IR3080 International Rectifier, IR3080 Datasheet - Page 25

• Manufacturer Part Number: IR3080
• Description: XPHASE VRD10 CONTROL IC WITH VCCVID & OVERTEMP DETECT
• Manufacturer: International Rectifier

C
ceramic capacitor between 10pF and 220pF is usually enough.
Type III Compensation for AVP Applications
Determine the compensation at no load, the worst case condition. Assume the time constant of the resistor and
capacitor across the output inductors matches that of the inductor, the crossover frequency and phase margin of the
voltage loop can be estimated by Equations (32) and (33), where R
Choose the desired crossover frequency fc around fc1 estimated by Equation (32) 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
CP1
DRP
CP
Page 25 of 41
and C
is optional and may be needed in some applications to reduce the jitter caused by the high frequency noise. A
VO+
VDRP
from Equations (35) and (36).
CP
have limited effect on the crossover frequency, and are used only to fine tune the crossover frequency
RFB
RDRP
(a) Type II compensation
θ
C
C
C
R
R
f
C
C
CP
CP
FB
FB
DRP
1
1
1
=
=
=
=
=
=
2
90
=
2 (
4
10
π
1
2
π
(
VDAC
π
−
*
R
R
∗
∗
FB
FB
C
∗
V
A
FB
FB
RCP
f
O
R
E
f
tan(
C
L
1
C
*
CP
+
∗
E
∗
)
R
G
Figure 17. Voltage loop compensation network
2
R
R
R
+
∗
. 0
-
CCP1
1
DRP
∗
CS
FB
DRP
FB
C
+
) 5
L
to
1
E
1
*
2 (
E
EAOUT
)
∗
R
∗
∗
π
180
FB
π
C
C
CP
CCP
*
E
FB
∗
f
∗
C
R
R
and C
R
FB
*
LE
FB
C
1
*
=
∗
EAOUT
R
V
CP
2
3
C
PWMRMP
R
)
from Equations (37) and (38).
2
FB
FB1
VO+
VDRP
RFB1
according to Equation (34), and determine C
(b) Type III compensation
LE
RFB
RDRP
CFB
CDRP
is the equivalent resistance of inductor DCR.
VDAC
FB
RCP
+
-
CCP1
EAOUT
CCP
(30)
(31)
(32)
(33)
(34)
(35)
(36)
EAOUT
9
/30/04
IR3080
FB
and