nx2113 Microsemi Corporation, nx2113 Datasheet - Page 12
nx2113
Manufacturer Part Number
nx2113
Description
300khz & 600khz Synchronous Pwm Controller With Programmable Bus Uvlo
Manufacturer
Microsemi Corporation
Datasheet
1.NX2113.pdf
(19 pages)
order. Use the same power stage requirement as demo
board. The crossover frequency has to be selected as
F
and ESR zero F
Rev. 2.0
11/18/05
LC
Figure 10 - Bode plot of Type III compensator
<F
1.Calculate the location of LC double pole F
2.Set R
3. Set zero F
4. Calculate R
Design example for type III compensator are in
O
F
F
<F
ESR
LC
loop gain
power stage
compensator
ESR,
7kHz
2
2
60kHz
2
F
2
2
and F
equal to10k
Z1
ESR
F
Z2
Z2
.
4
F
O
0.78uH 660uF
L
ESR C
and C
4m
<=1/10~1/5F
LC
= F
1
OUT
1
1
1
LC
40dB/decade
3
C
and F
F
with the crossover frequency
OUT
660uF
O
OUT
then R
20dB/decade
F
F
P1
p1
ESR
s.
=F
1
F
= 10k
ESR
P2
.
LC
smaller than 1/10~ 1/5 of the switching frequency. Set
F
double pole by equation (11).
half the swithing frequency.
O
=45kHz.
Choose C
5. Calculate C
Choose C
6. Calculate C
Choose C
7. Calculate R
R
Choose R
C
C =
C
R =
3
2
3
1
4
=
=2nF
=
=11k
1.2k
2
2
12V
2
V
2
2
2V
2
2.75nF
48pF
V
2
2
OSC
in
1
2
1
3
3
1
=47pF.
=2.2nF, R
=2.7nF.
=1.2k
2
R
10k
60kHz 2.2nF
2
1
F
R
0.75 7kHz 11k
1
11k
P1
2
1
F
1
3
4
Z1
2
1
by equation (14) with pole F
by equation (13).
C
(
with zero F
C
1
F
45kHz 0.78uH
3
F
F
1
3
z2
R
O
P2
(
2.2nF
1
4
7kHz 60kHz
4
-
=11k
300kHz
NX2113/2113A
L
F
1
1
p1
C
)
-
out
z1
1
at 75% of the LC
660uF
)
p2
at
12