Texas Instruments bq2404 series User Manual

User's Guide

SLUUA77–January 2013

1-A Single-Input, Single-Cell Li-Ion Battery Charger

This user’s guide describes the bq2404x evaluation module (EVM), how to perform a stand-alone evaluation or interface with a host or system. The charger is designed to deliver up to 1000 mA of continuous current to the battery output when programmed with a resistor on the ISET pin and is programmed at the factory for ~540 mA. The USB current limit modes are selected by the ISET2 pin and limits current to a maximum of 500 mA (logic high) or 100 mA (float or high impedance). A low on the ISET2 pin programs the charge current using the ISET resistor.

Contents

1 Introduction .................................................................................................................. 2

2 Considerations With Evaluating the bq2404x ........................................................................... 2

3 Performance Specification Summary ..................................................................................... 2

4 Test Procedure Summary .................................................................................................. 3

4.1 Equipment ........................................................................................................... 3

4.2 Equipment Setup ................................................................................................... 3

4.3 Jumper Setup ....................................................................................................... 4

4.4 ISET, PRETERM, and TS Setup ................................................................................. 4

4.5 Procedure ........................................................................................................... 5

5 Schematic, Physical Layouts and Bill of Materials ..................................................................... 6

5.1 Schematic ........................................................................................................... 6

5.2 Physical Layouts ................................................................................................... 7

5.3 Bill of Materials ..................................................................................................... 9

List of Figures

1 Original Test Setup ........................................................................................................ 3

2 Battery Emulator ........................................................................................................... 4

3 bq2404x EVM Board Schematic.......................................................................................... 6

4 bq2404x EVM Assembly Layer ........................................................................................... 7

5 bq2404x EVM Top Layer .................................................................................................. 7

6 bq2404x EVM Bottom Layer............................................................................................... 8

SLUUA77–January 2013 1-A Single-Input, Single-Cell Li-Ion Battery Charger

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Introduction

1 Introduction

The bq2404x series of devices are highly integrated Li-ion linear charger devices targeted at space-limited portable applications. The devices operate from either a USB port or AC adapter.

The bq2404x has a single power output that charges the battery. A system load can be placed in parallel with the battery as long as the average system load does not keep the battery from charging fully during the 10 hour safety timer.

The battery is charged in three phases: conditioning, constant current, and constant voltage. In all charge phases, an internal control loop monitors the IC junction temperature and reduces the charge current if an internal temperature threshold is exceeded.

The charger power stage and charge current sense functions are fully integrated. The charger function has high-accuracy current and voltage regulation loops, charge status display, and charge termination. The pre-charge current and termination current threshold are programmed via an external resistor on the bq24040 and bq24045. The fast charge current value is also programmable via an external resistor.

2 Considerations With Evaluating the bq2404x

Refer to the data sheet for specific details on the charger ICs. The main differences between the bq24040 and the bq24041 are that the Pre-Term pin is replaced with an Auto Start (I/O) (ASI/ASO) feature, a different Over-Voltage Protection Threshold, and a Temperature Sense Pin (TS) versus a BAT_EN pin. The main difference between the bq24040 and bq24045 is in the regulation voltage. The bq24040 is 4.2-V and bq24045 is 4.35-V regulation voltage.

The ISET current control loop sets the maximum charge current. This maximum programmed current level can be further reduced by entering a USB mode, selected by the ISET2 pin.

The ASO output is dependent on the OUT pin to power the internal OR gate along with at least one high signal on the input (bq24041).

A system load may be connected to the OUT pin, which takes away some of the charge current. Normally it is not recommended to operate the device in pre-charge since the system load keeps the battery from recovering; but, since the PRE_TERM pin can program a higher pre-charge current this restriction is not necessary.

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3 Performance Specification Summary

Specification Test Conditions MIN TYP MAX UNIT

Input DC voltage, V Reduced Performance,

Power Dissipation

(3)

OUT

(1)

Input voltage range is specified for normal operation. Input voltage between UVLO and 4.75 V has limited functionality, but does not damage the IC nor present any safety issue with the battery. Input voltage above OVP and less than 30 Vdc has no operation and will not damage the IC. Lower input voltage (closer to dropout operation) produces less heat dissipation and potentially better performance.

(2)

The junction temperature rise above ambient is proportional to the power dissipation. Once the junction temperature reaches ~125°C, thermal regulations reduces the programmed charge current.

(3)

The EVM is set for 800 mA, by changing R1 to lower values, it can support up to 1000 mA.

(1)

(2)

Recommended input voltage range 4.45 6.45 V Will not charge with Over Voltage input condition. Limited 3.5 28 V

charging with under voltage input. P

= (VIN– V

DISS

RISET = 1 kΩ 0.54 0.8 A

OUT

) × I

OUT

1.5 W

1-A Single-Input, Single-Cell Li-Ion Battery Charger SLUUA77–January 2013

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PS1

VM2

VM1

PS2

Battery

Emulator

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4 Test Procedure Summary

4.1 Equipment

The following sections outline the equipment necessary to perform all tests in the test procedure.

