IR3500MPBF International Rectifier, IR3500MPBF Datasheet - Page 26

• Manufacturer Part Number: IR3500MPBF
• Description: IC XPHASE3 CONTROL 32-MLPQ
• Manufacturer: International Rectifier
• Series: XPhase3™r

Specifications of IR3500MPBF

• Applications: Processor
• Current - Supply: 6.5mA
• Voltage - Supply: 4.75 V ~ 7.5 V
• Operating Temperature: 0°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: 32-MLPQ
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

During dynamic VID down, OVP may be triggered when output voltage can not follow VDAC voltage change at light
load with large output capacitance. Therefore, over-voltage threshold is raised to 1.73V from VDAC+130mV
whenever dynamic VID is detected and the difference between output voltage and VDAC is more than 50mV, as
shown in Figure 19. The over-voltage threshold is changed back to VDAC+130mV if the difference is smaller than
50mV.
The overall system must be considered when designing for OVP. In many cases the over-current protection of the
AC-DC or DC-DC converter supplying the multiphase converter will be triggered and provide effective protection
without damage as long as all PCB traces and components are sized to handle the worst-case maximum current. If
this is not possible, a fuse can be added in the input supply to the multiphase converter.
Open Remote Sense Line Protection
If either remote sense line VOSEN+ or VOSEN- or both are open, the output of remote sense amplifier (VO) drops.
The IR3500 monitors VO pin voltage continuously. If VO voltage is lower than 200 mV, two separate pulse currents
are applied to VOSEN+ and VOSEN- pins respectively to check if the sense lines are open. If VOSEN+ is open, a
voltage higher than 90% of V(VCCL) will be present at VOSEN+ pin and the output of open line detect comparator
will be high. If VOSEN- is open, a voltage higher than 700mV will be present at VOSEN- pin and the output of open-
line-detect comparator will be high. The open sense line fault latch is set, which pulls error amplifier output low
immediately and shut down the converter. The SS/DEL voltage is discharged and the fault latch can only be reset
by cycling VCCL power.
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VCCLDRV
OUTPUT
VOLTAGE
(VOSEN+)
VCCL UVLO
ROSC/OVP
SS/DEL
VCC
Figure 18 - Over-voltage protection with pre-charging converter output VID + 0.13V <Vo < 1.73V
12V
VCCL+0.7V
VCCL+0.7V
1.73V
VID + 0.13V
VCCL - 1V
0.6V
3.92V (4V-0.08V)
May 18, 2009
IR3500