IR3623MPBF_1 IRF [International Rectifier], IR3623MPBF_1 Datasheet - Page 21

• Manufacturer Part Number: IR3623MPBF_1
• Description: HIGH FREQUENCY 2-PHASE, SINGLE OR DUAL OUTPUT SYNCHRONOUS STEP DOWN CONTROLLER WITH OUTPUT TRACKING AND SEQUENCING
• Manufacturer: IRF [International Rectifier]

Based on the frequency of the zero generated by
output capacitor and its ESR versus crossover
frequency, the compensation type can be
different.
compensation types and location of crossover
frequency.
Table1- The compensation type and location
The details of these compensation types are
discussed in application note AN-1043 which can
be downloaded from IR Web-Site.
For this design we have:
V
V
V
V
g
L
C
F
These result to:
F
F
F
Select crossover frequency:
F
Since: F
selected to place the pole and zeros.
www.irf.com
F
Compensator
type
m
o
s
LC
ESR
s/2
o
in
o
osc
ref
o
o
=0.34uH, DCR=1.1mOhm
=600kHz
TypeIII(PID)
TypeIII(PID)
=1.8V
=100kHz
=15x22uF, ESR= 0.33mOhm
=2800umoh
=13.2V
Method A
Method B
=0.8V
<
=15kHz
=300kHz
TypII(PI)
=1.25V
=1.46MHz
F
ESR
and
LC
<F
The
of F
F
o
o
<F
≤
ESR
F
F
F
(
1/5
s/2
LC
LC
LC
table
<F
versus F
F
<F
<F
<F
~
ESR
ESR
1/10
ESR
o
o
<F
<F
vs. F
, typeIII method B is
<F
s/2
ESR
below
)
*
<F
o
o
F
<F
<F
s
o
ESR
s/2
s/2
shows
Output
capacitor
Electrolytic
, Tantalum
Tantalum,
Ceramic
ceramic
the
The following design rules will give a crossover
frequency
switching frequency. The higher the band width,
the potentially faster the load transient response.
The DC gain will be large enough to provide high
DC-regulation accuracy (typically -5dB to -12dB).
The phase margin should be greater than 45
overall stability.
Desired Phase Margin:
Calculate
C
C
C
Calculate
F
F
F
F
Select
R
Select
R
R
R
Z
Z
P
P
11
12
10
7
8
6
5
2
2
2
2
≥
=
=
=
=
=
=
=
=
=
=
V
g
2
2
F
26
2
F
373
2
2
2
o
m
π
π
o
o
π
π
π
:
:
V
−
*
.
*
C
;
*
*
F
*
ref
79
*
*
V
.
R
10
C
C
Z1
21
1
F
F
F
C
1
R
1
ref
1
1
1
1
1
7
10
10
kHz
Z1
P
o
=
=
11
R
8
3
−
+
+
−
kHz
≥
*
,
*
*
*
*
,
0
0
*
7
approximately
R
Sin
Sin
Sin
Sin
L
0
C
R
F
F
R
.
.
R
*
o
68
5
.
6
12
P
Z
6
72
V
7
7
*
2
2
;
and
Θ
Θ
Θ
Θ
*
in
and
;
R
;
C
;
nF
−
C
F
C
K
R
5
o
R
Z
12
11
Ω
*
8
2
=
R
8
V
C
=
;
=
=
;
6
5
R
osc
and
10
1.19nF,
.
53
0
:
45
Select
6
.
:
;
63
=
C
pF
K
IR3623MPbF
10
8
Θ
K
Ω
F
.
,
05
=
Ω
max
P3
,
:
Select
0
,
K
one-sixth
=
Select
R
Select
.
=
67
Select
Ω
0.5
7
π
3
,
=
nF
10K
*
Select
:
,
F
C
:
:
s
R
:
12
Ω
C
R
5
11
=
8
=
:
47
=
=
6
of
R
1.2nF
0
.
49
6
pF
.
68
=
o
K
the
8
for
K
Ω
21
.
Ω
06
K
Ω