Datasheet

22uF
5V / 2A
10uF
2.2 µH
(5 .. 17)V
3.3nF
TPS62143
PVIN
AVIN
EN
SS/TR
DEF
FSW
SW
VOS
PG
FB
AGND
PGND
100k
TRSSFB
RAV
/
.. ××= m52640
22uF
10uF
2.2 µH(4 .. 17) V
0.15R187k
ADIM
PVIN
AVIN
EN
SS/TR
DEF
FSW
SW
VOS
PG
FB
AGND
PGND
TPS62140
TPS62140, TPS62140A
TPS62141, TPS62142, TPS62143
SLVSAJ0B –NOVEMBER 2011–REVISED JUNE 2013 www.ti.com
Application Example As Power LED Supply
The TPS62140 can be used as a power supply for power LEDs. The FB pin can be easily set down to lower
values than nominal by using the SS/TR pin. With that, the voltage drop on the sense resistor is low to avoid
excessive power loss. Because this pin provides 2.5 µA, the feedback pin voltage can be adjusted by an external
resistor per Equation 15. This drop, proportional to the LED current, is used to regulate the output voltage (anode
voltage) to a proper level to drive the LED. Both analog and PWM dimming are supported with the TPS62140.
Figure 42 shows an application circuit, tested with analog dimming:
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Figure 42. Single Power LED Supply
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The resistor at SS/TR sets the FB voltage to a level of about 300 mV and is calculated from Equation 15.
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(15)
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The device now supplies a constant current, set by the resistor at the FB pin, by regulating the output voltage
accordingly. The minimum input voltage must be rated according to the forward voltage needed by the LED
used. More information is available in the application note SLVA451.
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Typical Applications
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Figure 43. 5-V/2-A Power Supply
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