ISL6561 Datasheet, PDF (1/26 Pages) Intersil Corporation – Multi-Phase PWM Controller with Precision Rds(on) or DCR Differential Current Sensing for VR10.X Application

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Data Sheet
May 12, 2005
ISL6561
FN9098.5
Multi-Phase PWM Controller with
Precision r_DS(ON) or DCR Differential
Current Sensing for VR10.X Application
The ISL6561 controls microprocessor core voltage regulation
by driving up to 4 synchronous-rectified buck channels in
parallel. Multi-phase buck converter architecture uses
interleaved timing to multiply channel ripple frequency and
reduce input and output ripple currents. Lower ripple results in
fewer components, lower component cost, reduced power
dissipation, and smaller implementation area.
Microprocessor loads can generate load transients with
extremely fast edge rates. The ISL6561 features a high
bandwidth control loop and ripple frequencies of >4MHz to
provide optimal response to the transients.
Today’s microprocessors require a tightly regulated output
voltage position versus load current (droop). The ISL6561
senses current by utilizing patented techniques to measure
the voltage across the on resistance, r_DS(ON), of the lower
MOSFETs or DCR of the output inductor during the lower
MOSFET conduction intervals. Current sensing provides the
needed signals for precision droop, channel-current
balancing, and overcurrent protection.
The accuracy of the current-sensing method is enhanced by
the ISL6561’s temperature compensation function. Droop
accuracy can be affected by increasing r_DS(ON) or DCR with
elevated temperature. The ISL6561 uses an internal
temperature-sensing element to provide programmable
temperature compensation. Correctly applied, temperature
compensation can completely nullify the effect of r_{DS(ON) or}
DCR temperature sensitivity.
A unity gain, differential amplifier is provided for remote
voltage sensing. Any potential difference between remote
and local grounds can be completely eliminated using the
remote-sense amplifier. Eliminating ground differences
improves regulation and protection accuracy. The threshold-
sensitive enable input is available to accurately coordinate
the start up of the ISL6561 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. The ISL6561
uses 5V bias and has a built-in shunt regulator to allow 12V
bias using only a small external limiting resistor.
Features
• Precision Multi-Phase Core Voltage Regulation
- Differential Remote Voltage Sensing
- ±0.5% System Accuracy Over Life, Load, Line and
Temperature
- Adjustable Reference-Voltage Offset
• Precision r_DS(ON) or DCR Current Sensing
- Integrated Programmable Temperature Compensation
- Accurate Load-Line Programming
- Accurate Channel-Current Balancing
- Differential Current Sense
- Low-Cost, Lossless Current Sensing
• Internal Shunt Regulator for 5V or 12V Biasing
• Microprocessor Voltage Identification Input
- Dynamic VID™ technology
- 6-Bit VID Input
- 0.8375V to 1.600V in 12.5mV Steps
• Threshold-Sensitive Enable Function for synchronizing
with driver POR
• Overcurrent Protection
• Overvoltage Protection
- No Additional External Components Needed
- OVP Pin to drive opitional Crowbar Device
• 2, 3, or 4 Phase Operation
• Greater Than 1MHz Operation (> 4MHz Ripple)
• Pb-free Available (RoHS Compliant)
• QFN Package Option
- QFN Compliant to JEDEC PUB95 MO-220 QFN - Quad
Flat No Leads - Product Outline
- QFN Near Chip Scale Package Footprint; Improves
PCB Efficiency, Thinner in Profile
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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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