IR3510MTRPBF International Rectifier, IR3510MTRPBF Datasheet - Page 17

• 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

are tied together and the voltage on the share bus represents the average inductor current through all the
inductors and is used by the Control IC for voltage positioning and current limit protection
Average Phase Current Share Loop
Current sharing between phases of the converter is achieved by the average current share loop in each phase IC.
The output of the current sense amplifier is compared with average current at the share bus. If current in a phase
is smaller than the average current, the share adjust amplifier of the phase will pull down the starting point of the
PWM ramp thereby increasing its duty cycle and output current; if current in a phase is larger than the average
current, the share adjust amplifier of the phase will pull up the starting point of the PWM ramp thereby decreasing
its duty cycle and output current. The current share amplifier is internally compensated so that the crossover
frequency of the current share loop is much slower than that of the voltage loop and the two loops do not interact.
Average current mode control with limited voltage loop gain
Redundant system requires good current sharing between voltage regulators to reduce electrical/thermal stress on
each module and improve system reliability. There are several current sharing schemes for paralleling voltage
regulators. Most of them require a common current share bus which represents the average current or maximum
current in the paralleling system. But, this common current share bus can cause single point of failure if it is
shorted or opened.
To eliminate single-point failure, but still have good current sharing between paralleled voltage regulators for high-
reliability redundant system application, a novel average current mode control with limited voltage loop gain
scheme can be used.
As shown in Fig. 5, there is no common current share bus between modules. By using limited voltage error gain,
the current reference to the non-inverting input of the current error amplifier is identical for each module, because
each module has the same voltage reference and the same remote sense feedback voltage. The average current
control loop will force each module to carry the same amount of load current.
OCSET
OCSET
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Vref
Vref
Fig. 5 Average current mode control with limited voltage loop gain
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Create Voltage Droop
IREF1
IREF2
Added Current Controller
Added Current Controller
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IR Confidential
PWM
PWM
May 18, 2009
IR3510
Rload