ncp15889 ON Semiconductor, ncp15889 Datasheet - Page 10

• Manufacturer Part Number: ncp15889
• Description: Single Phase Buck Controller
• Manufacturer: ON Semiconductor

Step 1: Set a value for R1 between 2 kW and 5 kW
Step 2: Pick compensation DC gain (R2/R1) for desired
close loop bandwidth.
Step 3: Place 1st zero at half the output filter double pole
frequency.
Step 4: Place 1st pole at ESR zero frequency.
b.. Output Filter Double Pole Frequency
c.. ESR Zero Frequency:
F
F
F
F
R1 :+ 4.12 kW
V
R2 :+ R1 @
R2 + 17.085 kW
C2 :+
C2 + 7.024
C1 :+
C1 + 1.542
lc
lc
ESR
ESR
RAMP
:+
+ 2.653 kHz
:+
+ 7.368 kHz
2 @ p @ L
2 @ L
C2 @ R2 @ 2 @ p @ F
:+ 1.1 V
2 @ p @ C
OUT
V
R2
10
10
RAMP
V
OUT
IN
1
@ C
-3
-3
OUT
1
C2
mF
mF
OUT
@ C
@ C
@
OUT
ESR
F
ESR
cross_over
F
* 1
lc
NCP1588, NCP1589
http://onsemi.com
10
Step 5: Place 2
frequency.
Step 6: Place 2
Step 7: R4 is sized to maintain the feedback voltage to
V
The Component values for Type III Compensation are:
R1 = 4.12 kW
R2 = 17.085 kW
R3 = 74.169 W
R4 = 3.878 kW
C1 = 0.0015 mF
C2 = 0.007 mF
C3 = 0.014 mF
NOTE: Recommend to change values to industry
ref
= 0.8 V.
R3 :+
R3 + 74.169 W
C3 :+
C3 + 0.014 mF
R4 :+
R4 + 3.878 kW
standard component values.
2@F
V
F
p @ R3 @ F
SW
OUT
V
nd
lc
R1
REF
nd
* 1
pole at half the switching frequency.
* V
1
zero at the output filter double pole
@ R1
REF
SW