Texas Instruments bq24650EVM User manual

User's Guide
SLUU444A–August 2010–Revised October 2010
bq24650EVM Synchronous, Switch-Mode, Battery Charge
Controller for Solar Power
This user's guide describes the features and operation of the bq24650EVM Evaluation Module (EVM). The
EVM assists users in evaluating the bq24650 synchronous battery charger. The EVM is also called the
HPA639 A. The manual includes the bq24650EVM bill of materials, board layout, and schematic.
Contents
1 Introduction .................................................................................................................. 1
1.1 Features ............................................................................................................. 1
1.2 General Description ................................................................................................ 2
1.3 I/O Description ...................................................................................................... 2
1.4 Control and Key Parameters Settings ........................................................................... 3
1.5 Recommended Operating Conditions ........................................................................... 3
2 Test Summary ............................................................................................................... 5
2.1 Definitions ........................................................................................................... 5
2.2 Safety ................................................................................................................ 5
2.3 Quality ............................................................................................................... 5
2.4 Apparel .............................................................................................................. 5
2.5 Equipment ........................................................................................................... 5
2.6 Equipment Setup ................................................................................................... 6
2.7 Procedure ........................................................................................................... 7
3 PCB Layout Guideline ...................................................................................................... 9
4 Bill of Materials, Board Layout, and Schematic ....................................................................... 10
4.1 Board Layout ...................................................................................................... 11
List of Figures
1 Original Test Setup for HPA639 A Evaluation Board .................................................................. 6
2 Top Layer................................................................................................................... 11
3 Second Layer .............................................................................................................. 12
4 Third Layer ................................................................................................................. 13
5 Bottom Layer............................................................................................................... 14
6 Top Assembly.............................................................................................................. 15
7 Bottom Assembly.......................................................................................................... 16
8 bq24650EVM Schematic ................................................................................................. 17
List of Tables
1 I/O Description............................................................................................................... 2
2 Control and Key Parameters Settings.................................................................................... 3
3 Recommended Operating Conditions.................................................................................... 3
1 Introduction
1.1 Features
• Synchronous switch-mode battery charge controller for solar power
1
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Introduction www.ti.com
• Resistor-programmable up to 26-V battery voltage
• Input operating range: 5 V–28 V
• LED indication for charge status
• Test points for key signals available for testing purposes; easy probe hook-up.
• Jumpers available; easy-to-change setting
1.2 General Description
The bq24650 is a highly integrated switch-mode battery charge controller. It provides input voltage
regulation, which reduces charge current when input voltage falls below a programmed level. When the
input is powered by a solar panel, the input regulation loop maintains the panel at maximum power output.
The bq24650 offers a constant-frequency, synchronous PWM controller with high-accuracy current and
voltage regulation, charge preconditioning, charge termination, and charge status monitoring.
The bq24650 changes the battery in three phases: preconditioning, constant current, and constant
voltage. Charge is terminated when the current reaches one-tenth of the fast charge rate. A
programmable fast-charge timer provides a safety backup. The precharge timer is fixed at 30 minutes.
The bq24650 automatically restarts the charge cycle if the battery voltage falls below an internal threshold
and enters a low, quiescent-current sleep mode when the input voltage falls below the battery voltage.
The bq24650 supports the battery from 2.1 V to 26 V with VFB set to a 2.1-V feedback reference. The
charge current is programmed by selecting an appropriate sense resistor. The bq24650 is available in a
16-pin, 3.5x3.5 mm2, thin QFN package.
For details, see the bq24650 data sheet (SLUSA75).
1.3 I/O Description
Table 1. I/O Description
Jack Description
J1–VIN Positive input
J1–PGND Negative input
J2–VSYS Connected to system
J2–VOUT Connected to charger output
J2–PGND Ground
J2–TS Temperature qualification voltage Input
2bq24650EVM Synchronous, Switch-Mode, Battery Charge Controller for SLUU444A–August 2010–Revised October 2010
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MPPSET
R17
V = 1.2 V 1 +
R19
æ ö
´ç ÷
è ø
OUT
R13
V = 2.1 V 1 +
R15
æ ö
´ç ÷
è ø
www.ti.com Introduction
1.4 Control and Key Parameters Settings
Table 2. Control and Key Parameters Settings
Jack Description Factory Setting
JP1 Select external TS input or internal valid TS setting Jumper ON 1-2 (external TS)
1-2 : External TS input
2-3 : Internal valid TS setting
JP2 The pullup power source supplies the LEDs when JP2 ON. LED has no Jumper ON (LED power available)
power source when JP2 is OFF.
JP3 TERM_EN setting Jumper ON 2-3 (enable termination)
2-3 : Connect TERM_EN to VREF to enable termination
1-2 : Connect TERM_EN to GND to disable termination
JP4 Charger enable/disable setting. MPPSET is pulled to GND and the charger Jumper OFF (disable charger)
is disabled when JP4 OFF; charger is enabled when JP4 is ON.
