Datasheet

L6738A Application details
Doc ID 18134 Rev 2 23/32
Figure 10. Example of type III compensation.
● Open loop converter singularities:
a)
b)
● Compensation Network singularities frequencies:
a)
b)
c)
d)
To place the poles and zeros of the compensation network, the following suggestions may
be followed:
Gain
[dB]
Log (Freq)
0dB
open loop
EA gain
closed
loop gain
compensation
gain
open loop
converter gain
F
LC
F
ESR
F
Z1
F
Z2
F
P1
F
P2
20log (R
F
/R
FB
)
20log (V
IN
/∆V
OSC
)
F
0dB
F
LC
1
2π LC
OUT
⋅
-------------------------------------=
F
ESR
1
2π C
OUT
ESR⋅⋅
-------------------------------------------------=
F
Z1
1
2π R
F
C
F
⋅⋅
------------------------------------=
F
Z2
1
2π R
FB
R
S
+()C
S
⋅⋅
----------------------------------------------------------=
F
P1
1
2π R
F
C
F
C
P
⋅
C
F
C
P
+
----------------------
⎝⎠
⎛⎞
⋅⋅
--------------------------------------------------------=
F
P2
1
2π R
S
C
S
⋅⋅
------------------------------------=