Wide Range Current Mirror Using Segmented Transistor Pairs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current mirrors are designed for a narrow range of input currents and fail to accurately reproduce input currents across a wide range, such as from 1 microampere to 1 milliampere.
Innovation Solution
The design includes pairs of transistors and resistors configured to operate in weak and strong inversion modes, allowing the current mirror to accurately replicate input currents over a wide range by using n-type and p-type metal oxide semiconductor field effect transistors or bipolar junction transistors, with resistors connected across the transistors to manage current flow and maintain stability across varying current levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current mirror is designed for a narrow range of input currents, then it can accurately reproduce currents within that specific range, but it fails to accurately reproduce currents across a wide range
Solution Approach 1:
The current mirror is divided into multiple parallel current mirror circuits, each optimized for a specific current range. Each circuit includes transistors and resistors configured to operate effectively in its designated range, allowing the overall system to handle a wide spectrum of input currents with high accuracy in each segment
Solution Approach 2:
The circuit dynamically adapts its operating mode based on the input current level. Transistors switch between weak inversion and strong inversion modes depending on the current magnitude, enabling the current mirror to maintain accuracy across varying current conditions by automatically adjusting its internal operating characteristics
2Measurement precision
If transistors operate in weak inversion mode, then the current mirror can handle low current ranges accurately, but it cannot maintain stability at higher current levels
Solution Approach 1:
The circuit changes the operating parameters of transistors based on current levels. At low currents, transistors operate in weak inversion mode for high precision. As current increases, the circuit transitions transistors to strong inversion mode, changing their electrical characteristics to maintain stability and prevent excessive voltage conditions at higher current levels
3Stability of the object's composition
If transistors operate in strong inversion mode, then the current mirror can handle high current ranges, but it loses accuracy at low current levels
Solution Approach 1:
The current mirror system is segmented into multiple parallel circuits, where each circuit is optimized for specific current ranges. Low-current circuits use transistors configured for weak inversion operation to maintain accuracy at low levels, while high-current circuits use transistors optimized for strong inversion mode, ensuring both accuracy and stability in their respective ranges without compromise
Data Source
AI summary
A current mirror includes a first pair of transistors, wherein gates of the first pair of transistors are connected together, and a second pair of transistors coupled to the first pair of transistors. Gates of the second pair of transistors are connected together. A first resistive device is coupled across a drain and a source of one of the transistors of the second pair of transistors. A second resistive device is coupled across a drain and a source of the other transistor of the second pair of transistors. The first pair of transistors are configured to operate in weak inversion at an input current to the current mirror within a first current range and the second pair of transistors are configured to operate in strong inversion at an input current within a second current range.