Datasheet

Zmod
ESR OUT
1
f
2 R Cp
=
´ ´
R
O
C
O
R
C
C
C
C
P
Type2A
COMP
VSENSE
V
OUT
gm
EA
V
ref
ref
DCEA DCEA
OUT
V
G = A ×
V
P0
O C
1
f
2 R Cp
=
´ ´
DCEA
0
EA
A
R
gm
=
Z1
C C
1
f
2 R Cp
=
´ ´
TPS5401
www.ti.com SLVSAB0 –DECEMBER 2010
(27)
A type 2A compensation scheme is recommended for the TPS5401. As R
C
, C
C
, C
P
shown in Figure 41, the
compensation components are chosen to set the desired loop crossover frequency and phase margin for output
filter components. The type 2A compensation has the following characteristics: a dc gain, a low-frequency pole,
and a mid-frequency zero / pole pair.
Figure 41. The Compensation Recommended for the TPS5401
The dc gain is determined by Equation 28:
(28)
where:
A
DCEA
is the error amplifier open-loop dc gain. It is 10,000 V/V.
The low-frequency pole is determined by Equation 29:
(29)
where:
R
O
is the output resistance of the error amplifier. It can be calculated by Equation 30.
(30)
The mid-frequency zero is determined by Equation 31.
(31)
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