Texas Instruments bq24720 EVM, bq24721 EVM User Manual

User's Guide

SLUU237 – January 2006

bq24720/21 EVM (HPA104) for Multi-Cell Synchronous

Switch-Mode Charger With System Power Selector and

SMBus SBS-Like Interface

Contents

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

2 Test Summary ...................................................................................... 4

3 Circuit Design and Layout Guideline ........................................................... 21

4 Bill of Materials, Board Layout, and Schematics .............................................. 22

List of Figures

1 Connections of the EV2300 Kit ................................................................... 5

2 Original Test Setup for bq24720 EVM ........................................................... 6

3 Original Test Setup for bq24721 EVM ........................................................... 7

4 The Main Window of the bq2472x SMB Evaluation Software ................................ 8

5 The Software Main Window ....................................................................... 9

6 The Software Main Window ..................................................................... 10

7 The Software Main Window ..................................................................... 11

8 The Waveforms at No Load ..................................................................... 12

9 Test Setup for bq24720 EVM .................................................................... 13

10 Test Setup for bq24721 EVM .................................................................... 13

11 The Software Main Window ..................................................................... 14

12 The Waveforms at I

13 The Software Main Window ..................................................................... 16

14 The Software Main Window ..................................................................... 17

15 The Waveforms at I

16 The Software Main Window ..................................................................... 19

17 The Software Main Window ..................................................................... 20

18 Top Assembly ..................................................................................... 24

19 Bottom Assembly .................................................................................. 25

20 Layer 1.............................................................................................. 26

21 Layer 2.............................................................................................. 27

22 Layer 3.............................................................................................. 28

23 Layer 4.............................................................................................. 29

24 Top Silk ............................................................................................. 30

= 3 A .................................................................... 15

(bat)

= 300 mA ............................................................... 18

(bat)

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Introduction

1 Introduction

1.1 EVM Features

1.2 General Description

• Evaluation Module For Both bq24720 and bq24721

• High Efficiency NMOS-NMOS Synchronous Buck Charger With User-Selectable 300 kHz or 500 kHz

Frequency

• Battery/Adapter to System Power Selector Function

• SBS-Like SMBus Interface for Control and Status Communications With Host

• Programmable Battery Voltage, Charge Current, and AC Adapter Current via SBS-Like SMBus

Interface

• Battery Pack Voltage Regulation Range up to 19.2 V

• AC Adapter Operating Range 13 V–24 V

• Charge and Adapter Overcurrent Protection

• Charge Peak Current up to 14 A. Charge Average Current up to 7 A

• LED Indication for AC Adaptor Connection, Power Path Conduction, Charge Enable and Alarm Signal

• Test Points for Key Signals Available for Testing Purpose. Easy Probe Hook-up

• Jumpers Available. Easy to Change Connections and Enable (or Disable) Charge

• May Be Used with TI bq2472x SMB Evaluation Software

The bq24720/21 evaluation module is a complete charger module for evaluating a multi-cell synchronous notebook charge and path selection solution using the bq24720/21 devices. It is designed to deliver up to 9 A of charge current to Li-Ion or Li-Pol applications.

The bq24720/21 has a highly integrated battery charge controller designed to work with external host commands. The battery voltage, charge current, and other system parameters are programmable via SBS-like SMBus interface.

The dynamic power management (DPM) function SMBus Interface modifies the charge current depending on system load conditions, avoiding ac adapter overload.

High accuracy current sense amplifiers enable accurate measurement of either the charge current or the ac adapter current, allowing termination of nonsmart packs and monitoring of overall system power.

The adapter isolation diode can be bypassed with external an MOSFET using a control signal provided by the bq24720/21, thus reducing overall power dissipation.

For details, see the bq24720 data sheet (SLUS668 ) and the bq24721 data sheet (SLUS683 ).

1.3 I/O Description

Jack Description

J1–POS AC adapter, positive output J1–GND AC adapter, negative output J2–POS External power supply, positive output J2–GND External power supply, negative output J3–REF VREF5 pin (11) output J3–CHGEN CHGEN pin (1) output J3–SDA SDA pin (13) output, SMBus data line J3–SCL SCL pin (14) output, SMBus clock line J4–ALARM ALARM pin (25) output J4–IOUT IOUT pin (17) output J4–GND Ground

