IR3510MTRPBF International Rectifier, IR3510MTRPBF Datasheet - Page 18

• Manufacturer Part Number: IR3510MTRPBF
• Description: IC XPHASE CONTROL 32-MLPQ
• Manufacturer: International Rectifier
• Series: XPhase™r

Specifications of IR3510MTRPBF

• Applications: Processor
• Mounting Type: Surface Mount
• Package / Case: 32-MLPQ
• Package: 32-Lead MLPQ
• Circuit: X-Phase Control IC
• Pbf: PbF Option Available
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -
• Voltage - Supply: -
• Operating Temperature: -
• Other names: IR3510MTRPBFTR

IR3510
The limited voltage loop DC gain controls the voltage droop,
Vdroop = (Kv Ki / Gv) Io,
Where, Kv is the voltage feedback divider factor, Ki is current sense gain, and Gv is the voltage loop DC gain.
The average current mode control also provides constant current limit function for the voltage regulator output,
which is a desired feature for redundant power system.
Input Soft-Start for Hot-Swappable applications
For hot-swappable applications, an input control FET in series with the input voltage is required to prevent the
voltage regulator from pulling down the VIN bus during start-up due to large input caps or pre-loaded output. It
controls the slew rate of the input voltage applied to the voltage regulator. It also keeps the input current within the
limit when the voltage regulator has fault or over-load condition. When OV condition occurs on the voltage
regulator output, the input control FET can be turned off to protect the output load.
A current sense resistor in series with the input FET is used to sense the input current. Once the sense current
exceeds the programmed OC threshold, the input control FET is controlled to run in linear mode to limit the
current, so it has larger power loss and can’t be running for a long period of time. A programmable time delay is
normally implemented to prevent false trigger the input OCP and turns off the input control FET when it is time-out.
ORing Control for Redundant Applications
For redundant system application, multiple voltage regulators can be paralleled to provide fault-tolerant output
voltage for critical load. ORing diode was used to isolate the fault module from the output, but its high power loss
prevents it from being used in low voltage high current application. ORing FET is now commonly used in low
voltage high current application, but its reverse conducting current needs to be limited. The reverse current can be
caused by fault or the mismatch between two paralleled output voltages. Thus, the ORing FET control requires a
reverse current comparator and fast turn-off gate driver.
The Rds(on) of Oring FET is normally used to sense the reverse current. To reduce the conductive power loss, low
Rds(on) FET is preferred for Oring application. Also the reverse current needs to be limited no more than 10% of
rated current, otherwise too much energy would be feedback to the input and may cause input OV. Thus, a very
low offset reverse current comparator and fast turn-off Oring gate driver are required.
IR Confidential
Page 18 of 36
May 18, 2009