Feedback Loop Compensation

1

f

0

2

L

C

OUT

=

p ´

´

(19)

Z

OUT

1

f

2

ESR

C

=

p ´

´

(20)

UDG-08109

+

COMP

C1

R2

C2

R

BIAS

C3

R3

R1

V

REF

V

OUT

FB

TPS51113, TPS51163

Since TPS51113/TPS51163 utilizes voltage-mode control for buck converters, Type III network is recommended

for loop compensation. Suitable poles and zeros can be set by choosing proper parameters for the loop

compensation network.

To calculate loop compensation parameters, the poles and zeros for the buck converter should be obtained. The

following equation.

Also, the ESR zero of the buck converter can be achieved.

Figure 8 shows the configuration of Type III compensation. The transfer function of the compensator is described

in Equation 21. Also, poles and zeros for the Type III network are shown in Equation 22 through Equation 26.

Figure 8. Type III Compensation Network

14

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