ISL6324A
Hybrid SVI/PVI with I²C Monolithic Dual PWM Hybrid Controller Powering AMD SVI Split-Plane and PVI Uniplane Processors

Key Features

• Processor Core Voltage Regulator Features
  
• Configuration Flexibility
• 1- or 2-Phase Operation with Internal Drivers
• 3- or 4-Phase Operation with External PWM Drivers
• Parallel VID (6-bit) Interface Inputs for PVI Mode
• PSI_L Support via Phase Shedding
• Differential Remote Voltage Sensing
• Optimal Processor Core Voltage Transient Response
• Adaptive Phase Alignment (APA)
• Active Pulse Positioning Modulation
  
  
• Processor Core Voltage Regulator and North Bridge Voltage Regulator Shared Features
• Precision Voltage Regulation: ±0.5% System Accuracy Over-Temperature
• Two Wire, AMD Compliant Serial VID Interface Inputs for SVI Mode
• I²C Interface
• Voltage Margining, OVP and PGOOD Trip Levels
• Enhanced PSI_L State Control
• Fully Differential, Continuous DCR Current Sensing
• Accurate Load Line Programming
• Precision Channel Current Balancing for Core
• Overcurrent Protection
• Multi-tiered Overvoltage Protection
• Variable Gate Drive Bias: 5V to 12V
• Simultaneous Digital Soft-Start of Both Outputs
• Selectable Switching Frequency up to 1MHz
• Pb-Free (RoHS Compliant)

Description

The ISL6324A dual PWM controller delivers high efficiency and tight regulation from two synchronous buck DC/DC converters. The ISL6324A supports hybrid power control of AMD processors which operate from either a 6-bit parallel VID interface (PVI) or a serial VID interface (SVI). The dual output ISL6324A features a multi-phase controller to support uniplane VDD core voltage and a single phase controller to power the Northbridge (VDDNB) in SVI mode. Only the multi-phase controller is active in PVI mode to support uniplane VDD only processors.

A precision uniplane core voltage regulation system is provided by a 2-to-4-phase PWM voltage regulator (VR) controller. The integration of two power MOSFET drivers, adding flexibility in layout, reduce the number of external components in the multiphase section. A single phase PWM controller with integrated driver provides a second precision voltage regulation system for the North Bridge portion of the processor. This monolithic, dual controller with integrated driver solution provides a cost and space saving power management solution.

For applications which benefit from load line programming to reduce bulk output capacitors, the ISL6324A features output voltage droop. The multi-phase portion also includes advanced control loop features for optimal transient response to load application and removal. One of these features is highly accurate, fully differential, continuous DCR current sensing for load line programming and channel current balance. Dual edge modulation is another unique feature, allowing for quicker initial response to high di/dt load transients.

The ISL6324A supports Power Savings Mode by dropping phases when the PSI_L bit is set. The number of phases that the ISL6324A will drop to is programmable through an I²C interface. The number of PWM cycles between both dropping phases when entering Power Savings Mode and adding phases when exiting Power Savings Mode is also programmable through the I²C interface.

The ISL6324A I²C interface also allows independent programmable output voltage offset for both the Core and North Bridge regulators. The I²C interface can also be used to set the PGOOD and OVP trip levels for both regulators as well.