Datasheet

IN
EN
SW
D
FB
FREQ
AGND
COMP
SL22
SS
1
4
6
8
3
7
2
5
PGND
9
10
SW
TPS61087
V
5V±20%
IN
Cin
2*10µF/
16V
Cby
1µF/16V
L
6.8µH
Css
100nF
Rcomp
51kΩ
Ccomp
1.5nF
Rsense
15 Ω
Cout
4*10µF/
25V
V
500mA
S
3S3P wLED
LWE67C
Dz
BZX84C18V
Rlimit
R1
180kΩ
AnalogBrightnessControl
PWMSignal
3.3V~wLEDoff
0V~l =30mA (eachstring)
Canbeusedswingingfrom0Vto3.3V
LED
R2
127kΩ
110 Ω
optional
TPS61087
www.ti.com SLVS821C –MAY 2008–REVISED JULY 2013
Figure 23. Simple Application (5 V input voltage) (f
S
= 650 kHz) for wLED Supply (3S3P) with Adjustable
Brightness Control using an Analog Signal on the Feedback Pin (with optional clamping Zener diode)
REVISION HISTORY
Changes from Original (May 2008) to Revision A Page
• Added text to the Detailed Description - following the Block Diagram ................................................................................. 8
Changes from Revision A (June 2008) to Revision B Page
• Added DSC package to ORDERING INFORMATION ......................................................................................................... 2
• Deleted Lead temperature from Absolute Maximum Ratings ............................................................................................... 2
• Deleted R
θJA
from DISSIPATION RATINGS ......................................................................................................................... 2
• Changed f
osc
to f
S
in Electrical Characteristics Boost Converter Oscillator Frequency ........................................................ 3
• Changed FREQ = high to FREQ = V
IN
in Electrical Characteristics Boost Converter Oscillator Frequency ....................... 3
• Changed FREQ = low to FREQ = GND in Electrical Characteristics Boost Converter Oscillator Frequency ...................... 3
• Added DSC package to PIN ASSIGNMENT ........................................................................................................................ 4
• Added Maximum load current vs. Input voltage graph ......................................................................................................... 4
• Added Maximum load current vs. Input voltage graph ......................................................................................................... 4
• Changed f to f
S
and Frequency to Oscillator Frequency in Figure 11 .................................................................................. 7
• Changed f to f
S
and Frequency to Oscillator Frequency in Figure 12 .................................................................................. 7
• Changed the text in the Detailed Description. ...................................................................................................................... 8
• Changed "inductor current ripple is below 20%" to " inductor current ripple is below 35%" .............................................. 10
• Added output capacitor calculation ..................................................................................................................................... 13
Changes from Revision B (March 2010) to Revision C Page
• Added V
IH
Test Condition for EN, V
IN
= 2.5 V to 4.3 V ......................................................................................................... 3
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