IR3529MTRPBF International Rectifier, IR3529MTRPBF Datasheet - Page 14

• Manufacturer Part Number: IR3529MTRPBF
• Description: IC CTRL XPHASE CPU/ASIC 20-MLPQ
• Manufacturer: International Rectifier
• Series: XPhase3™r

Specifications of IR3529MTRPBF

• Applications: Processor
• Current - Supply: 2mA
• Voltage - Supply: 8 V ~ 16 V
• Operating Temperature: 0°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: *
• Package: 20-Lead MLPQ
• Circuit: X-Phase Phase IC
• Iout (a): 4.0A Gate Driver
• Pbf: PbF Option Available
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: IR3529MTRPBFTR

Turbo Modulator
The turbo functionality is included in IR3529 to improve the transient performance of the system with reduced
output capacitance. The turbo modulator consists of a comparator that monitors the EAIN signal and its filtered
version. The modulator turns on the phase when EAIN reaches 260 mV above its filtered version and turns off
when EAIN reaches its peak value. This action helps to achieve an improved transient response with lesser output
capacitors thereby reducing the overall system cost.
Cycle-by-cycle over current protection
IR3529 incorporates the OCSET function to improve the transient response when the load repetition rate is close
to the switching frequency. When a significantly high load current is cycled at the switching frequency of the multi-
phase VR, the phases that are synchronized with the load current will experience an incremental change in the
duty ratio while the other phases will experience a decrease in the duty ratio from the nominal value. This in turn
will lead to huge inductor currents in the phases that are synchronized with the load and thereby saturating the
inductor core. Eventually, this will lead to an OVP condition or failure of the high-side MOSFET.
In IR3529, the problem due to high repetition rate of the load is addressed by high side current sensing and
thereby providing cycle-by-cycle over current protection. The over current threshold is programmed with an
external resistor (R
monitors the voltage across the on-resistance (R
pulse if the sensed voltage reaches the over current threshold. This helps to reduce the deviation at the error
amplifier output thereby improving the transient response.
Debugging Mode
Emulated Bootstrap Diode
IR3529 integrates a PFET to emulate the bootstrap diode. If two or more top MOSFETs are to be driven at higher
switching frequency, an external bootstrap diode connected from VCCL pin to BOOST pin may be needed.
If the CSIN+ pin is pulled up to VCCL voltage, IR3529 enters into debugging mode. Both drivers are pulled low
and IOUT output is disconnected from the current share bus, which isolates this phase IC from other phases.
However, the phase timing from PHSIN to PHSOUT does not change.
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OCSET
) connected to the OCSET pin with a sink current of 200 µA. The OCSET comparator
D_PWM LATCH
PSI_SYNC
PSI
CLK
Figure 7: PSI assertion.
8 PHSIN Delay
DS, ON
) of the high-side MOSFET and terminates the high side
February 12, 2010
IR3529