User's Guide
SLUU279 – August 2007
bq24018 (bqTINY™)
1
2
3
4
Contents
Introductions ..................................................................................................................
Test Summary ................................................................................................................
Reference .....................................................................................................................
Schematic, Physical Layouts, and Bill of Materials......................................................................
1
2
4
4
List of Figures
1
2
3
4
EVM Schematic Diagram ...................................................................................................
Assembly View ...............................................................................................................
Top Layer .....................................................................................................................
Bottom Layer .................................................................................................................
5
6
6
7
List of Tables
1
2
1
Performance Specification Summary ..................................................................................... 2
Bill of Materials ............................................................................................................... 7
Introductions
This user's guide describes the bq24018 (bqTINY™) evaluation module. The EVM provides a convenient
method for evaluating the performance of a charge-management solution for portable applications using
the bq24018 product family. A complete designed and tested charger is presented. The charger is
designed to deliver up to 1 A of continuous charge current, but is programmed for 0.7 A, for single-cell
Li-Ion or Li-Pol applications using a dc power supply.
1.1
Background
The bqTINY series are highly integrated Li-Ion and Li-Pol linear charge-management devices targeted at
space-limited portable applications. In a small package, the bqTINY series offer integrated PowerFET and
current sensor, reverse blocking diode, high-accuracy current and voltage regulation, charge status, and
charge termination.
The bqTINY charges the battery in three phases: conditioning, constant current, and constant voltage.
Charge terminates on the basis of minimum current. An internal charge-timer provides backup safety for
charge termination. The bqTINY automatically restarts the charge if the battery voltage falls below an
internal threshold and automatically enters sleep mode when VCC supply is removed.
1.2
Performance Specification Summary
This section summarizes the performance specifications of the EVM. Table 1 gives the performance
specifications of the EVM.
bqTINY is a trademark of Texas Instruments.
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Test Summary
Table 1. Performance Specification Summary
Specification
VI(DC)
Input dc voltage
IO(CHG)
Battery charge current
See
Power dissipation
(V(DC+) – V(BAT+)) × I(CHG)
(1)
2
Test Conditions
Min
VREG +0.5
(1)
Typ
Max
5.0
5.4
(1)
Unit
0.7
1
A
1.5
W
V
This input voltage maximum is a function of the maximum allowable power dissipation on the IC. The current level is
programmed for 0.7 A. If the programmed charge is changed, then the maximum input voltage must be adjusted. PmaxIC = 1.5
Watt = ICHG(VDC+ – VBAT+).
Test Summary
This chapter describes the test setups used and the tests performed in evaluating the EVM.
Setup: The bq24018 EVM board requires a single-cell Li-Ion or Li-Pol battery pack and a 5-VDC, 1-A
power source to provide input power. The test setup connections and jumper setting selections are
configured for a stand-alone evaluation but can be changed to interface with external hardware, such as a
microcontroller.
2.1
2.2
I/O and Jumper Connections
Jack
Connect To:
J1-DC+
Power supply positive, preset to 5.0VDC, 1-A current limit
J1-DC–
Power supply ground
J2-BAT+
Positive battery pack terminal
J2-BAT–
Negative battery pack terminal
J2–TTE
NC required — pulled down with 10 kΩ resistor on the EVM
J2-BAT–
NC
J3-STAT1
External hardware if J4-EXT is jumpered (not jumpered from factory)
J3-STAT2
External hardware if J5-EXT is jumpered (not jumpered from factory)
J3-DC-
Return for J3 signals
J3–CE
NC required — pulled down with 10-kΩ resistor on the EVM
J4 (Jumper)
STAT1 indication location — LED (EVM) | EXT
J5 (Jumper)
STAT2 indication location — LED (EVM) | EXT
Test Procedure
Set up the evaluation board as described above, by making the necessary I/O connections and jumper
selections. Before test and evaluation, it is important to verify that the maximum power dissipation
on the IC is not exceeded: P(MAX) = 1.5 watts.
1. Turn on the power supply, which was preset to 5.0 VDC and 1 A for the current-limit setting.
2. The bq24018 enters preconditioning mode if the battery is below the V(LOWV) threshold. In this mode,
the bq24018 precharges the battery with a low current (typically IO(CHG)/10 = 0.7A/10 = 70 mA) until the
battery voltage reaches the V(LOWV) threshold or until the precharge timer expires. If the timer expires,
then the charge current is terminated, the bq24018 enters fault mode, and both LEDs turn off. Toggling
input power or battery replacement resets fault mode.
3. Once the battery voltage is above the V(LOWV) threshold, the battery enters fast-charge mode. This
EVM is programmed for 0.7 A of fast-charging current.
4. Once the battery reaches voltage regulation (4.36 V), the current tapers down as the battery reaches
its full capacity.
