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BQ24100_08 Datasheet, PDF (23/38 Pages) Texas Instruments – SYNCHRONOUS SWITCHMODE, LI-ION AND LI-POLYMER CHARGE-MANAGEMENT IC WITH INTEGRATED POWER FETs (bqSWITCHER™) | |||
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bq24100, bq24103, bq24103A
bq24104, bq24105, bq24108, bq24109
bq24113, bq24113A, bq24115
www.ti.com .................................................................................................................................................. SLUS606N â JUNE 2004 â REVISED NOVEMBER 2008
bqSWITCHER SYSTEM DESIGN EXAMPLE
The following section provides a detailed system design example for the bq24100.
System Design Specifications:
⢠VIN = 16V
⢠VBAT = 4.2V (1-Cell)
⢠ICHARGE = 1.33 A
⢠IPRECHARGE = ITERM = 133 mA
⢠Safety Timer = 5 hours
⢠Inductor Ripple Current = 30% of Fast Charge Current
⢠Initiate Charge Temperature = 0°C to 45°C
1. Determine the inductor value (LOUT) for the specified charge current ripple:
DIL + ICHARGE ICHARGERipple
LOUT
+
VBAT ÇVINMAX
VINMAX Æ
* VBATÇ
DIL
LOUT + 16
4.2 (16 * 4.2)
(1.1 106) (1.33
0.3)
LOUT + 7.06 mH
(13)
Set the output inductor to standard 10 µH. Calculate the total ripple current with using the 10 µH inductor:
DIL
+
VBAT ÇVINMAX
VINMAX Æ
* VBATÇ
LOUT
DIL + 16
4.2 (16 * 4.2)
(1.1 106) (10 10*6)
DIL + 0.282 A
(14)
Calculate the maximum output current (peak current):
I
LPK
+
IOUT
)
DIL
2
ILPK
+
1.33
)
0.282
2
ILPK + 1.471 A
(15)
Use standard 10 µH inductor with a saturation current higher than 1.471A. (i.e., Sumida CDRH74-100)
Copyright © 2004â2008, Texas Instruments Incorporated
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Product Folder Link(s): bq24100 bq24103 bq24103A bq24104 bq24105 bq24108 bq24109 bq24113 bq24113A
bq24115
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