HVLED805

[ramator]

Posted on January 06, 2012 at 10:09

Hello,

I want to execute my project with HVLED805 where input voltage is 176…264 V.

Output voltage for LED equal 18 V, output current 0.45 A.

Edesign proposed the transformer with widings: Primary – 145 turns, Aux – 29 turns, Secondary – 34 Turns, transformer core EE16, Reflected voltage 80 V.

I can’t allocate these winding therefore in program VIPer Design Software v.2.24 I have counted

analogous

transformer with widings: Primary – 120 turns, Aux – 17 turns, Secondary – 20 Turns, transformer core EE16, Reflected voltage 115 V.

Edesign recommended Rsense=0.931 ohm.

For calculation of this parameter with the new transformer I have used the equation (7) of datasheet (

Off–line LED driver with primary–sensing HVLED805 -

http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00287280.pdf

:(

Iout=(Npri/Nsec)(Vc_led/2Rsense)

In this equation

Iout

and  

Vc_led

remains invariable.

After substitution of new values

Npri/Nsec

I have received Rsense=1.31 ohm

From here I had a first question: whether correctly I have made calculations?

In advance I thank you for the answer

[ramator]

Posted on March 15, 2012 at 16:11

Unfortunately

, this forum

is not supported

by experts

of

STMicroelectronics

.

The all questions

I was able

to solve

without help.

The results

are visible

in the photo.

The device

provides

i

n the LED

current of

0.55 A

with voltage of

18volts.

The lamp

produces a

luminous flux of

1700

lumens

.

Case temperature

is 52degrees

Celsius.

Heat sink

of LEDs has temperature

55

degrees Celsius.

It's all right

.

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