Floating-Ground Level Shift Circuit for Motor Drive Signals

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Solution Overview

Problem

In motor drive system design, the mismatch between normal and floating ground reference levels necessitates a level shift circuit to facilitate communication between signals with different ground levels, which existing technologies have not adequately addressed.

Innovation Solution

A circuit integrating a controlled switching current source, upper and lower current rectifiers, and an amplifying and shaping circuit on a single substrate, utilizing MOS transistors to shift a fixed ground level to a floating ground level, ensuring phase compatibility between the two reference levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a level shift circuit is designed to convert fixed ground level to floating ground level, then communication between units with different ground references is enabled, but the circuit structure becomes complex requiring multiple current rectifiers and switching components

Engineering Contradiction:

Improvecommunication compatibility between different ground levelsVSAvoidcircuit structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The level shift circuit is divided into three independent current rectifier modules (first upper, second upper, and lower current rectifiers), each handling specific current paths. This segmentation allows the complex ground level conversion to be achieved through modular components working in sequence, making the overall complex function manageable and implementable through standardized building blocks

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The circuit employs a controlled switching current source that dynamically adjusts current flow based on the input signal state. The switching mechanism enables the circuit to adapt its configuration between different ground reference levels, allowing seamless transition between fixed and floating ground modes through controlled current redirection rather than fixed rigid connections

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If multiple current rectifiers and switching components are integrated on a single substrate, then the level shifting function is achieved, but the manufacturing precision requirements increase

Engineering Contradiction:

Improveground level conversion capabilityVSAvoidsubstrate integration precision

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Multiple current rectifier modules and the switching current source are integrated onto a single substrate, consolidating what would otherwise be separate discrete components. This merging reduces the overall system footprint and interconnection complexity, though it necessitates precise manufacturing to ensure proper electrical connections and isolation between the integrated functional blocks

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The circuit design incorporates multiple ground reference points (first ground reference point, second ground reference point, and third ground reference point) at different potential levels. By strategically placing these equipotential regions and ensuring proper electrical isolation, the design accommodates the manufacturing tolerances inherent in substrate integration while maintaining the required ground level differentiation for signal integrity

Inventive Principle:

Principle #12Equipotentiality

3Measurement precision

If the circuit uses controlled switching and multiple current paths, then the ground level shifting accuracy is improved, but the energy consumption increases

Engineering Contradiction:

Improveground level shifting accuracyVSAvoidcircuit energy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The controlled switching current source operates by periodically switching between different current paths based on the input signal transitions. This periodic switching action enables precise ground level tracking by refreshing the current configuration in sync with the signal changes, achieving accurate level shifting while minimizing continuous energy dissipation that would occur with analog buffering approaches

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

Different regions of the circuit are optimized for specific functions: the switching current source region is designed for low-power controlled switching, while the current rectifier regions are optimized for efficient current conversion. This local quality optimization ensures that each part of the circuit consumes minimal energy for its specific function, reducing overall power consumption while maintaining the required ground level shifting accuracy

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11843336B2Circuit for shifting fixed ground level to floating ground level in motor drive system

Publication Date: 2023.12.12 HEFEI AICHUANG MICROELECTRONICS TECHNOLOGY CO LTD

AI summary

Disclosed is a circuit for shifting a fixed ground level to a floating ground level in a motor drive system, including a floating ground high level line, a floating ground output level line, a floating ground low level line, a normal input level line, and a normal ground line that are used for characterizing an application detail. The circuit includes a controlled switching current source, a first upper current rectifier, a second upper current rectifier, a lower current rectifier, and an amplifying and shaping circuit that are integrated on a same substrate.