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Jack Description

J5–REF IC reference voltage VREF5 (pin 11) J5–VPUP Pull-up voltage source J5–EXT External power supply J6–CHGEN CHGEN pin (1) output J6–GND Ground J7–VPUP Pull-up voltage source J7–LEDPWR LED Pull-up power line J8–ACGD/TS ACGOOD pin (15) output for bq24720, TS pin (15) output for bq24721 J8–GND Ground J8–VBAT Connected to battery pack J8–VSYS Connected to system J9–BYPASS BYPASS pin (6) output J9–LED LED drive J10–ACDRV ACDRV pin (2) output J10–LED LED drive J11–BATDRV BATDRV pin (24) output J11–LED LED drive J12–ACGD ACGOOD pin (15) output J12–LED LED drive

Introduction

1.4 Controls and Key Parameters Setting

Jack or Resistor Description Factory Setting

Pull-up power source setting

J5 1-2: Use external power supply as the pull-up source

2-3: Use REF5 as the pull-up source

J6 Enable charge process when ON. Off J7 On

The pull-up power source supplies the LEDs when ON. LED has no power source when OFF.

J9 The conduction of the bypass MOSFET is indicated by D8 when ON. On J10 The conduction of the AC MOSFET is indicated by D10 when ON. On J11 The conduction of the battery MOSFET is indicated by D11 when ON. On

1.5 Recommended Operating Conditions

SYMBOL DESCRIPTION MIN TYP MAX UNIT

V V I

(chrg)

Supply voltage Input voltage from ac adapter input 13 19.5 24 V

Battery voltage Voltage applied at VBAT terminal of J8 9–16.8 20 V

(BAT)

Supply current Maximum input current from ac adapter input 5 7 A Charge current Battery charge current 2 4 7 A Operating junction temperature range 0 125 ° C

1-2 (pin 1 and 2 are short-circuited)

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Switch-Mode Charger With System Power Selector and SMBus SBS-Like Interface

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Test Summary

2 Test Summary

2.1 Definitions

This procedure details the configure of the HPA104 evaluation board. On the test procedure, the following naming conventions are followed. See the HPA104 schematic for details.

VXXX : External voltage supply name (VADP, VBT, VSBT) LOADW: External load name (LOADR, LOADI) V(TPyyy): Voltage at HPA104 internal test point TPyyy. For example, V(TP12) means the

voltage at TP12. V(Jxx): Voltage at HPA104 jack terminal Jxx. V(TP(XXX)): Voltage at test point XXX. For example, V(ACDET) means the voltage at the

test point which is marked as ACDET. V(XXX, YYY): Voltage across point XXX and YYY. I(JXX(YYY)): Current going out from the YYY terminal of jack XX. Jxx(BBB): Terminal or pin BBB of jack xx Jxx ON : HPA104 internal jumper Jxx terminals are shorted Jxx OFF: HPA104 internal jumper Jxx terminals are open Jxx (-YY-) ON: HPA104 internal jumper Jxx adjacent terminals marked as YY are shorted Measure → A,B Check specified parameters A, B. If measured values are not within specified

limits, the unit under test has failed. Observe → A,B Observe if A, B occurs. If they do not occur, the unit under test has failed.

The assembly drawings have locations for jumpers, test points, and individual components.

2.2 Equipment

2.2.1 POWER SUPPLIES

• Power Supply Number 1 (PS1): a power supply capable of supplying 20-V at 5-A is required.

• Power Supply Number 2 (PS2): a power supply capable of supplying 5-V at 1-A is required.

• Power Supply Number 3 (PS3): a power supply capable of supplying 5-V at 1-A is required. (bq24721

EVM only).

2.2.2 ELECTRONIC LOAD

• A 30-V, 5-A electronic load

2.2.3 KEPCO LOAD

• A Kepco bipolar operational power supply / amplifier, 0 V ± 20 V (or above), 0 A ± 6 A (or above).

2.2.4 METERS

• Eight Fluke 75, (equivalent or better) – Or: Five equivalent voltage meters and three equivalent current meters. The current meters must

be able to measure 5A+ current.

2.2.5 OSCILLOSCOPES

• An oscilloscope, a single voltage probe, and a single current probe are required.

bq24720/21 EVM (HPA104) for Multi-Cell Synchronous4 SLUU237 – January 2006 Switch-Mode Charger With System Power Selector and SMBus SBS-Like Interface

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2003

EV2300

HPA002

VCC

HDQ

VOUT

GND

VOUT

SDA

SCL

GND

SMBD

SMBC

GND

HDQI2C

SMB

USB

To Computer

USB port

SDA

SCL

GND

To EVM

2003

EV2300

HPA002

VCC

HDQ

VOUT

GND

VOUT

SDA

SCL

GND

SMBD

SMBC

GND

HDQI2C

SMB

USB

To Computer

USB port

SDA

SCL

GND

To EVM

2.2.6 COMPUTER

• A computer with at least one USB port and a USB cable. The EV2300 USB driver and the bq2472x SMB evaluation software must be properly installed.