5. The battery remains at the fast-charge mode until the fast-charge timer expires, the charge taper time
expires, or the charge termination threshold is reached.
6. If the battery discharges to the recharge threshold, the charger starts fast charging.
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Test Summary
In place of a battery, a source meter that can sink current can easily be adjusted to test each mode.
Another way to briefly see each mode on a scope is to connect a 1-mF capacitor and a 10-kΩ resistor on
the output in place of a battery to observe the power-up and cycling between voltage regulation and fast
charge via the refresh threshold.
Note:
Because of the battery-detection circuit, it is not possible to switch-in static load resistors
to jump between regulation and constant-current modes. An alternate procedure
described below uses a dynamic load to replace the battery circuit. That procedure allows
testing of each mode.
This is an alternative way of testing the EVM using a dynamic load board in place of a battery. The circuit
is adjusted to work with the displayed parts and their inherent thresholds. The sequence of the test
procedure is important because of the active battery-detection circuit, refresh feature, and precharge and
fast-charge current levels (switching load in or out has different results in different modes). No damage
should occur, but results might be different than anticipated if the procedure is altered.
2.2.1
1.
2.
3.
4.
Equipment
Power source: current-limited 5-V lab supply with its current limit set to 1.0 A ±0.1 Amp
Two Fluke 75, equivalent or better
Oscilloscope – TDS220 or better
Load test board:
Power Supply
5.1± 0.1 V
Current Limit 1± 0.1 A
S1
DC+
S3
S2
1N4148
D1
BAT+
R3
3 kW, 0.25 W
DC-
R4
66.5 W, 0.25 W
R5
66.5 W, 0.25 W
S4
R1
5 W, 5 W
+
BAT-
Q1
Si4410DY
R6
10 kW, 0.25 W
C1
2000 mF, 25 V
Q2
Si4410DY
R7
10 kW, 0.25 W
Load Board
for HPA261
2.2.2
Equipment Setup
1. Connect the load board to the BAT+ and BAT–. Set SW1 through SW4 in the closed position.
2. Connect a voltage meter to the BAT+/BAT– output to monitor the output voltage (range 0 to 5 V).
3. Set the lab supply for 5.1 V ±0.1VDC, 1.0 ±0.1 A current limit, and then turn off the supply. Connect
the source supply to a current meter and to J1, noting polarity. (may use an internal source current
meter if it has 5% or better accuracy.)
4. Install shunt jumpers on the LED pins 1 and 2 of each header J4 and J5.
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Reference
2.2.3
Procedure
1. Ensure that EQUIPMENT SETUP steps are followed. (switches should be in the closed position,
shunts installed, and power source set to 5.1 V/±0.1 VDC.) Turn on the power source.
2. Verify the red LED is lit.
3. Verify output voltage charges to 2.7 ± 0.2V.
4. Open switch, SW2, and then close switch, SW2
5. Verify output voltage settles at 3.5 ± 0.2V.
6. Verify that the input current is 0.73±0.08 Amps
7. Open switch, SW3
8. Verify that the input current is 0.13±0.03 Amps
9. Verify the output voltage, 4.360V±0.050 VDC
10. Open switch SW2.
11. Verify, with a scope (1V/div, 200ms/div), that the output charges to 4.4V ± 0.1V and discharges to
3.6V±0.5V at a frequency of 1Hz±0.5 Hz.
12. Verify that the LEDs flash between RED (D1) and GREEN (D2, mostly on green).
13. Close switch, SW2 and SW3 (all switches should be closed now) and power down supply.
14. EVM is good if all tests have passed. Remove I/O connections.
15. If there are more EVMs to test, loop back to 7.1 and continue until all units have been tested.
3
Reference
1. bq2401x data sheet (SLUS530)
4
Schematic, Physical Layouts, and Bill of Materials
This chapter contains the schematic diagram, the board layouts and assembly drawings, and the bill of
materials required for the EVM.
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Schematic, Physical Layouts, and Bill of Materials
Schematic
U1
bq24018
4.1
Figure 1. EVM Schematic Diagram
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Schematic, Physical Layouts, and Bill of Materials
4.2
4.2.1
Physical Layouts
Board Layout
Figure 2 shows the assembly view of the EVM. Figure 3 shows the top layer. Figure 4 shows the bottom
layer.
Figure 2. Assembly View
Figure 3. Top Layer
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Schematic, Physical Layouts, and Bill of Materials
Figure 4. Bottom Layer
4.3
Bill of Materials
Table 2 lists materials required for the EVM.
