Datasheet

f − Frequency − kHz
Gain − dB
Phase – °
–180
–120
f
P
–60
0
60
120
180
Phase
Gain
+
´
p´ ¦
= ´ ´ ´
+
æ ö æ ö
+ ´ +
ç ÷ ç ÷
´ p ´ ¦ ´ p ´ ¦
è ø è ø
Z
EA EA EA
P1 P2
s
1
2
R2
H G R
R2 R1
s s
1 1
2 2
¦ =
p
´ ´
P1
EA
1
2 R C 4
¦ =
p
´ ´
P2
1
(optional)
2 R3 C5
¦
p
´ ´
Z
1
=
2 R3 C4
TPS61175
SLVS892B –DECEMBER 2008–REVISED FEBRUARY 2012 www.ti.com
Figure 16. Bode Plot of Power Stage Gain and Phase
The TPS61175 COMP pin is the output of the internal trans-conductance amplifier. Equation 17 shows the
equation for feedback resistor network and the error amplifier.
(17)
where G
EA
and R
EA
are the amplifier’s trans-conductance and output resistance located in the ELECTRICAL
CHARACTERISTICS table.
(18)
C5 is optional and can be modeled as 10 pF stray capacitance. (19)
and
(20)
Figure 17 shows a typical bode plot for transfer function H(s).
16 Submit Documentation Feedback Copyright © 2008–2012, Texas Instruments Incorporated
Product Folder Link(s): TPS61175