nx2114 Microsemi Corporation, nx2114 Datasheet - Page 11

• Manufacturer Part Number: nx2114
• Description: 300khz & 600khz Synchronous Pwm Controller
• Manufacturer: Microsemi Corporation

order. The crossover frequency has to be selected as
F
and ESR zero F
frequency at 1/10~ 1/5 of the switching frequency. Set
Rev. 4.0
06/20/06
LC
Figure 10 - Bode plot of Type III compensator
<F
Design example for type III compensator are in
1. Calculate the location of LC double pole F
2. Set R
3. Set zero F
4. Calculate R
O
F
F
<F
ESR
LC
loop gain
power stage
compensator
ESR,
6.2kHz
2
2
48kHz
2
2
F
and F
2
Z1
equal to10.2k
ESR
F
Z2
Z2
.
ESR C
F
7.5m
O
4
1.5uH 440uF
<=1/10~1/5F
L
LC
= F
and C
1
1
OUT
1
1
LC
40dB/decade
and F
F
3
C
OUT
with the crossover
O
440uF
OUT
20dB/decade
F
F
P1
then R
p1
ESR
s.
=F
F
ESR
P2
1
= 10.2k
.
LC
F
double pole by equation (11).
half the switching frequency.
O
=30kHz.
Choose C
5. Calculate C
C
Choose C
6. Calculate C
Choose C
7. Calculate R
R
Choose R
C =
C
R =
3
2
3
1
4
=
=2.2nF
=
=19.2k
2
1.5k
2
2
2
1.7V 2
1.55nF
V
2
2
2
48pF
2
5V
V
OSC
in
1
1
2
1
3
3
=47pF.
10k
=2.2nF, R
=1.5nF.
=1.5k .
R
0.75 6.2kHz 22.1k
48kHz 2.2nF
1
F
1
F
2
1
R
2
22.1k
P1
Z1
4
2
1
3
1
(
by equation (14) with pole F
by equation (13).
with zero F
F
C
R
F
C
1
1
z2
P2
(
F
3
30kHz 1.5uH
4
3
6.2kHz 48kHz
O
2.2nF
1
-
4
=22.1k .
F
NX2114/2114A
1
150kHz
p1
1
L
)
C
z1
-
out
at 75% of the LC
1
440uF
)
p2
at
11