Texas Instruments bqSWITCHER bq241 Series User manual

Using the bq241xx (bqSWITCHER™)
User's Guide
Literature Number: SLUU200AJuly 2004 – Revised December 2007

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Contents
1 Introduction ................................................................................................................ 51.1 Background ....................................................................................................... 51.2 Performance Specification Summary .......................................................................... 52 Test Summary ............................................................................................................ 62.1 Equipment ......................................................................................................... 62.2 Setup............................................................................................................... 62.3 Test Procedure ................................................................................................... 73 Schematic .................................................................................................................. 94 Physical Layouts ....................................................................................................... 104.1 Board Layout .................................................................................................... 105 List of Materials ........................................................................................................ 136 References ............................................................................................................... 18
Important Notices ............................................................................................................... 19
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List of Figures
1 bq241xxEVM Schematic .................................................................................................... 92 bq241xxEVM Top Assembly .............................................................................................. 103 bq241xxEVM Top Silk Screen ............................................................................................ 114 bq241xxEVM Top Layer ................................................................................................... 115 bq241xxEVM Bottom Layer ............................................................................................... 12
List of Tables
1 Performance Specification Summary ..................................................................................... 62 I/O and Jumper Connections (Factory Jumper Selections shown in Bold Text) .................................... 73 bq24100EVM-001 List of Materials ..................................................................................... 134 bq24105EVM-002 List of Materials ..................................................................................... 145 bq24113EVM-003 List of Materials ..................................................................................... 156 bq24115EVM-004 List of Materials ..................................................................................... 167 bq24103EVM-005 List of Materials ..................................................................................... 178 bq24103AEVM-006 List of Materials .................................................................................... 18
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1 Introduction
1.1 Background
1.2 Performance Specification Summary
User's GuideSLUU200A – July 2004 – Revised December 2007
Using the bq241xx (bqSWITCHER™)
This user's guide describes the bq241xxEVM ( bqSWITCHER™) Evaluation Module. The EvaluationModule provides a convenient method for evaluating the performance of a charge management solutionfor portable applications using the bq241xx product family. A complete designed and tested charger ispresented. The charger is designed to deliver up to 2.0 A of continuous output current. The charger isprogrammed from the factor to deliver 1.33 A of charging current. Follow the instructions in this user'sguide that pertain to the specific bq241xxEVM (one-, two- or three-cell) to be evaluated. See thebqSWITCHER data sheet (SLUS606 ) prior to evaluation for detailed information on the bqSWITCHERdevice.
The bqSWITCHER series are highly integrated Li-Ion and Li-Pol switch-mode charge managementdevices targeted at a wide range of portable applications. The bqSWITCHER series offer integratedsynchronous PWM Controller and PowerFETs, high-accuracy current and voltage regulation, chargeconditioning, charge status, and charge termination, in a small thermally enhanced QFN package. Thesystem-controlled version provides additional input for full charge management under system control.
The bqSWITCHER charges the battery in three phases: conditioning, constant current, and constantvoltage. Charge is terminated based on user-selectable minimum current level. A programmable chargetimer provides a backup safety for charge termination. The bqSWITCHER automatically restarts thecharge if the battery voltage falls below an internal threshold. The bqSWITCHER automatically enterssleep mode when V
CC
supply is removed.
This section summarizes the performance specifications of the EVM. Table 1 gives the EVM performancespecifications. The TS pin has been disabled, for easier charging evaluation, by fixing its voltage to a setvalue. See the EVM schematic (Figure 1 ) and data sheet (SLUS606 ) for information on how to changeR10 and R11 values to use with an external thermistor
bqSWITCHER is a trademark of Texas Instruments.
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2 Test Summary
2.1 Equipment
2.2 Setup
Test Summary
Table 1. Performance Specification Summary
SPECIFICATION TEST CONDITIONS MIN TYP MAX UNIT
Input DC voltage, V
I(DC)
V
REG
+0.6 5.0 16 VBattery charge current, I
O(CHG)
1.33 2.0 APower dissipation bq24100 5 V ≤V
IN
≤16 V, V
(BAT)
= 4.2 V, I
OUT
= 1.33 A 0.6 W(1 cell)
bq24103 5 V ≤V
IN
≤16 V, V
(BAT)
= 4.2 V, I
OUT
= 1.33 A 0.6 Wbq24103A
bq24113
(1 cell)
bq24103 9 V ≤V
IN
≤16 V, V
(BAT)
= 8.4 V, I
OUT
= 1.33 A 0.85 Wbq24103A
bq24113
(2 cell)
bq24105 5 V ≤V
IN
≤16 V, V
(BAT)
= 4.2 V, I
OUT
= 1.33 A 0.0 Wbq24115
(1 cell
bq24105 9 V ≤V
IN
≤16 V, V
(BAT)
= 8.4 V, I
OUT
= 1.33 A 0.65 Wbq24115
(2 cell)
bq24105 13.5 V ≤V
IN
≤16 V, V
(BAT)
= 12.6 V, I
OUT
= 1.33 A 1.17 Wbq24115
(3 cell)
This chapter covers the test setups and tests performed, in evaluating the EVM.
•Power Source: Current limited 15 V lab supply with its current limit set to 25% above the programmedcharging current (1.7 A for setup from factory). This is basically a safety limit. The actual DC inputcurrent should be less than the charging current.•Two Fluke 75: (optional) To measure input and output voltage and drop across current sense resistor.
