Datasheet

L6563 - L6563A Application information
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5. Check that the maximum current sourced by the TBO pin (pin 6) does not exceed the
maximum specified (0.25mA):
Equation 10
In the following Mathcad® sheet, as an example, the calculation is shown for the circuit
illustrated in Figure 40. Figure 41 shows the internal block diagram of the tracking boost
function.
Design data
Vin
1
:= 88V Vo
1
:= 200V
Vin
2
:= 264V Vo
2
:= 385V
Vox ;= 400V
∆Vo ;= 40V
Step 1
choose: Vin
x
: = 270V
Step 2
Step 3
I
TBOmax
3
R
T
-------
0.25 10
3–
⋅≤=
Vin
clamp
:
Vox Vo
1
–
Vo
2
Vo
1
–
---------------------------
Vin
2
⋅=
Vox Vo
2
–
Vo
2
Vo
1
–
---------------------------
Vin
1
⋅–
Vin
clamp
= 278.27V
k:
3
2Vin
x
⋅
-----------------------=
k = 7.857 x 10
-3
R1:
Vo∆
20
-----------
10
6
⋅=
R1 = 2 x 10
6
Ω