VR11.1, 4-Phase PWM Controller with
Phase Dropping, Droop Disabled and
Load Current Monitoring Features
The ISL6334D controls voltage regulator by driving up to 4
interleaved synchronous-rectified buck channels in parallel.
This multiphase architecture results in multiplying channel
ripple frequency and reducing input and output ripple currents.
Lower ripple results in fewer components, lower cost, reduced
power dissipation, and smaller implementation area.
Microprocessor loads can generate load transients with
extremely fast edge rates and requires high efficiency at light
load. The ISL6334D utilizes Intersil’s proprietary Active
Pulse Positioning (APP), Adaptive Phase Alignment (APA)
modulation scheme, active phase adding and dropping to
achieve and maintain the extremely fast transient response
with fewer output capacitors and high efficiency from light to
The ISL6334D is designed to be completely compliant with
Intel VR11.1 specifications. It accurately reports the load
current via IMON pin to the microprocessor, which sends an
active low PSI# signal to the controller at low power mode.
The controller then enters 1- or 2-phase operation with diode
emulation option to reduce magnetic core and switching
losses, yielding high efficiency at light load. After the PSI#
signal is de-asserted, the dropped phase(s) are added back
to sustain heavy load transient response and efficiency.
The ISL6334D senses the output current continuously by
utilizing patented techniques to measure the voltage across the
dedicated current sense resistor or the DCR of the output
inductor. Current sensing circuits also provide the needed
signals for channel-current balancing, average overcurrent
protection and individual phase current limiting. An NTC
thermistor’s temperature is sensed via the TM pin and internally
digitized for thermal monitoring and for integrated thermal
compensation of the current sense elements.
A unity gain, differential amplifier is provided for remote voltage
sensing and completely eliminates any potential difference
between remote and local grounds. This improves regulation
and protection accuracy. The threshold-sensitive enable input is
available to accurately coordinate the start-up of the ISL6334D
with any other voltage rail. Dynamic-VID™ technology allows
seamless on-the-fly VID changes. The offset pin allows
accurate voltage offset settings that are independent of VID
October 29, 2008
• Intel VR11.1 Compliant with Droop Disabled
• Proprietary Active Pulse Positioning (APP) and Adaptive
Phase Alignment (APA) Modulation Scheme
• Proprietary Active Phase Adding and Dropping For High
Light Load Efficiency
• Precision Multiphase Core Voltage Regulation
- Differential Remote Voltage Sensing
- ±0.5% Closed-loop System Accuracy Over Load, Line
- Bi-directional, Adjustable Reference-Voltage Offset
• Precision Resistor or DCR Differential Current Sensing
- Accurate Channel-Current Balancing
- Accurate Load Current Monitoring via IMON Pin
• Microprocessor Voltage Identification Input
- Dynamic VID™ Technology for VR11.1 Requirement
- 8-Bit VID, VR11 Compatible
• Average Overcurrent Protection and Channel Current Limit
• Precision Overcurrent Protection on IMON Pin
• Thermal Monitoring and Overvoltage Protection
• Integrated Programmable Temperature Compensation
• Integrated Open Sense Line Protection
• 1- to 4-Phase Operation, Coupled Inductor Compatibility
• Adjustable Switching Frequency up to 1MHz Per Phase
• Package Option
- QFN Compliant to JEDEC PUB95 MO-220 QFN - Quad
Flat No Leads - Product Outline
• Pb-Free (RoHS Compliant)
1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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Copyright Intersil Americas Inc. 2008. All Rights Reserved
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