1

FEATURES

APPLICATIONS

DESCRIPTION

ACP

PVCC

ACDET

ACSET

DPMDET

CELLS

SRP

SRN

BAT

CHGEN

ACN

SRSET

1

24

2

3

18

5

6

4

17

16

15

14

13

23

22

21

20

7

8

9

10

11

12

19

bq24705

QFN-24

TOP VIEW

bq24705

600-kHz, Host-Controlled Multi-Cell Battery Charger With Input Overvoltage Protection

• Notebook and Ultra-Mobile Computers

2

• NMOS-NMOS Synchronous Buck Converter

with 600 kHz Frequency and >95% Efficiency

• Portable Data-Capture Terminals

• Portable Printers

• 30-ns Minimum Driver Dead-time and 99.5%

Maximum Effective Duty Cycle

• Medical Diagnostics Equipment

• Battery Bay Chargers

• High-Accuracy Voltage and Current Regulation

• Battery Back-Up Systems

–

±0.5% Charge Voltage Accuracy

–

±3% Charge Current Accuracy

–

±3% Adapter Current Accuracy

The

bq24705

is

a

high-efficiency,

synchronous

–

±2% Input Current Sense Amp Accuracy

battery

charger

with

integrated

compensation,

• Integration

offering

low

component

count

for

space-limited

–

Internal Loop Compensation

multi-chemistry battery charging applications. Charge

current

and

voltage

programming

allows

high

–

Internal Soft-Start

regulation accuracies, and can be either hardwired

• Safety

with

resistors,

or

programmed

by

the

system

–

Input Overvoltage Protection (OVP)

power-management microcontroller using a DAC or

GPIOs.

–

Dynamic Power Management (DPM) with

Status Indicator

The bq24705 charges two, three, or four series Li+

cells, supporting up to 8 A of charge current, and is

• Supports Two, Three, or Four Li+ Cells

available in a 24-pin, 4x4-mm thin QFN package.

• 5 – 24 V AC/DC-Adapter Operating Range

• Analog Inputs with Ratiometric Programming

via Resistors or DAC/GPIO Host Control

–

Charge Voltage (4-4.512 V/cell)

–

Charge Current (up to 8 A, with 10-m

Ω

Sense Resistor)

–

Adapter Current Limit (DPM)

• Status and Monitoring Outputs

–

AC/DC Adapter Present with Programmable

Voltage Threshold

–

DPM Loop Active (DPMDET)

–

Current Drawn from Input Source

• Supports Any Battery Chemistry: Li+, NiCd,

NiMH, Lead Acid, etc.

• Charge Enable

• 10-µA Off-State Battery Current

Figure 1. bq24705, 24 LD QFN, Top View

• 24-pin, 4x4-mm QFN Package

1

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas

Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2

PowerPad is a trademark of Texas Instruments.

PRODUCTION DATA information is current as of publication date.

Copyright © 2007–2009, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Not Recommended for New Designs