Table 2. Bill of Materials
Item
Number
bq24018
Ref Des
1
0
2
1
3
Description
Size
MFR
Part Number
C1
Capacitor, ceramic, X5R, 1 μF, 10 V
805
Panasonic
ECJ-2YB1A105K
C2
Capacitor, ceramic, X5R, 1 μF, 10 V
805
Panasonic
ECJ-2YB1A105K
1
C3
Capacitor, ceramic, X7R, 0.47 μF, 16 V
805
Panasonic
ECJ-2YB1C474K
4
1
D1
Diode, LED, red, 1.8 V, 20 mA, 20 mcd
603
Lite-On
160-1181-1-ND
5
1
D2
Diode, LED, green, 2.1 V, 20 mA, 6 mcd
603
Lite-On
160-1183-1-ND
6
1
J1
Terminal block, 2 pin, 6 A, 3,5 mm
0.27 × 0.25
OST
ED1514
7
2
J2, J3
Terminal block, 4 pin, 6 A, 3,5 mm
0.55 × 0.25
OST
ED1516
8
2
J4, J5
Header, 3 pin, 100 mil spacing, (36-pin strip)
Sullins
PTC36SAAN
9
2
R1, R2
Resistor, chip, 1.5 kΩ, 1/16 W, 1%
603
Std
Std
10
0
R3
Resistor, chip, 1 MΩ, 1/16 W, 1%
602
Std
Std
11
2
R5, R6
Resistor, chip, 10 kΩ, 1/16 W, 1%1
603
Std
Std
12
1
R4
Resistor, chip, 1.3 kΩ, 1/16 W, 1%
603
Std
Std
13
1
U1
IC, single Li-Ion/Li-Polymer, charge manager
MLP10
TI
bq24018DRC
14
2
—
Shunt, 100-mil, black
0.100
3M
929950-00
15
1
—
PCB, bq24018, 1.6 in × 1.3 in × 0.031 in
Any
HPA261
0.100 × 3
Notes: 1) These assemblies are ESD sensitive; ESD precautions must be observed.
2) These assemblies must be clean and free from flux and all contaminants. Use of no-clean flux is not acceptable.
3) These assemblies must comply with workmanship standards IPC-A-610 Class 2.
4)
Reference designators marked with an asterisk (**) cannot be replaced by substitutes. All other components can be replaced with equivalent
manufacturer components.
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EVALUATION BOARD/KIT IMPORTANT NOTICE
Texas Instruments (TI) provides the enclosed product(s) under the following conditions:
This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION PURPOSES
ONLY and is not considered by TI to be a finished end-product fit for general consumer use. Persons handling the product(s) must have
electronics training and observe good engineering practice standards. As such, the goods being provided are not intended to be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including product safety and environmental
measures typically found in end products that incorporate such semiconductor components or circuit boards. This evaluation board/kit does
not fall within the scope of the European Union directives regarding electromagnetic compatibility, restricted substances (RoHS), recycling
(WEEE), FCC, CE or UL, and therefore may not meet the technical requirements of these directives or other related directives.
Should this evaluation board/kit not meet the specifications indicated in the User’s Guide, the board/kit may be returned within 30 days from
the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY SELLER TO BUYER
AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF
MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user indemnifies TI from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge.
EXCEPT TO THE EXTENT OF THE INDEMNITY SET FORTH ABOVE, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY
INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
TI currently deals with a variety of customers for products, and therefore our arrangement with the user is not exclusive.
TI assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or
services described herein.
Please read the User’s Guide and, specifically, the Warnings and Restrictions notice in the User’s Guide prior to handling the product. This
notice contains important safety information about temperatures and voltages. For additional information on TI’s environmental and/or
safety programs, please contact the TI application engineer or visit www.ti.com/esh.
No license is granted under any patent right or other intellectual property right of TI covering or relating to any machine, process, or
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FCC Warning
This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION PURPOSES
ONLY and is not considered by TI to be a finished end-product fit for general consumer use. It generates, uses, and can radiate radio
frequency energy and has not been tested for compliance with the limits of computing devices pursuant to part 15 of FCC rules, which are
designed to provide reasonable protection against radio frequency interference. Operation of this equipment in other environments may
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Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2007, Texas Instruments Incorporated
EVM WARNINGS AND RESTRICTIONS
It is important to operate this EVM within the input voltage range of 0 V to 5.4 V and the output voltage range of 0 V to 4.25 V.
Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the EVM. If there are questions
concerning the input range, please contact a TI field representative prior to connecting the input power.
Applying loads outside of the specified output range may result in unintended operation and/or possible permanent damage to the EVM.
Please consult the EVM User's Guide prior to connecting any load to the EVM output. If there is uncertainty as to the load specification,
please contact a TI field representative.
During normal operation, some circuit components may have case temperatures greater than 60°C. The EVM is designed to operate
properly with certain components above 60°C as long as the input and output ranges are maintained. These components include but are
not limited to linear regulators, switching transistors, pass transistors, and current sense resistors. These types of devices can be identified
using the EVM schematic located in the EVM User's Guide. When placing measurement probes near these devices during operation,
please be aware that these devices may be very warm to the touch.
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2007, Texas Instruments Incorporated
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