ISL6334 Datasheet, PDF (1/30 Pages) Intersil Corporation – VR11.1, 4-Phase PWM Controller with Light Load Efficiency Enhancement and Load Current Monitoring

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Data Sheet
ISL6334, ISL6334A
February 26, 2008
FN6482.0
VR11.1, 4-Phase PWM Controller with
Light Load Efficiency Enhancement and
Load Current Monitoring Features
The ISL6334, ISL6334A control microprocessor core voltage
regulation 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 ISL6334, ISL6334A 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 full load.
The ISL6334, ISL6334A 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.
Today’s microprocessors require a tightly regulated output
voltage position versus load current (droop). The ISL6334,
ISL6334A 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. The sensed current flows out of FB pin to develop the
precision voltage drop across the feedback resistor for droop
control. 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 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 ISL6334,
ISL6334A 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 setting.
Features
• Intel VR11.1 Compliant
• Proprietary Active Pulse Positioning (APP) and Adaptive
Phase Alignment (APA) Modulation Scheme
• Proprietary Active Phase Adding and Dropping with Diode
Emulation Scheme For High Light Load Efficiency
• Precision Multiphase Core Voltage Regulation
- Differential Remote Voltage Sensing
- ±0.5% Closed-loop System Accuracy Over Load, Line
and Temperature
- Bi-directional, Adjustable Reference-Voltage Offset
• Precision resistor or DCR Differential Current Sensing
- Accurate Load-Line (Droop) Programming
- 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)
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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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