Datasheet

DocID18279 Rev 5 13/37
ST1CC40 Application notes
37
Equation 2
Equation 3
where:
Equation 4
S
n
represents the slope of the sensed inductor current, S
e
the slope of the external ramp
(V
PP
peak-to-peak amplitude) that implements the slope compensation to avoid sub-
harmonic oscillations at duty cycle over 50%.
The sampling effect contribution F
H
(s) is:
Equation 5
where:
Equation 6
and
Equation 7
6.3 Error amplifier compensation network
The ST1CC40 device embeds the error amplifier (see Figure 6) and a pre-defined
compensation network which is effective in stabilizing the system in most of the application
conditions.

Z
1
ESR C
OUT

-------------------------------=

P
1
R
LOAD
C
OUT

------------------------------------- -
m
C
1D–0,5–
LC
OUT
f
SW

---------------------------------------------+=
m
C
1
S
e
S
n
------ +=
S
e
V
pp
f
SW
=
S
n
V
IN
V
OUT
–
L
----------------------------- - R
i
=








F
H
s
1
1
s

n
Q
P

-------------------
s
2

n
2
------++
------------------------------------------ -=

n
 f
SW
=
Q
P
1
 m
C
1D–0,5–
----------------------------------------------------------=