STMicroelectronics LED7707 Application Note page 15

AN2810
channels are in parallel, a single string of 700 mA-rated LEDs is required as load
(Figure 10).
Figure 10. Efficiency measurement setup
Figure 11
signal at two different input voltages.
Figure 11. Efficiency vs. DIM duty cycle,
ROW1 ROW1
and 12 shows two efficiency measurements versus the duty cycle of the dimming
V =12 V, 6 rows, 10 white
IN
LEDs in series, I
OUT
Doc ID 14893 Rev 1
DIM DIM
GND GND
VIN- VIN-
VIN+ VIN+
VBOOST VBOOST
V-Meter V-Meter
10 WLEDs 700mA array 10 WLEDs 700mA array
Figure 12. Efficiency vs. DIM duty cycle,
= 360 mA
Getting started
PWM Generator PWM Generator
4.5V – 32V @ 2A 4.5V – 32V @ 2A
Power Supply Power Supply
+ +
A-Meter A-Meter
V-Meter V-Meter
A-Meter A-Meter
V =24 V, 6 rows, 10 white
IN
LEDs in series, I
OUT
= 360 mA
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