• Power supply #1 (PS #1) capable of supplying 12 V at 3 A is required

• Power supply #2 (PS #2) capable of supplying up to 5 V at 5 A is required to power battery emulator.

• PR1010-002 (Battery emulator)

• Flat-head screwdriver

• Three voltage meters (VM) and two equivalent current meters (A) are required. The current meters must be able to measure 3-A current.

4.2 Equipment Setup

1. For all power connections, use short, twisted-pair wires of appropriate gauge wire for the amount of the current (can handle 3 A).

2. Set PS1 for 5-V, 2-A current limit and then turn off supply

3. Connect the PS1 in series with current meter (A1) to J1 (DC+ and DC–).

4. Connect a Voltmeter (VM1) across DC1 and DC2.

5. Adjust PS2 set to approximately 3.6 V with current limit of 4 A to the input side of battery emulator, then turn off PS2.

6. Connect VM2 across J2 (OUT, GND)

7. Connect the output side of the battery emulator in series with current meter (A2) to J2 (OUT and GND).

See Figure 1 and Figure 2 as Reference.

Test Procedure Summary

SLUUA77–January 2013 1-A Single-Input, Single-Cell Li-Ion Battery Charger

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Figure 1. Original Test Setup

BAT+ BAT±

1 2

BAT+

BAT±

P/S+

GND

2 1

PS#2 + PS#2 ±

1N5821

P/S Range: 0 to 4.5 V, 3 A max Current due to 1N5821 CONNECT TO POWER SOURCE

Battery Range: 0 to 4.3 V, Sink up to 4.5 V/(2.2 /2)=4.0 A max CONNECT TO CHARGER BAT+ TO BAT±

2.2, 25 W

1 2

0.1, 2 W± 5 W

Metal Strip Sense Resistor 15FR100E

TBH25P5R6

Test Procedure Summary

4.3 Jumper Setup

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Figure 2. Battery Emulator

JMP1→Installed JMP2→ Installed JMP3→ISET2 and GND shorted JMP4→ Installed JMP5→ Installed

4.4 ISET, PRETERM, and TS Setup

4.4.1 TS

• Use the VM3 to measure the Resistance across GND and TP9

• Adjust R11 until VM3 reads 10 kΩ ±500 Ω

4.4.2 ISET

• Use the VM3 to measure the Resistance across GND and TP2

• Adjust R2 until VM3 reads 1 kΩ ±50 Ω

4.4.3 PRETERM

• Use the VM3 to measure the Resistance across GND and TP4

• Adjust R4 until VM3 reads 2 kΩ ±100Ω

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4.5 Procedure

4.5.1 Operational Testing

1. Ensure that the recommended test setup is followed

2. Turn ON PS1 and PS2

3. Adjust PS2 such that VM2 reads 3.6 V ±50mV

4. Adjust PS1 such that VM1 reads 5 V ±50mV

5. Measure on A#2 → I

6. Make sure D1 and D2 are ON

7. Remove the shorting jumper on JMP3

8. Measure on A#2 → I

9. Make sure D1 and D2 are ON

10. Short ISET2 to HI on JMP3

11. Measure on A#2 → I

12. Make sure D1 and D2 are ON

13. Put shorting jumper back on JMP3 between ISET2 and GND

14. Using VM3, measure the voltage between TP9 (TS pin) and GND

15. Adjust R11 until VM3 reads 0.9 V±50 mV

16. Measure on A#2 → I

17. Adjust R11 until VM3 reads 1.3 V±50 mV

18. Measure on A#2 → I

19. Measure on A#1 → IIN= 0 mA ±50 mA

20. Adjust back R11 until VM3 reads 0.5 V±50 mV

21. Measure on A#2 → I

22. Measure on A#1 → IIN= 580 mA ±70 mA

23. Increase PS2 until VM2 reads 4.30 V (4.2 V for bq24040)

24. Then slowly increase PS2 until D2 turns OFF

25. Measure on A#2 → I

26. Measure on A#1 → IIN= 0 mA ±50 mA

27. Decrease PS2 until VM2 reads 3.6 V±10 mV

28. Measure on A#2 → I

29. Measure on A#1 → IIN= 580 mA ±70 mA

30. Turn PS1 and PS2 off

31. Remove all test equipment from the UUT

= 540 mA ±50 mA

CHRG

= 100 mA ±50 mA

CHRG

= 500 mA ±60 mA

CHRG

= 270 mA ±50 mA

CHRG

= 0 mA ±20 mA

CHRG

= 540 mA ±50 mA

CHRG

= 0 mA ±20 mA

CHRG

= 540 mA ±50 mA

CHRG

Test Procedure Summary

SLUUA77–January 2013 1-A Single-Input, Single-Cell Li-Ion Battery Charger

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Texas Instruments bq2404 series User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual