L6563TR View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'L6563TR' PDF : 37 Pages View PDF
L6563 - L6563A
Application information
to set the output voltage at the desired values use the following design procedure:
1. Determine the input RMS voltage Vinclamp that produces Vo = Vox:
Equation 6
Vinclamp
=
-V----o----x----–-----V----o---1-
Vo2 – Vo1
⋅
Vi
n2
–
-V----o----x----–-----V----o---2-
Vo2 – Vo1
⋅
Vin1
and choose a value Vinx such that Vin2 = Vinx < Vinclamp. This will result in a limitation of the
output voltage range below Vox (it will equal Vox if one chooses Vinx = Vinclamp)
2. Determine the divider ratio of the MULT pin (pin 3) bias:
Equation 7
k = ------------3--------------
2 ⋅ Vinx
and check that at minimum mains voltage Vin1 the peak voltage on pin 3 is greater than
0.65V.
3. Determine R1, the upper resistor of the output divider:
Equation 8
R1
=
∆----V-----o-
20
⋅
106
4. Calculate the lower resistor R2 of the output divider and the adjustment resistor RT:
Equation 9
R2 = 2.5 ⋅
R1 ⋅
-------------------------------------V-----i--n---2----–-----V----i--n---1--------------------------------------
(Vo1 – 2.5) ⋅ Vin2 – (Vo2 – 2.5) ⋅ Vin1
RT =
2⋅
k⋅
R1 ⋅
V-----i--n---2----–-----V----i--n---1-
Vo2 – Vo1
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