Temperature-Independent Reference Circuit Using Segmented Sub-Circuits
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Solution Overview
Problem
Conventional integrated circuits are affected by ambient temperature changes in supply voltage, which impacts their performance.
Innovation Solution
A reference circuit comprising a current control sub-circuit, voltage control sub-circuit, and voltage adjustment sub-circuit, where the current control sub-circuit outputs current at a 1:1:n ratio, and the voltage control sub-circuit outputs equal voltages, allowing the voltage adjustment sub-circuit to isolate the output voltage from temperature variations using transistors and resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional supply voltage is used in integrated circuits, then the circuit can operate with simple design, but the supply voltage changes with ambient temperature which affects circuit performance
Solution Approach 1:
The reference circuit is divided into three independent sub-circuits: current control sub-circuit, voltage control sub-circuit, and voltage adjustment sub-circuit. Each sub-circuit performs a specific function in the temperature compensation process, allowing modular design and independent optimization while maintaining overall temperature independence.
Solution Approach 2:
The circuit uses temperature-dependent parameters (Vbe voltage of transistors changes with temperature) to compensate for supply voltage variations. By utilizing the natural temperature characteristics of transistor Vbe and combining it with resistive voltage division, the circuit generates a compensation voltage that counteracts supply voltage changes, achieving temperature-independent output.
2Reliability
If temperature compensation is implemented in the reference circuit, then the output voltage becomes independent of temperature, but the circuit structure becomes more complex
Solution Approach 1:
The voltage control sub-circuit uses the output voltage of the voltage adjustment sub-circuit as feedback to regulate the current through the resistors. This feedback mechanism ensures that the voltage across the resistors (and thus the output voltage) remains stable despite temperature variations or supply voltage changes, achieving automatic temperature compensation.
Solution Approach 2:
The voltage control sub-circuit acts as an intermediary between the current control sub-circuit and the voltage adjustment sub-circuit. It translates current signals into voltage signals and provides the necessary control to maintain equal voltages across the resistors, thereby mediating the temperature compensation process without requiring direct complex interactions between the other sub-circuits.
3Manufacturing precision
If the current control sub-circuit outputs current at ratio 1:1:n, then the voltage control sub-circuit can output equal voltages, but the current distribution requires precise control
Solution Approach 1:
The current control sub-circuit uses a current mirror configuration to copy the reference current to multiple output currents with precise ratio relationships (1:1:n). By replicating the current path and using matched transistors, the circuit achieves accurate current distribution without requiring complex active control mechanisms, simplifying the overall control architecture.
4Productivity
If the voltage output is made independent of temperature, then the integrated circuit performance is optimized, but the voltage adjustment requires additional control mechanisms
Solution Approach 1:
The voltage adjustment sub-circuit automatically adjusts the output voltage to be temperature-independent by utilizing the inherent temperature characteristics of the transistors and resistors. The circuit self-regulates through the natural temperature dependence of Vbe voltage and resistive voltage division, eliminating the need for external temperature sensing or complex control algorithms, thus optimizing performance without excessive control complexity.
Data Source
AI summary
The embodiments of the present disclosure disclose a reference circuit, comprising a current control sub-circuit, a voltage control sub-circuit and a voltage adjustment sub-circuit, wherein the current control sub-circuit outputs current to a first terminal and a second terminal of the voltage control sub-circuit and a first terminal of the voltage adjustment sub-circuit at a ratio of 1:1:n respectively, and the first terminal and the second terminal of the voltage control sub-circuit may cause a voltage at a second terminal of the voltage adjustment sub-circuit to be equal to a voltage at a third terminal of the voltage adjustment sub-circuit upon receiving equal current output by the current control sub-circuit, and the voltage adjustment sub-circuit may adjust a voltage output at an output terminal of the reference circuit to be independent of a temperature when the voltage at the second terminal is equal to the voltage at the third terminal.