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DCTRL
VO AC
IL
1 A/div
t-Time-500 s/divm
V =11V,
I =20mAx6=120mA,
PWMFreq=500Hz,
Duty=50%
IN
O
100mVac/div
5V/div
Input/Output Connector Descriptions
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Figure 5. Output Ripple at PWM Dimming with C
O
= 4.7 μF
Note that when measuring the WLED output voltage for the efficiency computation, the output voltage
from the IC's I
OUT
pin to ground was used, which includes the voltage drop across the series ammeter,
used to measure the WLED current, as well as the voltage drop across the internal current sink circuit and
external current setting resistor.
6
TPS61181EVM-259 / TPS61182EVM-259 SLVU223B February 2008Revised May 2011
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