IN

VBUS

GND

HOST

bq25100

OUT

1ÛF

1ÛF

SYSTEM

D+

D-

USB Port or

Adapter

ISET

PRETERM

TEMP

PACK+

PACK-

TS

VSS

CE

3.4k

Ÿ

6k

Ÿ

2.7k

Ÿ

10 nF

Optional

RC

bq25100, bq25101, bq25100A, bq25100H, bq25101H, bq25100L

SLUSBV8C – AUGUST 2014 – REVISED NOVEMBER 2014

www.ti.com

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

9.1 Application Information

The bq2510x series of devices are highly integrated Li-Ion and Li-Pol linear chargers targeted at space-limited

portable applications. The fast charge current can be programmed from 10 mA to 250 mA through an external

resistor on ISET pin. The pre_charge and termination current can also be programmed through the resistor

connected on PRETERM pin. The device has complete system-level protection such as input under-voltage

lockout (UVLO), input over-voltage protection (OVP), sleep mode, thermal regulation, safety timers, and NTC

monitoring input.

9.2 Typical Application - Charger Application Design Example

9.2.1 Design Requirements

•

Supply voltage = 5 V

•

Fast charge current: IOUT-FC = 40 mA;

•

Termination Current Threshold: %IOUT-FC = 10% of Fast Charge or ~4 mA

•

Pre-Charge Current by default is twice the termination Current or ~8 mA

•

TS – Battery Temperature Sense = 10-k NTC (103AT)

•

/CE is an open drain control pin

9.2.2 Detailed Design Procedures

•

The regulation voltage is set to 4.2 V, the input voltage is 5 V and the charge current is programmed to 40

mA.

•

For charge current that is below 50 mA, an extra RC circuit is recommended on ISET to acheive more stable

current signal. For applications that need higher charge current, the RC circuit is not needed.

•

For applications that use more than 200-mA current, there could be a very low level ~1% of charge current

ringing in the output. The ringing can be removed by increasing the input capacitance.

22

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Product Folder Links: bq25100 bq25101 bq25100A bq25100H bq25101H bq25100L