microchip Technology Inc.

The voltage divider equation is shown below:

EQUATION 3-1:

The calculated R1 equals 337.2 k when 110 k is

selected for R2. The 330 k resistor is selected for R1

to build the voltage divider for VPCC.

FIGURE 3-1:

Voltage Divider Example.

3.4

Input Source Type Selection (SEL)

The input source type selection (SEL) pin is used to

select input power source for input current limit control

feature. With the SEL input High, the MCP73871

device is capable of providing 1.65 (typical) total

amperes to be shared by the system load and Li-Ion

battery charging. The MCP73871 device limits the

input current up to 1.8A. When SEL active Low, the

input source is designed to provide system power and

Li-Ion battery charging from a USB Port input while

adhering to the current limits governed by the USB

specification.

3.5

Battery Management 0V Reference

(VSS)

Connect to negative terminal of the battery, system

load and input supply.

3.6

Battery Charge Control Output

(VBAT)

Connect to positive terminal of the Li-Ion/Li-Polymer

battery. Bypass to VSS with a minimum of 4.7 μF to

ensure loop stability when the battery is disconnected.

3.7

Battery Voltage Sense

(VBAT_SENSE)

Connect to positive terminal of battery. A precision

internal voltage sense regulates the final voltage on

this pin to VREG.

3.8

Charge Current Regulation Set

(PROG1)

The maximum constant charge current is set by placing

a resistor from PROG1 to VSS. PROG1 sets the

maximum constant charge current for both AC-DC

adapter and USB port. However, the actual charge

current is based on the input source type and the

system load requirement.

3.9

USB-Port Current Regulation Set

(PROG2)

The MCP73871 device USB-Port current regulation set

input (PROG2) is a digital input selection. A logic Low

selects a one unit load input current from the USB port

(100 mA) while a logic High selects a five unit load input

current from the USB port (500 mA).

3.10

Charge Status Output 1 (STAT1)

STAT1 is an open-drain logic output for connection to

an LED for charge status indication. Alternatively, a

pull-up resistor can be applied for interfacing to a host

microcontroller. Refer to Table 5-1 for a summary of the

status output during a charge cycle.

3.11

Charge Status Output 2 (STAT2)

STAT2 is an open-drain logic output for connection to

an LED for charge status indication. Alternatively, a

pull-up resistor can be applied for interfacing to a host

microcontroller. Refer to Table 5-1 for a summary of the

status output during a charge cycle.

3.12

Power-Good (PG)

The power-good (PG) is an open-drain logic output for

input power supply indication. The PG output is low

whenever the input to the MCP73871 device is above

the UVLO threshold and greater than the battery

voltage. The PG output may be used with an LED or as

an interface to a host microcontroller to signal when an

input power source is supplying power to the system

and the battery. Refer to Table 5-1 for a summary of the

status output during a charge cycle.

V VPCC

R1 R2

-------------------



 V

1.23V



1.23V

110k



110k

 R

------------------------------



 5V



337.2k



330 k



110 k



VIN

VPCC

MCP73871-2CCI/ML Scheda tecnica(PDF) 18 Page - Microchip Technology

MCP73871-2CCI/ML Scheda tecnica(HTML) 18 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Scheda tecnica Scarica

Link URL