NCP1588

http://onsemi.com

9

b.. Output Filter Double Pole Frequency

F

F

1

2

@ p @ L

c.. ESR Zero Frequency:

F

F

1

2

@ p @ C

Step 1: Set a value for R1 between 2 k

W and 5 kW

R1 :

+ 4.12 kW

Step 2: Pick compensation DC gain (R2/R1) for desired

close loop bandwidth.

V

R2 :

+ R1 @

V

RAMP

V

IN

@

F

lc

R2

+ 17.085 kW

Step 3: Place 1st zero at half the output filter double pole

frequency.

C2 :

+

2

@ L

R2

C2

+ 7.024

mF

Step 4: Place 1st pole at ESR zero frequency.

C1 :

+

C2

C2

@ R2 @ 2 @ p @ F

C1

+ 1.542

mF

frequency.

R3 :

+

R1

F

SW

2

@F

lc

* 1

R3

+ 74.169 W

C3 :

+

1

p @ R3 @ F

SW

C3

+ 0.014 mF

Step 7: R4 is sized to maintain the feedback voltage to

R4 :

+

V

V

R4

+ 3.878 kW

The Component values for Type III Compensation are:

R1 = 4.12 k

W

R2 = 17.085 k

W

R3 = 74.169

W

R4 = 3.878 k

W

C1 = 0.0015

mF

C2 = 0.007

mF

C3 = 0.014

mF

NOTE:

Recommend to change values to industry

standard component values.