Adaptive Current Mirror Circuit for Temperature-Shaped Output Current
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Solution Overview
Problem
Current mirror circuits in electronics face challenges in controlling the output current's relationship with temperature variations, making it difficult to maintain consistent performance across a range of temperatures.
Innovation Solution
An adaptive current mirror circuit is introduced, comprising a current generator circuit and a compensation circuit that adjusts the overdrive voltage based on temperature, using device pairs to control the conductance of the output device, allowing for various temperature-current profiles such as increasing, decreasing, or remaining constant with temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional current mirror circuit is used, then the circuit structure is simple, but the output current cannot maintain consistent performance across temperature variations
Solution Approach 1:
The current mirror circuit is segmented into multiple parallel current mirror branches, each with different transistor size ratios. This segmentation allows the circuit to handle different temperature ranges independently, with each branch optimized for specific temperature conditions, thereby maintaining output current consistency across the full temperature range while keeping individual branch structures relatively simple.
Solution Approach 2:
The patent uses composite transistor configurations with different size ratios arranged in parallel. These composite structures combine the characteristics of transistors with different dimensions to achieve temperature compensation. The composite arrangement allows the circuit to leverage both small-transistor and large-transistor behaviors to maintain consistent output current across temperature variations.
2Reliability
If the transistor size ratio is increased to compensate for temperature effects, then the output current stability improves, but the device complexity and design difficulty increase
Solution Approach 1:
The circuit dynamically adapts to temperature changes by utilizing multiple parallel branches with different transistor size ratios. As temperature varies, the effective contribution of each branch changes, allowing the circuit to automatically adjust its compensation mechanism. This dynamic behavior achieves output current stability without requiring a single complex fixed configuration.
Solution Approach 2:
The patent changes the transistor size ratio parameter across different parallel branches to achieve temperature compensation. By varying this key parameter (W/L ratio) systematically across branches, the circuit creates a set of current mirrors with different temperature coefficients. The combination of these branches with different parameters results in overall temperature-insensitive output current.
3Adaptability or versatility
If a single current mirror branch is used, then the device complexity is low, but the adaptability to different temperature conditions is insufficient
Solution Approach 1:
The current mirror circuit is divided into multiple parallel branches, each segment optimized for specific temperature conditions. This segmentation enables the circuit to cover a wide temperature range by having different branches become dominant at different temperatures, achieving high adaptability while keeping each individual branch relatively simple.
Solution Approach 2:
Each current mirror branch serves multiple functions: it provides current mirroring for its optimized temperature range and also contributes to overall temperature compensation. The parallel structure allows the circuit to universally handle various temperature conditions, with each branch being multi-functional in supporting both local and global current stability.
Data Source
AI summary
An adaptive current mirror circuit for current shaping with temperature is disclosed. The adaptive current mirror includes a current generator circuit configured to receive and input current and generate an output current using the input current and an overdrive voltage. The adaptive current mirror further includes a compensation circuit configured to adjust a value of the overdrive voltage based on temperature.