Current Mirror Output Circuit for Stable Source-Sink Current

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Solution Overview

Problem

Existing output circuits face challenges in minimizing the influence of other circuit parts on the output terminal, leading to inefficiencies and interference in providing a stable output current.

Innovation Solution

The output circuit employs a first current mirror and a first pass transistor, directly and permanently connected to the output terminal, with a series circuit configuration that minimizes the presence of additional transistors, diodes, or resistors, allowing for a reduced influence of other circuit parts and enabling the output circuit to function as a current source or sink with minimal external control signals or bias voltages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple transistors, diodes, or resistors are present in the coupling path between delivering terminal and output terminal, then the circuit can provide more control functions, but the influence of other circuit parts on the output terminal increases

Engineering Contradiction:
Improvecontrol functionsVSAvoidinfluence of other circuit parts
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes unnecessary intermediate components (transistors, diodes, resistors) from the coupling path between the delivering terminal and output terminal. By taking out these extraneous elements, the circuit achieves direct coupling that eliminates their harmful influence on the output terminal while preserving essential control functions through the remaining optimized component structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the circuit into distinct functional blocks: the delivering terminal stage, the output terminal stage, and the control stage. This segmentation allows the output terminal to be directly coupled to the delivering terminal without interference from intermediate components, while control functions are implemented through separate control signals applied to specific transistors in the segmented architecture.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If a direct and permanent connection is made between current mirror and pass transistor, then the output current stability is improved, but the device complexity increases

Engineering Contradiction:
Improveoutput current stabilityVSAvoidconnection structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent merges the current mirror and pass transistor into a tightly integrated unit with direct and permanent connections. This merging eliminates intermediate coupling elements and creates a unified functional block that ensures stable output current by maintaining consistent electrical connections between the current mirror's output and the pass transistor's control terminal, while the overall device complexity is managed through this consolidated architecture.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If the output circuit uses a simple configuration with minimal components, then the influence of other circuit parts is reduced, but the ability to handle high voltages and switch between source and sink modes may be compromised

Engineering Contradiction:
Improveinfluence of other circuit partsVSAvoidvoltage handling and mode switching
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent implements a universal output circuit configuration where the pass transistor and current mirror structure can operate in multiple modes (current source and current sink) and handle high voltages. The direct coupling between delivering terminal and output terminal maintains simplicity and reduces harmful influences, while the transistor's inherent capability and proper biasing enable versatile voltage handling and mode switching without adding complex external components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3352042B1Output circuit and method for providing an output current
Publication Date: 2021.04.07 AUSTRIAMICROSYSTEMS AG
  • EP3352042B1 patent drawingFigure 1A~1B
  • EP3352042B1 patent drawingFigure 2A~2B
  • EP3352042B1 patent drawingFigure 2C

AI summary

An output circuit comprises an output terminal (11), a first current mirror (12), a first pass transistor (13) and a first delivering terminal (14) coupled via the first current mirror (12) and the first pass transistor (13) to the output terminal (11).