High

Frequency

Current

Path

L1

R1

C3

C1

VBUS

PMID

C2

PGND

SW

V

BAT

BAT

VIN

ChargeCurrentDirection

ToCSINandCSOUTpin

R

SNS

ToInductor

ToCapacitorandbattery

CurrentSensingDirection

4.7uF

1uF

Vin+

Vin-

VBUS

4.7uF

1uF

Vin+

Vin-

VBUS

bq24155

www.ti.com

SLUS942 – FEBRUARY 2010

•

Place 4.7uF input capacitor as close to PMID pin and PGND pin as possible to make high frequency current

loop area as small as possible. Place 1uF input capacitor as close to VBUS pin and PGND pin as possible to

make high frequency current loop area as small as possible (see Figure 25).

Figure 23. High Frequency Current Path

Figure 24. Sensing Resistor PCB Layout

Figure 25. Input Capacitor Position and PCB Layout Example

Copyright © 2010, Texas Instruments Incorporated

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