1

SMBus Interfaced Battery Charger with Internal FETs

ISL95871C

The ISL95871C is a highly integrated Lithium-ion battery charger

controller, programmable over the System Management Bus

(SMBus) with internal switching FETs. High efficiency is achieved

with a DC/DC synchronous-rectifier buck converter, equipped with

diode emulation for enhanced light load efficiency and system bus

boosting prevention. The ISL95871C charges one to four

Lithium-ion series cells, and delivers up to 8A charge current.

Integrated MOSFETs and bootstrap diode result in fewer

components and smaller implementation area. Low offset

current-sense amplifiers provide high accuracy with 10m

Ω sense

resistors. The ISL95871C provides 0.5% battery voltage accuracy.

The ISL95871C also provides a digital output that indicates the

presence of the AC-adapter as well as an analog output which

indicates the adapter current within 4% accuracy.

Applications

• Notebook Computers

• Tablet PCs

• Portable Equipment with Rechargeable Batteries

Features

• Internal Synchronous Buck Output Stage Power FETs

• 0.5% Battery Voltage Accuracy

• 3% Adapter Current Limit Accuracy

• 3% Charge Current Accuracy

• SMBus 2-Wire Serial Interface

• Battery Short Circuit Protection

• Fast Response for Pulse-Charging

• Fast System-Load Transient Response

• Monitor Outputs

- Adapter Current (3% Accuracy)

- AC-Adapter Detection

• 11-Bit Battery Voltage Setting

• 6 Bit Charge Current/Adapter Current Setting

• 8A Maximum Battery Charger Current

• 11A Maximum Adapter Current

• +8V to +22V Adapter Voltage Range

• Pb-Free (RoHS Compliant)

Related Literature

• See AN1590, ISL95871C Evaluation Board User Guide

FIGURE 1. EFFICIENCY vs CHARGE CURRENT AND BATTERY

VOLTAGE (EFFICIENCY DCIN = 20V)

FIGURE 2. DERATING CURVE WITH NATURAL AIR FLOW

(MEASURED ON 10cm x 10cm EVALUATION BOARD)

60

65

70

75

80

85

90

95

100

02

3

4

6

8

CHARGE CURRENT (A)

15

7

1 CELL

2 CELL

4 CELL

3 CELL

0

1

2

3

4

5

6

7

8

9

0

25

50

75

100

125

150

AMBIENT TEMPERATURE (°C)

1 CELL

2 CELL

4 CELL

3 CELL

June 8, 2011

FN6856.2

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

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