AnsweredAssumed Answered

HVLED805

Question asked by kosenko.stanislaw on Jan 6, 2012
Latest reply on Mar 15, 2012 by kosenko.stanislaw
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

Outcomes