1.5 Recommended Operating Conditions
Table 3. Recommended Operating Conditions
Symbol Description Min Typ Max Unit Notes
Supply voltage, VIN Input voltage 5 20 28 V
Battery voltage, VOUT Voltage applied at VOUT terminal 2.1 12.6 26 V
of J2
Supply current Maximum input current 0 8 A
Charge current, Ichrg Battery charge current 0 2 8 A For charge current above 2 A, replace R6
and L1 with high-current rating
components
Operating junction temperature range, TJ0 125 °C
The bq24650EVM board requires a regulated supply approximately 1 V minimum above the regulated
voltage of the battery pack to a maximum input voltage of 28 Vdc. The charge voltage is programmed via
a resistor divider from the battery to ground, with the midpoint tied to the VFB pin.
R13 and R15 can be changed to regulate output between approximately 2.1 V to 26 V.
(1)
It is set at 12.6 Vdc from the factory.
A solar panel has a unique point on the V-I or V-P curve, called the maximum power point (MPP), at
which the entire photovoltaic (PV) system operates with maximum efficiency and produces its maximum
output power. The constant voltage algorithm is the simplest maximum power point tracking (MPPT)
method. The bq24650 automatically reduces charge current, so the maximum power point is maintained
for maximum efficiency.
If the solar panel or other input source cannot provide the total power of the system and bq24650 charger,
the input voltage drops. Once the voltage sensed on the MPPSET pin drops below 1.2 V, the charger
maintains the input voltage by reducing the charge current.
(2)
It is set at 17.8 Vdc from the factory.
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CHARGE
6
40 mV
I =
R
Introduction www.ti.com
Battery current is sensed by resistor RSR connected between SRP and SRN. The full-scale differential
voltage between SRP and SRN is fixed at 40 mV.
(3)
It is set at 2 Adc from the factory.
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www.ti.com Test Summary
2 Test Summary
2.1 Definitions
This procedure details how to configure the HPA639 A evaluation board. The following naming
conventions are followed on the test procedure.
VXXX : External voltage supply name (VADP, VBT, VSBT)
LOADW: External load name (LOADR, LOADI)
V(TPyyy): Voltage at internal test point TPyyy. For example, V(TP1) means the voltage at TP1.
V(Jxx): Voltage at jack terminal Jxx.
V(TP(XXX)): Voltage at test point XXX. For example, V(MPPSET) means the voltage at the test point
which is marked as MPPSET.
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 : Internal jumper Jxx terminals are shorted
Jxx OFF: Internal jumper Jxx terminals are open
Jxx (-YY-) ON: 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 occur. If they do not occur, the unit under test has failed.
Assembly drawings have location for jumpers, test points and individual components.
2.2 Safety
1. Safety Glasses are to be worn.
2. This test must be performed by qualified personnel who are trained in electronics theory and
understand the risks and hazards of the assembly to be tested.
3. ESD precautions must be followed while handling electronic assemblies and performing this test.
4. Precautions must be observed to avoid touching areas of the assembly that may get hot or present a
shock hazard during testing.
2.3 Quality
1. Test data can be made available on request from Texas Instruments.
2.4 Apparel
1. Electrostatic smock
2. Electrostatic gloves or finger cots
3. Safety glasses
4. Ground ESD wrist strap.
2.5 Equipment
2.5.1 Power Supplies
Power Supply #1 (PS#1): a power supply capable of supplying 30 V at 3 A is required.
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BQ24650 EVM
HPA639
VIN
J1
PGND
VSYS
J2
PGND
VOUT
APPLICATION CIRCUIT
TP2
SW
U1
V
Iin
I
Power supply
#1
Iout
V
Isys
V
ILoad #1
Load #2
I
LEDPWR
TS
/STAT1 /STAT2
JP3 TEST POINTS
D4 D5
JP2JP4
CE
TERM_EN
SATATUS
SETTINGS
JP1
TS
External
Internal
EN
DIS
Test Summary www.ti.com
2.5.2 Loads
LOAD#1 A 30-V (or greater), 5-A (or greater) electronic load that can operate at constant current and
constant voltage mode.
LOAD#2: An HP 6060B 3-V to 60-V/0A to 60-A, 300-W system dc electronic load or equivalent.
2.5.3 Meters
Seven Fluke 75 multimeters (equivalent or better) or four equivalent voltage meters and three equivalent
current meters.
The current meters must be capable of measuring 5-A+ current.
2.6 Equipment Setup
1. Set the power supply #1 (PS#1) for 21-V ±500-mVdc, 2.5-A ±0.1-A current limit, and then turn off
supply.
