Application schematics

STw4102

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5

Application schematics

5.1

Charge from USB or wall adapter

The MAIN input is used with either a wall adapter or a USB charger. The charge current can

be programmed to 100 mA or 500 mA max for use with a USB 2.0 port, or programmed to

The USBPWR input is used only for charging from a USB port (100 mA or 500 mA max).

Figure 16.

Charge using internal power devices

Table 8.

External component list

Name

Typ. value

Tolerance

Comments

12k to 120k

1%

Main charge current setting

30m

Ω

1%

Gas gauge sense resistor

C1

1µF

Internal supply decoupling capacitor

C2

1µF

Internal voltage reference decoupling capacitor

C3

0.1 to 22µF

When the battery is removed, a capacitor of at least

15µF is required for low ripple on the battery line.

C4

0.1 to 1µF

MAIN input decoupling capacitor

C5

0.1 to 1µF

USBPWR input decoupling capacitor

Indicator LED

to power

battery voltage

IO voltage

32kHz

Rset

C1

Rcg

STw4102

Reset

StandBy

C2

VOUT

SENSE

BATT

BATTSENSE

ISET

CVIS

C32KHZ

STDBY

ICG+

ICG-

GND

RESETN

SDA

SCL

VIO

LDOFB

LDODRV

CVREF

EOCHG

PWRDETECTN

MAIN

USBPWR

DRIVER

C3

management

from wall adapter

or USB port/charger

from USB port only

C5

C4

TEST