Datasheet

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ESR RHPZ
OUT
PS
SENSE
P
s s
1 1
2 2
R (1 D)
G (s) He(s)
s
2 R
1
2
P
O
2
2
R C2
¦ =
p ´ ´
¦ »
p
´ ´
ESR
ESR
1
2 R C2
2
O
IN
RHPZ
OU T
R V
=
2 L V
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p ´
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2
2
S
W
SW
1
He(s)
Se
s 1 (1 D) 0.5
Sn
s
1
( )
=
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¦
p ´ ¦
-
´
O
UT D IN
SENSE
V + V V
Sn = R
L
( )
m
+
´
- ´
0.32 V / R4 0.5 A
Se =
16 1 D 6pF 6 pF
TPS61175
www.ti.com SLVS892B –DECEMBER 2008–REVISED FEBRUARY 2012
(10)
Where
(11)
(12)
(13)
And
(14)
He(s) models the inductor current sampling effect as well as the slope compensation effect on the small signal
response. Note that if Sn > Se, e.g., when L is smaller than recommended, the converter operates as a voltage
mode converter and the above model no longer holds.
The slope compensation in TPS61175 is shown as follow
(15)
Where R4 is the frequency setting resistor (16)
Figure 16 shows a bode plot of a typical CCM boost converter power stage
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