The bq241xx EVM board requires a regulated supply approximately 0.3 V minimum above the regulatedvoltage of the battery pack (1-cell pack: 4.2 V; 2-cell pack: 8.4 V; 3-cell pack: 12.6 V) to a maximum inputvoltage of 16 V
DC
.
A one- to three-cell battery pack is needed for EVM evaluation. The EVM should be chosen and set up tocharge the same numbers of cells as the evaluated (see Table 2 ).
Set up the EVM as shown in Table 2 . Preset the input supply to the desired voltage, turn off supply, andfinally connect supply to J1. Set the supply's current limit 25% above the programmed charging current.The test setup connections and jumper setting selections are configured for a stand-alone evaluation andcan be changed to interface with external hardware such as a microcontroller. See the EVM schematic(Figure 1 ) and data sheet (SLUS606 ) for functional information on other optional connections.
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2.3 Test Procedure
Test Summary
Table 2. I/O and Jumper Connections (Factory Jumper Selections shown in Bold Text)ASSEMBLY –001 –002 –003 –004 –005 -006
U1 Device bq24100 bq24105
(1)
bq24113
(2)
bq24115
(1)
bq24103
(2)
bq24103A
(2)
J1 DC+/DC-:Input 5 to 16 V
REG
+0.8 to 16
(1)
5 to 16 V
REG
+0.8 to 16
(1)
5 to 16
(2)
5 to 16
(2)
voltage range(V)
J2 BAT+/BAT-No. 1 1 1 1 1 1cell in series
Output 4.2 4.2
(1)
4.2
(2)
4.2
(1)
4.2
(2)
4.2
(2)
regulation
voltage (V)
J5 PG LED or EXT LED or EXT LED or EXT LED or EXT LED or EXT LED or EXT
J6 STAT1 LED or EXT LED or EXT LED or EXT LED or EXT LED or EXT LED or EXT
J7 STAT2 LED or EXT LED or EXT N/C no jumper N/C no jumper LED or EXT LED or EXT
J8 TTC or CMOD TTC no jumper TTC no jumper CMOD jumper HI CMOD jumper HI TTC no jumper TTC no jumper
J9 CE CE jumper LO CE jumper LO CE jumper LO CE jumper LO CE jumper LO CE jumper LO
J10 Cells or FB No jumper No jumper Cells jumper LO No jumper Cells jumper Cells jumper LOLO
(1)
R5 and R7 can be changed to regulate output between approximately 3.2 V to 15.5 V. Adjust the input voltage as required.Output set to operate at 4.2 VDC from the factory.(2)
To operate as a two cell version (8.4V), replace battery with a two-series cell pack, set J10 to High and adjust the Input voltagebetween 9.2 V to 16 V.
Set up the evaluation board as described above, by making the necessary I/O connections and jumperselections.
WARNINGPrior to test and evaluation, it is important to verify that the EVMselected is set up correctly for the battery pack to be charged;several evaluation modules have a CELLs option that can beprogrammed for two different size – number of series cells. TIhighly recommends that the battery pack to be charged, hasinternal protection as a safety backup.
1. Apply power to the board with the power supply, preset to the suggested value in Table 2 , and useapproximately 1.7 A for the current limit setting.2. The PG LED and STAT1 should light, if the battery is charging.3. The bq241xx enters pre-conditioning mode if the battery is below the V
(LOWV)
threshold. In this mode,the bq241xx pre-charges the battery with a low current programmed by the ISET2 pin. If the R
SET1
andR
SET2
resistors are the same value then the precharge is one tenth the fast charge current (I
PRE-CHG
=1.33 A/10 = 133 mA) until the battery voltage reaches the V
(LOWV)
threshold or until the precharge timerexpires. If the timer expires then the charge current is terminated and the bq241xx enters fault mode.STAT1 and STAT2 (if available) LEDs go dark when in fault mode.
Note: There are several non-charging modes that share this status state. Toggling input power orbattery replacement resets fault mode.
4. Once the battery voltage is above the V
(LOWV)
threshold, the battery enters fast charge mode. ThisEVM is programmed for approximately 1.3 A of fast charging current. The PG and STAT1 LEDs shouldbe on.5. Once the battery reaches voltage regulation (4.2 V) the current tapers down as the battery reaches itsfull capacity. The PG and STAT1 LEDs should light.
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Test Summary
6. When the current reaches the taper termination threshold, set by the R
SET2
resistor, the charge isterminated. The PG LED should be still lit and the STAT1 LED should turn off and STAT2 LED lights.7. If the battery discharges down to the recharge threshold, the charger starts fast charging. The PG LEDshould remain lit, the STAT2 LED should turn off and STAT1 LED lights.
An alternative method of testing the EVM is with a source meter, that can sink or source current. This caneasily be adjusted to test each mode, in place of a battery.
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3 Schematic
Schematic
Figure 1 shows the schematic diagram for the EVM.
Figure 1. bq241xxEVM Schematic
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4 Physical Layouts
4.1 Board Layout
Physical Layouts
This chapter contains the board layout and assembly drawings for the EVM.
Figure 2 shows the top assembly of the EVM. Figure 3 shows the top silk screen. Figure 4 shows the toplayer. Figure 5 shows the bottom layer view.
Figure 2. bq241xxEVM Top Assembly
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