2.2.7 EV2300 SMBUS COMMUNICATION KIT

• An EV2300 SMBUS communication kit.

2.2.8 SOFTWARE

• Driver(USB EV2300) Installer XP2K-Last updated Jan 28-04.zip: This is the EV2300 USB driver. Save and unzip to c:\temp (or other directory). Double click on the setup.exe file. Follow the installation steps.

• bq24720SMBEVSW2_10.zip: This is the bq2472x SMB evaluation software. Save and unzip to c:\temp (or other directory). Double click on the SETUP.EXE file. Follow the installation steps. This software needs to be installed after the EV2300 USB driver.

2.3 Equipment Setup

1. Set the power supply number 1 for 0 V ± 100 mVDC, 5 A ± 0.1 A current limit and then turn off the supply.

2. Connect the output of power supply number 1 in series with a current meter (multimeter) to J1 (POS, GND).

3. Connect a voltage meter across J1 (POS, GND).

4. Set the power supply number 2 for 3.3 V ± 100 mVDC, 1 A ± 0.1 A current limit and then turn off the supply.

5. Connect the output of the power supply number 2 to J2 (POS, GND).

6. Set the Kepco load for 10 V ± 100 mVDC and then turn it off.

7. Turn off the electronic load.

8. Connect a voltage meter across J8 (VBAT, GND).

9. Connect a voltage meter across J8 (VSYS, GND).

10. Connect J3 (SDA, SCL) and J4 (GND) to the EV2300 kit SMB port. Connect the USB port of the EV2300 kit to the USB port of the computer. The connections are shown in Figure 1 .

Test Summary

SLUU237 – January 2006 bq24720/21 EVM (HPA104) for Multi-Cell Synchronous 5

11. Turn on the oscilloscope.

12. Insert the voltage probe into TP30 (PH) and connect it to the oscilloscope.

13. Hook up the current probe to the wire connected to L1, and connect to the oscilloscope. Set up the

Figure 1. Connections of the EV2300 Kit

current probe so that the current direction is from the floating pad to the pad on the right-hand side.

14. J5 (VPUP, EXT): ON, J6: OFF, J7: ON, J9: ON J10: ON, J11: ON.

15. J12: ON ( For bq24720 only), J12: OFF ( For bq24721 only).

Switch-Mode Charger With System Power Selector and SMBus SBS-Like Interface

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POS

GND

VSYS

GND

VBAT

IOUT

GND

REF

J11J10J9

Power

supply #2

ACGD

GND

ALARM

CHGEN

SDA

SCL

POS

D8 D10 D11 D7 D9

D18

J12

APPLICATION CIRCUIT

USB

EV2300

Iin

Power

supply #1

BQ24720 EVM

Oscilloscope

POS

GND

VSYS

GND

VBAT

IOUT

GND

REF

J11J10J9

J7J7J7

Power

supply #2

ACGD

GND

ALARM

CHGEN

SDA

SCL

POS

J6J6J6

D8 D10 D11 D7 D9

D18

J12

APPLICATION CIRCUIT

USB

EV2300

Iin

Power

supply #1

BQ24720 EVM

Oscilloscope

Test Summary

16. ( For bq24721 only) Set the power supply number 3 for 2.5 V ± 100 mVDC, 1 A ± 0.1 A current limit and then turn off the supply.

17. ( For bq24721 only) Connect the output of the power supply number 3 to J8 (ACGD, GND).

After the steps above, the test setup for bq24720 EVM is shown in Figure 2 . The test setup for bq24721 EVM is shown in Figure 3 .

