LSP5523

Document number: DS44073 Rev. 7 - 2

9 of 17

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May 2022

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LSP5523

Stability Compensation

COMP

R

COMP

C

COMP 1

C

COMP2

CCOMP2 is needed only for high ESR output capacitor

Figure 2. Stability Compensation

The feedback loop of the IC is stabilized by the components at the COMP pin, as shown in Figure 2. The DC

loop gain of the system is determined by the following equation:

COMP

VEA

OUT

VDC

G

A

I

V

A

925

.

0



The dominant pole P1 is due to CCOMP1:

1

1

2

COMP

VEA

EA

P

C

A

G

f





The second pole P2 is the output pole:

OUT

OUT

OUT

P

C

V

I

f



2

2 

The first zero Z1 is due to RCOMP and CCOMP1:

1

1

2

1

COMP

COMP

Z

C

R

f





And finally, the third pole is due to RCOMP and CCOMP2 (if CCOMP2 is used):

2

C O M P

C O M P

3

P

C

R

π

2

1

f



The following steps should be used to compensate the IC:

STEP1. Set the crossover frequency at 1/10 of the switching frequency via RCOMP:

V

G

G

f

C

V

R

COMP

EA

SW

OUT

OUT

COMP

925

.

0

10

2







But limit RCOMP to 10KΩ maximum. More than 10 KΩ is easy to cause overshoot at power on.

(4)

(5)

(6)

(7)

(8)

(9)