EVALHVLED805 Datasheet, PDF (2/9 Pages) STMicroelectronics – 4.2 W off-line LED driver with primary side regulation

Electrical schematic
1
Electrical schematic
EVALHVLED805
Figure 1.

EVALHVLED805 electrical schematic
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Efficiency measurement
Figure 2. Efficiency measurement with one, two or three LEDs





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The efficiency is always higher than 70 % when two or three LEDs are connected, whereas
it drops with one LED. The reason is that at low output voltage, the auxiliary voltage is not
able to supply the IC and the internal HV current generator self supplies the Vcc pin, thus
dissipating a power proportional to VIN.
The output current has been measured with two or three LEDs which obtain an accuracy
always below 5 %.
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Doc ID 18457 Rev 1