IR3502MTRPBF International Rectifier, IR3502MTRPBF Datasheet - Page 9

• Manufacturer Part Number: IR3502MTRPBF
• Description: IC XPHASE3 CONTROLLER 32-MLPQ
• Manufacturer: International Rectifier
• Series: XPhase3™r

Specifications of IR3502MTRPBF

• Applications: Processor
• Current - Supply: 8mA
• Voltage - Supply: 8 V ~ 16 V
• Operating Temperature: 0°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: 32-MLPQ
• Package: 32-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
• Other names: IR3502MTRPBFTR

SYSTEM THEORY OF OPERATION
System Description
The system consists of one control IC and a scalable array of phase converters, each requiring one phase IC. The
control IC communicates with the phase ICs using three digital buses, i.e., CLOCK, PHSIN, PHSOUT and three
analog buses, i.e., VDAC, EA, IIN. The digital buses are responsible for switching frequency determination and
accurate phase timing control without any external component. The analog buses are used for PWM control and
current sharing among interleaved phases. The control IC incorporates all the system functions, i.e., VID, CLOCK
signals, error amplifier, fault protections, current monitor, etc. The Phase IC implements the functions required by
each phase of the converter, i.e., the gate drivers, PWM comparator and latch, over-voltage protection, Phase
disable circuit, current sensing and sharing, etc.
PWM Control Method
The PWM block diagram of the XPhase3
with trailing edge modulation is used. A high-gain wide-bandwidth voltage type error amplifier in the control IC is
used for the voltage control loop. Input voltage is sensed in phase ICs and feed-forward control is realized. The
PWM ramp slope will change with the input voltage and automatically compensate for changes in the input voltage.
The input voltage can change due to variations in the silver box output voltage or due to the wire and PCB-trace
voltage drop related to changes in load current.
Frequency and Phase Timing Control
The oscillator is located in the control IC and the system clock frequency is programmable from 250kHz to 9MHZ by
an external resistor. The control IC system clock signal CLKOUT is connected to CLKIN of all the phase ICs. The
phase timing of the phase ICs is controlled by the daisy chain loop, where control IC phase clock output PHSOUT is
Page 9 of 39
IVSETPT
VDRP
AMP
CONTROL IC
CLOCK GENERATOR
+
-
REMOTE SENSE
AMPLIFIER
+
-
IROSC
ERROR
AMPLIFIER
Compensation
Thermal
VDAC
VDAC
+
-
VN
VSETPT
IMON
VDRP
IIN
PHSOUT
PHSIN
VO
VDAC
LGND
EAOUT
FB
CLKOUT
RVSETPT
RTHRM
RCOMP
CCOMP
RFB1
CFB
RDRP1
CDRP
GATE DRIVE
VOLTAGE
RFB
RDRP
Figure 3 System Block Diagram
TM
architecture is shown in Figure 3. Feed-forward voltage mode control
PHSOUT
PHSOUT
PHSIN
CLKIN
ISHARE
DACIN
EAIN
ISHARE
DACIN
CLKIN
PHSIN
EAIN
3K
3K
CLK
D
SHARE ADJUST
ERROR AMPLIFIER
CLK
D
SHARE ADJUST
ERROR AMPLIFIER
Q
PWM
COMPARATOR
Q
PWM
COMPARATOR
+
-
+
-
RAMP
DISCHARGE
CLAMP
RAMP
DISCHARGE
CLAMP
ENABLE
ENABLE
1
-
1
VID6
-
VID6
+
VID6
VID6
+
VID6
VID6
-
+
-
+
+
-
+
-
PHASE IC
PHASE IC
2
2
PWM LATCH
PWM LATCH
BODY
BRAKING
COMPARATOR
BODY
BRAKING
COMPARATOR
DOMINANT
D
CLK
DOMINANT
RESET
D
CLK
RESET
VID6
VID6
VID6
VID6
DFFRH
Q
Q
U248
Q
Q
DFFRH
U246
+
+
+
+
CURRENT
SENSE
AMPLIFIER
CURRENT
SENSE
AMPLIFIER
OFF
OFF
OFF
VID6
OFF
VID6
VID6
+
-
VID6
+
-
CSIN-
PSI
CSIN-
VCC
VCCH
GATEH
SW
VCCL
GATEL
PGND
PSI
CSIN+
VCC
VCCH
GATEH
SW
VCCL
GATEL
PGND
CSIN+
CCS
CCS
RCS
RCS
July 28, 2009
CBST
CBST
IR3502
COUT
PSI
PSI
VIN
VOSNS+
VOUT
GND
VOSNS-