Time-Interleaved Current Feedback Droop for Multiphase Buck Converters

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Solution Overview

Problem

Conventional multiphase buck converters face issues with temperature-dependent current sensing and increased power consumption due to the need for multiple current sense amplifiers, leading to complex and costly circuitry and reduced efficiency in load transient response.

Innovation Solution

Implementing a time-interleaved current-feedback droop function that uses interphase and intraphase current averaging methods to determine a droop voltage, reducing the number of active and passive components and eliminating temperature dependence, while sharing a tracking amplifier across phases to minimize power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple current sense amplifiers are used for temperature-dependent current sensing in multiphase buck converters, then current measurement accuracy is improved, but power consumption increases and circuit complexity increases

Engineering Contradiction:

Improvecurrent measurement accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent merges the current sensing function into the existing control circuitry by using the control amplifier to sense both voltage and current through its feedback network. The current sense resistor is integrated into the switch node, and the amplifier's feedback path is used to sense the voltage across this resistor, eliminating the need for separate current sense amplifiers for each phase.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The control amplifier is made multi-functional by using it for both voltage regulation and current sensing. The feedback network is configured so that the same amplifier that regulates output voltage also senses the voltage across the current sense resistor, thereby performing both voltage control and current measurement functions with a single amplifier.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple current sense amplifiers are used for current sensing in multiphase buck converters, then current measurement accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvecurrent measurement accuracyVSAvoidcircuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If conventional current sensing methods are used in multiphase buck converters, then current measurement is achieved, but temperature dependence affects measurement accuracy

Engineering Contradiction:

Improvecurrent measurement accuracyVSAvoidtemperature dependence

Core Design Contradiction:

Measurement precisionVSTemperature

Solution Approach 1:

The patent uses feedback through the control amplifier to sense the voltage across the current sense resistor. This feedback mechanism allows the system to continuously monitor and compensate for temperature-dependent variations in the sense resistor value, as the amplifier adjusts its output to maintain the correct feedback voltage despite changes in resistor characteristics due to temperature.

Inventive Principle:

Principle #23Feedback

4Measurement precision

If additional amplifiers and thermal regulation components are added to improve current sensing accuracy, then measurement precision is improved, but power consumption increases

Engineering Contradiction:

Improvecurrent sensing accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10439497B2Time-interleaved current feedback droop function for multiphase buck converters

Publication Date: 2019.10.08 TEXAS INSTRUMENTS INC

AI summary

Methods and apparatus for providing a time-interleaved current-feedback droop function for multiphase buck converters. An example method includes outputting a first control signal to enable a first set of switches corresponding to a first voltage of a first phase from a multiphase converter, the first phase included in a plurality of phases; enabling a first current associated with the first phase to be measured by a sample and hold circuit associated with the first phase; sampling the first current; holding the first current, the first current based on a load current for the first phase of the multiphase converter; and outputting a droop voltage based on a plurality of currents corresponding to the plurality of phases of the multiphase converter, the plurality of currents including the load current for the first phase.