Dynamic Slew Rate Control for Inverter Drivers

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Solution Overview

Problem

Conventional inverter circuits maintain a constant slew rate across various loading conditions and mode configurations, leading to inefficiencies such as reduced peak power efficiency and a narrower safe operating area for transistors, which can result in circuit malfunctions due to signal bounce caused by parasitic resistances and inductances in packaging components.

Innovation Solution

A method and circuit configuration that dynamically controls the slew rate of an inverter's driver based on detected load magnitude and mode configuration, using a slew rate control module to adjust the slew rate according to load current or voltage comparisons with reference values, and modifying it specifically for dynamic voltage scaling (DVS) and multi-phase modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a constant slew rate is maintained across various loading conditions, then the circuit operation is simplified, but peak power efficiency is reduced and the safe operating area for transistors is narrowed

Engineering Contradiction:
Improvecircuit operation complexityVSAvoidpeak power efficiency
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The patent implements dynamic slew rate control by adjusting the slew rate of the inverter driver based on detected load magnitude and mode configuration. The control module modifies the slew rate in real-time according to operating conditions, transitioning from a static constant slew rate to a dynamic adaptive slew rate, thereby resolving the contradiction between circuit simplicity and power efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the slew rate parameter dynamically based on load conditions and mode configuration. By detecting load magnitude through current or voltage sensing and comparing with reference values, the system adjusts the slew rate parameter to optimize power efficiency under different operating conditions, directly addressing the power efficiency degradation caused by constant slew rate operation.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a constant slew rate is maintained across various loading conditions, then the driver design is simplified, but signal bounce occurs due to parasitic resistances and inductances

Engineering Contradiction:
Improvedriver design complexityVSAvoidsignal bounce
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic slew rate control by adjusting the slew rate of the inverter driver based on detected load magnitude and mode configuration. The control module modifies the slew rate in real-time according to operating conditions, transitioning from a static constant slew rate to a dynamic adaptive slew rate, thereby resolving the contradiction between circuit simplicity and power efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the slew rate parameter dynamically based on load conditions and mode configuration. By detecting load magnitude through current or voltage sensing and comparing with reference values, the system adjusts the slew rate parameter to optimize power efficiency under different operating conditions, directly addressing the power efficiency degradation caused by constant slew rate operation.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a constant slew rate is maintained, then the control mechanism is simplified, but the safe operating area for transistors is narrowed resulting in circuit malfunctions

Engineering Contradiction:
Improvecontrol mechanism complexityVSAvoidtransistor safe operating area
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements a feedback control mechanism where the slew rate control module detects load magnitude through current or voltage sensing, compares the detected value with a reference value, and adjusts the slew rate accordingly. This closed-loop feedback system expands the transistor safe operating area by adapting the slew rate to actual load conditions, preventing circuit malfunctions that occur with constant slew rate operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements dynamic slew rate control by adjusting the slew rate of the inverter driver based on detected load magnitude and mode configuration. The control module modifies the slew rate in real-time according to operating conditions, transitioning from a static constant slew rate to a dynamic adaptive slew rate, thereby resolving the contradiction between circuit simplicity and power efficiency.

Inventive Principle:
Principle #15Dynamics

4Speed

If the slew rate is increased for light loads, then response time is improved, but power efficiency deteriorates under heavy loads

Engineering Contradiction:
Improveresponse timeVSAvoidpower efficiency
Core Design Contradiction:
SpeedVSPower

Solution Approach 1:

The patent changes the slew rate parameter dynamically based on load conditions and mode configuration. By detecting load magnitude through current or voltage sensing and comparing with reference values, the system adjusts the slew rate parameter to optimize power efficiency under different operating conditions, directly addressing the power efficiency degradation caused by constant slew rate operation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamic slew rate control by adjusting the slew rate of the inverter driver based on detected load magnitude and mode configuration. The control module modifies the slew rate in real-time according to operating conditions, transitioning from a static constant slew rate to a dynamic adaptive slew rate, thereby resolving the contradiction between circuit simplicity and power efficiency.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3373434B1Dynamic slew rate control
Publication Date: 2021.07.07 MEDIATEK INC
  • EP3373434B1 patent drawingFigure 1A
  • EP3373434B1 patent drawingFigure 1B
  • EP3373434B1 patent drawingFigure 2

AI summary

An inverter circuit may include an inverter, a driver coupled to the inverter, and a slew rate control module configured to modify a slew rate of the driver. The slew rate may be modified based on a magnitude of a load driven by the inverter circuit. The magnitude of the load driven by the inverter circuit may be indicated by a current representing a load current or a voltage representing an input voltage. The slew rate may also be modified based on a mode configuration of the inverter circuit.