IR3081 International Rectifier Corp., IR3081 Datasheet - Page 32

• Manufacturer Part Number: IR3081
• Description: Xphasetm Vr 10 Control Ic
• Manufacturer: International Rectifier Corp.

The over temperature setting voltage of Phases 3 and 4 is higher than the phase delay setting voltage,
VBIAS*RA
R
Bootstrap Capacitor C
Choose C
Decoupling Capacitors for Phase IC and Power Stage
Choose C
VOLTAGE LOOP COMPENSATION
Type III compensation is used for the converter with only ceramic output capacitors. The crossover frequency and
phase margin of the voltage loop can be estimated as follows.
Choose
Choose the desired crossover frequency fc (=140kHz) around fc1 estimated above, and calculate
Choose C
CURRENT SHARE LOOP COMPENSATION
The crossover frequency of the current share loop f
loop f
θ
C
C
C
R
R
R
f
C
PHASE41
CP
PHASE
C
CP
PHASE
FB
DRP
1
1
=
Page 32 of 39
=
=
=
=
C
90
=
10
2
4
2 (
33
32
. Choose the crossover frequency of current share loop f
π
π
(
−
π
R
R
∗
=
=
∗
∗
=10kΩ, R
FB
BST
VCC
A
CP1
FB
∗
PHASEx.
RA
C
R
(
f
V
tan(
C
L
1
f
1
CP
+
C
E
E
HOTSET
=0.1uF
=
=47pF to reduce high frequency noise.
PHASE
∗
=0.1uF, C
R
)
R
∗
∗
2
R
DRP
. 0
2
3
FB
C
V
∗
G
FB
R
) 5
∗
BIAS
1
E
L
CS
)
1
3
Pre-select R
DRP
R
E
∗
PHASE42
∗
∗
=
−
FB
=
∗
V
180
C
∗
V
−
π
O
10
RA
C
4
V
FB
BIAS
R
=
V
π
E
BIAS
VCCL
BST
HOTSET
FB
∗
PHASE
=
2
3
∗
∗
=
140
*
63
∗
R
∗
(
(
=768Ω, R
−
R
162
100
162
FB
=0.1uF
R
°
PHASE
V
3
*
1
∗
LE
HOTSET
∗
10
PHASEX1
*
V
=
+
V
10
RAMP
110
110
3
BIAS
=
31
. 1
∗
−
576
2
110
9
65
)
=
Ω
π
/
)
PHASE43
∗
=
) 6
∗
. 0
∗
∗
5
=10kΩ,
10
R
=
6 .
198
2 (
∗
(
62
PHASE
5
(
3
*
π
22
2 .
6
10
∗
∗
∗
8 .
nF
140
6
*
=2.80kΩ
−
22
9
10
31
8 .
−
. 1
, choose C
=
∗
*
−
*
=
79
10
6
10
10
2
*
. 1 (
7 .
*
3
62
−
CI
nF
)
79
10
6
2
)
)
∗
should be at least one decade lower than that of the voltage
3
∗
−
=
576
(
100
=
. 0
34
27
FB
. 2
198
6
∗
nF
8 .
67
*
=5.6nF
1
162
10
3 .
−
∗
k
CI
. 1
Ω
. 6
−
−
9
∗
=3.5kHz
79
) 8
20
/
0 (
) 6
∗
*
5 .
10
10
∗
*
(
*
22
−
10
10
3
,
*
and calculate C
−
3
10
3
=
/
−
) 6
887
6
∗
=
62
Ω
146
)
∗
162
kHz
*
SCOMP
. 0
75
=
. 1
,
10/01
65
IR3081
k
Ω
/04