2. Connect the output of PS#1 in series with a current meter (multimeter) to J1 (VIN, PGND).
3. Connect a voltage meter across J1 (VIN, PGND).
4. Connect Load#1 in series with a current meter to J2 (VOUT, PGND). Turn off Load#1.
5. Connect Load#2 in series with a current meter to J2 (VSYS, PGND). Turn off Load#2.
6. Connect a voltage meter across J2 (VOUT, PGND).
7. Connect a voltage meter across J2 (VSYS, PGND).
8. Check all jumper shunts. JP1: connect 1-2 (External TS); JP2: ON; JP3: connect 2-3 (Enable
TERM_EN); JP4: OFF.
Figure 1. Original Test Setup for HPA639 A Evaluation Board
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2.7 Procedure
2.7.1 Power Supply and VREF
Ensure that Section 2.6 steps are followed.
Disconnect LOAD#1#2. Turn on PS#1.
Measure →V(J2(VSYS)) = 21 V ±500 mV
Measure →V(J2(VOUT)) = 0 V ±500 mV
Measure →V(TP(VREF)) = 3.3 V ±200 mV
Measure →V(TP(REGN)) = 0 V ±200 mV
2.7.2 Charger Enable and Battery Detection
Connect 2-3 of JP1 (Internal TS); Short JP4 (Charger Enable)
Measure →V(TP(VREF)) = 3.3 V ±200 mV
Measure →V(TP(REGN)) = 6 V ±200 mV
Observe →V(J2(VOUT))=12.6 V ±500 mV
Observe →D4 (/STAT1) OFF, D5 (/STAT2) OFF
2.7.3 Charge Current/Voltage Regulation and Battery Temperature Qualification
Reconnect LOAD#2, and turn on. Use the constant voltage mode. Set the output voltage to 8 V.
Measure →I(J2(VOUT)) = 0.2 A ±100 mA
Observe →D4 (/STAT1) ON, D5 (/STAT2) OFF
Increase the voltage of LOAD#2 to be 10.5 V.
Measure →I(J2(VOUT)) = 2 A ±200 mA
Observe →D4 (/STAT1) ON, D5 (/STAT2) OFF
Open 2-3 of JP1
Measure →I(J2(VOUT)) = 0 A ±100 mA
Observe →D4 (/STAT1) OFF, D5 (/STAT2) OFF
Connect 2-3 of JP1 (Internal TS)
Measure →I(J2(VOUT)) = 2 A ±200 mA
Observe →D4 (/STAT1) ON, D5 (/STAT2) OFF
2.7.4 Charger Termination
Increase the voltage of LOAD#2 slowly to approximately 12.6 V.
Observe →I(J2(VOUT)) decreases from 2 A while V(J2(VOUT)) becomes constant.
Observe →I(J2(VOUT)) drops to zero when it is less than 0.2 A.
2.7.5 Maximum Power Point, Input Voltage Regulation
Connect the output of the Load#1 in series with a current meter (multimeter) to J2 (SYS, PGND). Ensure
that a voltage meter is connected across J2 (SYS, PGND). Resume other status as in Section 2.7.3.
(Short JP1, JP4, set LOAD#2 to 10.5 V.)
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2.7.6 Final Step
Turn on the power of Load#1. Set the load current to 1 A. Increase the load current slowly and observe
the following.
Observe →V(J1(VIN)) = 17.8 V ±500 mV.
Keep increasing I(J2(VSYS)),
Observe →I(J2(VOUT)) decreases from 2 A toward 0 A while V(J1(VIN)) become constant 17.8 V ±500
mV. Ensure that I(J2(VOUT))= 0 A ±100 mA and →(J2(VSYS)) = 2.4 A ±200 mA.
2.7.7 Test Complete
Turn off the power supply, and remove all connections from the unit under test.
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3 PCB Layout Guideline
1. It is critical that the exposed thermal pad on the backside of the bq24650 package be soldered to the
PCB ground. Ensure that sufficient thermal vias are right underneath the IC, connecting to the ground
plane on the other layers.
2. The control stage and the power stage must be routed separately. At each layer, the signal ground and
the power ground are connected only at the thermal pad.
3. Charge current sense resistor must be connected to SRP, SRN with a Kelvin contact. The area of this
loop must be minimized. The decoupling capacitors for these pins must be placed as close to the IC as
possible.
4. Decoupling capacitors for VREF, VCC, REGN must make the interconnections to the IC as short as
possible.
5. Decoupling capacitors for BAT must be placed close to the corresponding IC pins, and make the
interconnections to the IC as short as possible.
