IR3508ZMPBF International Rectifier, IR3508ZMPBF Datasheet - Page 11

• Manufacturer Part Number: IR3508ZMPBF
• Description: The IR3508ZM Phase IC combined with any IR XPhase3 Control IC provides a full featured and flexible way to implement a power solution for the latest high performance CPUs and ASICs.
• Manufacturer: International Rectifier

Specifications of IR3508ZMPBF

• Package: 20-Lead MLPQ
• Circuit: X-Phase Phase IC
• Pbf: PbF Option Available

share loop is much slower than that of the voltage loop and the two loops do not interact. For proper current sharing the
output of current sense amplifier should not exceed (VCCL-1.4V) under all operating condition.
IR3508Z THEORY OF OPERATION
Block Diagram
The Block diagram of the IR3508Z is shown in Figure 5, and specific features are discussed in the following
sections.
Tri-State Gate Drivers
The gate drivers are design to provide a 2A source and sink peak current (Bottom gate driver can sink 4A). An
adaptive non-overlap circuit monitors the voltage on the GATEH and GATEL pins to prevent MOSFET shoot-
through current and minimizing body diode conduction. The non-overlap latch is added to eliminate erroneous
triggering caused by the switching noise. A fault condition is communicated to the phase IC via the control IC’s error
amplifier without an additional dedicated signal line. The error amplifier’s output is driven low in response to any
fault condition detected by the controller, such as VCCL under voltage or output overload, disabling the phase IC
and activating Body Braking
drives the bottom gate output low. This tri-state operation prevents negative inductor current and negative output
voltage during power-down.
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PHSIN
DACIN
CLKIN
LGND
IOUT
VCC
EAIN
SHARE_ADJ
DACIN
(LOW=OPEN)
DEBUG OFF
DACIN-SHARE_ADJ
EAIN
PWM COMPARATOR
CALIBRATION
CALIBRATION
+
-
TM
RMPOUT
SHARE
ADJUST
AMPLIFIER
PHSIN
-
+
. The IR3508Z Body Braking
VCC
VCCL
100mV
200mV
0.8V
+
-
BODY BRAKING
COMPARATOR
EAIN
PWM RAMP
GENERATOR
OVP
COMPARATOR
-
+
-
+
3K
VCCL
NEGATIVE CURRENT
COMPARATOR
D
CLK
Q
PWM LATCH
RESET
DOMINANT
PSI_SY NC
PSI_SY NC
PWM RESET
RESET
DOMINANT
PWM_CLK
ANTI-BIAS
LATCH
NEGATIVE
CURRENT
LATCH
-
+
Q
Figure 5: Block diagram
Q
D
CLK
PSI_SY NC
CLK
R
S
.
.
D
Q
Q
DFFRSH
U183
Q
.
CLK
IROSC
D
PHASE DELAY DFF
VCCL
CLK
D
GATEL NON-
OVERLAP
LATCH
PWMQ
DACIN
GATEH NON-
OVERLAP
LATCH
8CLK
Q
Q
SET
DOMINANT
TM
SET
DOMINANT
Q
Q
CLK
SYNCHRONOUS RECTIFICATION
DISABLE COMPARATOR
D
PSI_SYNC
R
R
(CLKIN for 1-PHASE)
S
S
+
IROSC
comparator detects the low signal at the EAIN and
VCCL
+
CSAOUT
-
+
GATEH NON-
OVERLAP
COMPARATOR
GATEL NON-
OVERLAP
COMPARATOR
PHSIN
X
0.75
.
.
.
CURRENT SENSE
AMPLIFIER
.
-
+
+
-
GATEL
DRIVER
X32.5
.
1V
1V
CALIBRATION
GATEH
DRIVER
-
+
PSI
COMPARATOR
610mV
510mV
DEBUG
COMPARATOR
-
+
0.15V
+
-
1V
500K
Jan 09, 2009
IR3508Z
GATEH
BOOST
SW
VCCL
GATEL
PGND
CSIN-
CSIN+
PSI
PHSOUT