DocID025039 Rev 1

11/27

AN4339

Description

27

1.3.5

Multiplier setting

Equation 12

Select

Vmultpkmax = 2.65 V

Vmultpkmin = 0.88 V

Resistor divider ratio:

Equation 13

Kp = 7.17 E - 03

Let

RmultL= 47 K



Equation 14

So

RmultH = RmultL/Kp

RmultH = 6555 K



Select

Actual divider ratio:

Equation 15

Kp = 7.12 E - 03

Rsense calculation:

Equation 16

Vcxpk = 1.33

Vmultpkmin

(As per the L6564 datasheet, MULT setting).

Equation 17

Vcxpk = 1.17 V

Considering the saturation current of primary = 20% higher of maximum peak current at 90

VAC.

Equation 18

Ipkp_s = 1.7 A

Rcs = 0.68 E

Vmultpkmin

Vmultpkmiax

Vpkmin

Vpkmax

-----------------------



=

Kp

Vmultpkmax

Vpkmax

------------------------------------

=

R

---------------

=