Figure 2. Original Test Setup for bq24720 EVM

6 bq24720/21 EVM (HPA104) for Multi-Cell Synchronous SLUU237 – January 2006

Switch-Mode Charger With System Power Selector and SMBus SBS-Like Interface

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POS

GND

VSYS

GND

VBAT

IOUT

GND

REF

J11J10J9

Power

supply #2

ACGD

GND

ALARM

CHGEN

SDA

SCL

POS

D8 D10 D11 D7 D9

D18

J12

APPLICATION CIRCUIT

USB

EV2300

Iin

Power

supply #1

BQ24721 EVM

Oscilloscope

Power

supply #3

POS

GND

VSYS

GND

VBAT

IOUT

GND

REF

J11J10J9

J7J7J7

Power

supply #2

ACGD

GND

ALARM

CHGEN

SDA

SCL

POS

J6J6J6

D8 D10 D11 D7 D9

D18

J12

APPLICATION CIRCUIT

USB

EV2300

Iin

Power

supply #1

BQ24721 EVM

Oscilloscope

Power

supply #3

Test Summary

Figure 3. Original Test Setup for bq24721 EVM

Turn on the computer. Open the bq2472x SMB evaluation software. The main window of the software is shown in Figure 4 .

SLUU237 – January 2006 bq24720/21 EVM (HPA104) for Multi-Cell Synchronous 7

Switch-Mode Charger With System Power Selector and SMBus SBS-Like Interface

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Test Summary

Figure 4. The Main Window of the bq2472x SMB Evaluation Software

2.4 Procedure

2.4.1 AC Adapter Detection Threshold

Make sure EQUIPMENT SETUP steps are followed. Turn on PS2 ( For bq24721 only) Turn on PS3 Turn on PS1

Measure→ V(J8(VSYS)) = 0 V ± 500 mV Measure→ V(TP(VREF5)) = 0 V ± 500 mV

Increase the output voltage of PS1 until the D8 (BYPASS) is on. The threshold is approximately 13 V. Do not exceed.

Measure→ V(TP(ACDET)) = 1.2 V ± 0.1 V Measure→ V(J1(POS)) = 13 V ± 1 V Measure→ V(J8(VSYS)) = 13 V ± 1 V Measure→ V(TP(VREF5)) = 5 V ± 500 mV Measure→ V(TP20) = 6 V ± 200 mV (TP20 is a through-hole test point above the IC) Observe→ D18 (ACGOOD) on ( for bq24720 only) Observe→ D10 (ACSW) ON, D9 (ALARM) ON

bq24720/21 EVM (HPA104) for Multi-Cell Synchronous8 SLUU237 – January 2006 Switch-Mode Charger With System Power Selector and SMBus SBS-Like Interface

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2.4.2 Charge Parameters Setting

Increase the voltage of PS1 until V(J1(POS)) = 19 V ± 0.1 V.

Measure→ V(J8(VBAT, GND)) = 0 V ± 1 V

In the software main window, click Read All on the top part of the window. The window is shown in

Figure 5 .

Test Summary

Figure 5. The Software Main Window

Type 12600 (mV) in the Battery Voltage Register on the lower right part of the window and click Write. This sets the battery voltage regulation threshold.

Type 1000 (mA) in the Charge Current Register on the lower right part of the window and click Write. This sets the battery charge current regulation threshold.

Type 5000 (mA) in the Input Current Register on the lower right part of the window and click Write. This sets the input current regulation threshold.

The window should be like Figure 6 .

SLUU237 – January 2006 bq24720/21 EVM (HPA104) for Multi-Cell Synchronous 9

Switch-Mode Charger With System Power Selector and SMBus SBS-Like Interface

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Test Summary

Figure 6. The Software Main Window

Install J6.

Observe→ D7 (CHG EN) ON.

Change the B0 bit (CHGEND) of Control Register to 0. (Enable the charging). Click Write.

Measure→ V(J8(VBAT)) = 12.6 V ± 200 mV Observe→ D9 (ALARM) ON.

In the software main window, click Read All on the top part of the window.

Observe→ D9 (ALARM) off. Observe→ The B2 bit (NoVreg) of the Status Register turns green (voltage loop active). The window

should be like Figure 7 .

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Switch-Mode Charger With System Power Selector and SMBus SBS-Like Interface

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Test Summary

Figure 7. The Software Main Window

Observe → Make sure the phase node voltage (PH) and the inductor current waveforms look like

Figure 8 .

SLUU237 – January 2006 bq24720/21 EVM (HPA104) for Multi-Cell Synchronous 11

Switch-Mode Charger With System Power Selector and SMBus SBS-Like Interface

+ 23 hidden pages

Texas Instruments bq24720 EVM, bq24721 EVM User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1 Introduction

1.1 EVM Features

1.2 General Description

1.3 I/O Description

1.4 Controls and Key Parameters Setting

1.5 Recommended Operating Conditions

2 Test Summary

2.1 Definitions

2.2 Equipment

2.3 Equipment Setup

2.4 Procedure