DF04M View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
DF04M Datasheet PDF : 42 Pages
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AN1262 APPLICATION NOTE
Table 18. G1(jω) Implementation: secondary feedback (II)
Symbol
Definition
RL
RL ≈ 0.27 to 2.7 [kΩ]
RH
RH = V-----o---u-2-t--.-–-5----2---.--5-- ⋅ RL
RC, KB
RB
Select from table 17
RB < CTRmin ⋅ V-----o-I--Cu---tm--–---a--3-x--.--5-- ⋅ KB
CF
CF = -C----T----R-----m-R---a--B-x----⋅⋅---R(--R--H---C--⋅--O-G---M--1--P--0--/-/----R----C----)-
RF
RF = -2----⋅---π-----⋅--1-f--Z----⋅---C-----F- – RH
CCOMP
CCOMP = -2----⋅---π-----⋅---f--P-----⋅---(--R--1---C---O----M-----P---/--/---R-----C----)
More flexibility is given by the network illustrated in figure 14, applicable with the L6590 and L6590D which have
the error amplifier on board.
For this circuit, to be able to find a positive value for RF, the condition is:
C-C----T-T---R-R----m-m---a-i-n-x-
≤
G1c
⋅
tan
1----8π---0--
⋅
Φ
1c
-----------------R-----F---2------------------
⋅
1
+
R-R----CE--
⋅
V-----o-I--Cu---tm---–--a--3-x--.--5--
,
which is less stringent than (20). The resulting function is:
G1(jω) = -∆---V∆----VC----Oo---u-M--t--P-- = -∆---V--∆--C--V--O--E--M----P-- ⋅ -∆∆---V-I--C-E-- ⋅ -∆∆---II--CF-- ⋅ ∆--∆--V-I--F-K-- ⋅ ∆---∆-V--V--o--K-u---t = -(--R----E---C--+--T---R--R---C-m--)---a--·x----R⋅---R--B---E-⋅---R-⋅---R-H---F--⋅-2--C----F----1- ⋅ j--1ω--- ⋅ -1----+-----1j--ω---+---⋅--j-(-ω-R----⋅-H--R--+---F--R-2----F⋅---1C---)--F--⋅-2--C----F---1-- ,
and Table 19 shows how its quantities are defined.
Figure 14. Secondary feedback: TL431 + optocoupler circuit (III)
Vout
IF
RB
Vcc
RH
L6590
L6590D
VFB RC
COMP
IC
RF2
CF2
VE VK
RE
TL431
CF1 RF1
RL
27/42
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