IR3081A International Rectifier Corp., IR3081A Datasheet - Page 24

• Manufacturer Part Number: IR3081A
• Description: Xphasetm Vr 10 Control Ic
• Manufacturer: International Rectifier Corp.

Choose the desired crossover frequency fc around fc1 estimated by Equation (27) or choose fc between 1/10 and
1/5 of the switching frequency per phase, and select the components to ensure the slope of close loop gain is -20dB
/Dec around the crossover frequency. Choose resistor R
R
R
and transient load response. Determine R
C
ceramic capacitor between 10pF and 220pF is usually enough.
Type III Compensation for Non-AVP Applications
Resistor R
the crossover frequency fc between 1/10 and 1/5 of the switching frequency per phase and select the desired phase
margin θc. Calculate K factor from Equation (34), and determine the component values based on Equations (35) to
(39),
DRP
CP
CP1
Page 24 of 39
and C
is optional and may be needed in some applications to reduce the jitter caused by the high frequency noise. A
from Equations (30) and (31).
FB
CP
is chosen according to Equations (13), and resistor R
have limited effect on the crossover frequency, and are used only to fine tune the crossover frequency
θ
C
C
C
C
C
C
R
R
K
R
R
C
CP
CP
CP
CP
FB
FB
DRP
CP
FB
FB
1
=
1
1
1
=
=
=
tan[
=
=
=
=
=
=
=
90
=
2 (
R
4
2
2
10
2
1
2
2
π
π
π
FB
(
π
π
π
π
−
4
R
R
∗
∗
∗
∗
∗
∗
∗
∗
∗
A
FB
FB
f
f
f
(
R
2 (
K
K
tan(
C
C
f
C
f
f
1
L
180
θ
C
C
C
+
CP
∗
E
π
∗
∗
C
)
∗
1
R
∗
R
2
1
R
R
R
∗
∗
. 0
K
DRP
∗
K
FB
+
CP
FB
FB
C
) 5
L
1
∗
to
∗
1
1
E
L
E
5 .
)
∗
R
C
E
∗
∗
)]
CP
180
∗
FB
π
C
C
V
CP
C
O
FB
E
V
E
O
R
∗
and C
∗
FB
∗
R
FB
f
K
1
C
=
)
∗
2
CP
V
2
3
∗
PWMRMP
V
R
PWMRMP
from Equations (32) and (33).
FB
FB1
according to Equation (29), and determine C
DRP
and capacitor C
DRP
are not needed. Choose
(28)
(29)
(30)
(31)
(32)
(33)
(34)
(35)
(36)
(37)
(38)
(39)
IR3081A
1/31
/05
FB
and