IR3523MTRPBF International Rectifier, IR3523MTRPBF Datasheet - Page 28

• Manufacturer Part Number: IR3523MTRPBF
• Description: IC XPHASE3 CTLR VR11.1 40-MLPQ
• Manufacturer: International Rectifier
• Series: XPhase3™r

Specifications of IR3523MTRPBF

• Applications: Processor
• Current - Supply: 10mA
• Voltage - Supply: 4.75 V ~ 7.5 V
• Operating Temperature: 0°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: 40-MLPQ
• Ic Function: Dual Output Control IC
• Supply Voltage Range: 4.75V To 7.5V
• Operating Temperature Range: 0°C To +150°C
• Digital Ic Case Style: MLPQ
• No. Of Pins: 40
• Controller Type: XPhase
• Rohs Compliant: Yes
• Package: 40-Lead MLPQ
• Circuit: X-Phase Control IC
• Switch Freq (khz): 250kHz to 1.5MHz
• Pbf: PbF Option Available
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

VOLTAGE LOOP COMPENSATION
The adaptive voltage positioning (AVP) is usually adopted in the computer applications to improve the transient
response and reduce the power loss at heavy load. Like current mode control, the adaptive voltage positioning
loop introduces extra zero to the voltage loop and splits the double poles of the power stage, which make the
voltage loop compensation much easier.
Adaptive voltage positioning lowers the converter voltage by R
the converter.
The selection of compensation types depends on the output capacitors used in the converter. For the applications
using Electrolytic, Polymer or AL-Polymer capacitors and running at lower frequency, type II compensation shown
in Figure (a) is usually enough. While for the applications using only ceramic capacitors and running at higher
frequency, type III compensation shown in Figure 21(b) is preferred.
For applications where AVP is not required, the compensation is the same as for the regular voltage mode
control. For converter using Polymer, AL-Polymer, and ceramic capacitors, which have much higher ESR zero
frequency, type III compensation is required as shown in Figure 21(b) with R
Type II Compensation for AVP Applications
Determine the compensation at no load, the worst case condition. Choose the crossover frequency fc between
1/10 and 1/5 of the switching frequency per phase. Assume the time constant of the resistor and capacitor across
the output inductors matches that of the inductor, and determine R
C
respectively.
C
A ceramic capacitor between 10pF and 220pF is usually enough.
E
CP1
are the equivalent inductance of output inductors and the equivalent capacitance of output capacitors
is optional and may be needed in some applications to reduce the jitter caused by the high frequency noise.
VO+
VDRP
Page 28 of 37
RFB
RDRP
(a) Type II compensation
C
R
CP
CP
=
=
2 (
10
V
I
π
*
∗
VDAC
∗
FB
FB
R
RCP
f
1
L
C
Figure 17 - Voltage loop compensation network
CP
+
E
)
2
2 (
∗
∗
+
-
CCP1
π
C
L
E
*
E
EAOUT
∗
f
C
C
*
E
CCP
C
∗
*
R
R
FB
C
)
∗
2
EAOUT
5
VO+
VDRP
RFB1
O
*I
(b) Type III compensation
O,
CP
where R
RFB
RDRP
CFB
CDRP
and C
DRP
O
CP
VDAC
is the required output impedance of
FB
from (23) and (24), where L
and C
RCP
+
-
CCP1
DRP
EAOUT
removed.
CCP
June 20, 2008
(23)
(24)
EAOUT
IR3523
E
and