6. Decoupling capacitor(s) for the charger input must be placed close to the Q1A drain and Q1B source.
7. Take the EVM layout for design reference.
9
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Bill of Materials, Board Layout, and Schematic www.ti.com
4 Bill of Materials, Board Layout, and Schematic
Bill of Materials
Bill of Materials
001 RefDes Value Description SIZE PART NUMBER MFR
3 C1, C2, C7 10 µF Capacitor, Ceramic, 35V, X7R, 10% 1210 STD STD
3 C3, C5, C8 1.0 µF Capacitor, Ceramic, 35V, X7R, 10% 805 STD STD
1 C4 2.2 µF Capacitor, Ceramic, 35V, X7R, 20% 1210 STD STD
3 C6, C11, C12 0.1 µF Capacitor, Ceramic, 50V, X7R, 10% 603 STD STD
0 C9, C13 Open Capacitor, Ceramic, 50V, X7R, 10% 603 STD STD
2 C10, C16 1.0 µF Capacitor, Ceramic, 16V, X7R, 10% 805 STD STD
1 C14 0.1 µF Capacitor, Ceramic, 16V, X7R, 10% 603 STD STD
2 C15, C17 22 pF Capacitor, Ceramic, 50V, X7R, 10% 603 STD STD
2 D1, D3 PDS1040-13 Diode, 10A 40V Schottky Barrier Rectifier PowerDI 5 PDS1040-13 Diodes
1 D2 ZLLS350-7 Diode, Schottky, 1.16A, 40-V SOD-523 ZLLS350-7 Zetex
2 D4, D5 LTST-C190GKT Diode, LED, Green, 2.1V, 20mA, 6mcd 603 LTST-C190GKT Lite On
1 J1 ED120/2DS Terminal Block, 2 pin, 15A, 5.1mm 0.40 x 0.35 inch ED120/2DS OST
1 J2 ED120/4DS Terminal Block, 4 pin, 15A, 5.1mm 0.80 x 0.35 inch ED120/4DS OST
2 JP2, JP4 PEC02SAAN Header, 2 pin, 100mil spacing 0.100 inch x 2 PEC02SAAN Sullins
2 JP1, JP3 PEC03SAAN Header, 3 pin, 100mil spacing 0.100 inch x 3 PEC03SAAN Sullins
1 L1 10 µH Inductor, SMT, 102mΩ, 7.0A, 20% 0.255 x 0.270 inch IHLP2525CZER100M01 Vishay
IHLP2525CZEB100M01
1 Q1 Si7288-T1 FET, Dual N Chan, 40V, 20A, 19 mΩSO8-PowerPak SI7288DP-T1 Vishay/
Siliconix
1 Q2 2N7002-7-F MOSFET, N-ch, 60V, 115mA, 1.2ΩSOT23 2N7002-7-F Diodes
2 R1, R2 3.9 Resistor, Chip, 1/4W, 5% 1206 STD STD
1 R3 10 Resistor, Chip, 1/8W, 5% 805 STD STD
0 R4, R8 Open Resistor, Chip, 1/8W, 5% 805 STD STD
1 R5 2.2 Resistor, Chip, 1/10W, 5% 603 STD STD
1 R6 0.02 Resistor, Metal Film, 1/4 watt, 0.1%, Axial 1206 WSLP1206R0200FEA Vishay
2 R7, R10 0 Resistor, Chip, 1/10W, 5% 603 STD STD
1 R9 5.23K Resistor, Chip, 1/10W, 1% 603 STD STD
1 R11 100 Resistor, Chip, 1/10W, 5% 603 STD STD
1 R12 30.1k Resistor, Chip, 1/10W, 1% 603 STD STD
2 R13, R17 499k Resistor, Chip, 1/10W, 1% 603 STD STD
1 R14 10k Resistor, Chip, 1/10W, 5% 603 STD STD
2 R15, R18 100k Resistor, Chip, 1/10W, 1% 603 STD STD
0 R16 Open Resistor, Chip, 1/10W, 5% 603 STD STD
2 R20, R21 10k Resistor, Chip, 1/8W, 5% 805 STD STD
1 R19 36k Resistor, Chip, 1/8W, 5% 805 STD STD
0 TP1, Open Test Point, 0.020 Hole 0.020" STD STD
TP3–TP7
0 TP2 Open Adaptor, 3.5-mm probe clip (or 131-4244-00) 0.200 inch 131-5031-00 Tektronix
1 U1 BQ24650RVA IC, High Efficiency Synchronous Switch-Mode Fast QFN16[RVA] BQ24650RVA TI
Charge Controller for Solar Power
10 CE, GND, TP-5002 Test Point, White, Thru Hole Color Keyed 0.100 x 0.100 inch 5002 Keystone
MPPSET,
REGN,
STAT1,
STAT2, TS,
TERM_EN,
VCC, VREF
1 – PCB, 3 In x 3 In x 0.062 In HPA639 Any
4 Bumper foot (install after final wash) 0.440 x 0.2 SJ-5303 3M
4 Shunt, 100-mil, Black 0.100 929950-00 3M
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