Electrical schematic

EVALHVLED805

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Doc ID 18457 Rev 1

1

Electrical schematic

Figure 1.

EVALHVLED805 electrical schematic

1.1

Efficiency measurement

Figure 2.

Efficiency measurement with one, two or three LEDs

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 %.