Multiphase 101

In today’s computing environment, CPUs, FPGAs, ASICs and even peripherals are growing increasingly complex and, consequently, so do their power delivery requirements. To handle the higher demands, multiphase regulators are becoming increasingly common on motherboards in many areas of computing--from laptops and tablets to servers and Ethernet switches. Designing with these regulators is more challenging than using conventional switchers and linear regulators, but the benefits of multiphase outweigh the complexity for high-performance power applications. TI’s Multiphase Buck portfolio includes Intel CPU core regulators, as well as other ASIC/Processor/FPGA Multiphase Buck regulators, with or without interfaces to the processor.

This training series is built around the video instruction of TI’s own application engineer, Carmen Parisi, and is designed to provide the necessary equations and guidance to get a new multiphase design up and running and ready for validation. After an overview of multiphase benefits, an in-depth design example of a multiphase buck regulator for an ASIC core rail is presented.

1. An Introduction to Multiphase Buck Regulators

The below introductory section features a video briefly discussing what exactly multi-phase buck regulators are, what applications they're suited for, and some of the challenges associated with implementing them. Additionally, the listed resources dive a little deeper into the topics covered in the video, providing further instruction in the beginning of your multiphase journey. 

White Papers 

Benefits of a multiphase buck converter

Choosing the Right Variable Frequency Buck Regulator Control Strategy


Voltage regulator features – inside the black box


# Title Duration
1.1 An Introduction to Multiphase Buck Regulators
Carmen Parisi gives an introduction to Multiphase Buck Regulators.
1.2 PowerStack(tm) Packaging Technology Overview
A deeper look into the construction of TI’s Smart Power Stages and how packaging can enhance circuit performance
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2. Designing with Multiphase

In designing with multiphase, Carmen works through a six-phase design for powering the core voltage of a networking ASIC, Marketing Manager George Lakkas explains why multiphase converters are ideal for high currents, and TI engineers blog about common concerns and use contexts.


How important is phase-to-phase current balance in multiphase converters?

Powering the Intel® Arria 10 GX FPGA with a PMBus Multiphase Buck DC/DC Converter

Powering high-current Broadcom networking processors in Ethernet switches

Application Notes

Multiphase Buck Design From Start to Finish (Part 1)

Two Parallel, Synchronous Four-Switch Buck-Boost Converters With Master Slave Method for Higher Power

Two Parallel, Synchronous, Four-Switch Buck-Boost Converters With Droop Method for Higher Power

D-CAP+TM Control for Multiphase Step-Down Voltage Regulators for Powering Microp

Reference Designs

PMBus Power System for Enterprise Ethernet Switches Reference Design


# Title Duration
2.1 Multiphase Buck Regulator Design: A Case Study
Carmen Parisi gives a detailed look into the multiphase buck design process.
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3. Testing in the Lab

In testing in the lab, Carmen takes a six phase buck regulator through basic validation testing in the lab with plenty of tips and waveforms shared. Let Carmen show you how to test transient response, input and output ripple, phase stability, and thermal performance. Additionally, TI engineers blog about various lab tricks related to multiphase devices.


How you measure ripple can make you or break you

Powering Intel’s Xeon D SoC in servers, storage and switches

An introduction to the D-CAP+™ modulator and its real world performance

The D-CAP+™ Modulator: Evaluating the small-signal robustness


# Title Duration
3.1 Testing a Multiphase Regulator in the Lab
Carmen Parisi explains how to test a multiphase buck regulator in the lab.
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