Temperature Compensation Circuit for Constant Current Stability
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Solution Overview
Problem
Existing constant current source circuits fail to maintain a constant current due to temperature variations in resistors with negative temperature coefficients, as they lack effective compensation mechanisms.
Innovation Solution
A device with temperature compensation that includes a constant voltage provider and a compensating load with a resistor having a negative temperature coefficient, coupled in series or parallel with a compensating unit having a positive temperature coefficient, to stabilize the current by adjusting the resistive values of both components in response to temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resistor with negative temperature coefficient is used to transform constant voltage into current, then the current can be maintained constant under ideal conditions, but the current fluctuates when temperature varies
Solution Approach 1:
The patent applies parameter changes by introducing a compensating unit with positive temperature coefficient to counterbalance the negative temperature coefficient of the resistor. As temperature varies, the compensating unit's resistance changes in the opposite direction, maintaining the overall current stability. This resolves the contradiction by dynamically adjusting resistance parameters in response to temperature changes.
Solution Approach 2:
The patent implements feedback through the compensating unit that senses temperature-induced resistance changes and automatically adjusts to compensate. The compensating unit forms a feedback mechanism where the temperature coefficient mismatch is corrected, ensuring the current remains constant despite temperature variations.
2Reliability
If a compensating load with positive temperature coefficient is used to compensate for temperature variation, then current stability improves, but the device complexity increases
Solution Approach 1:
The patent merges the compensating unit with the existing resistor to form an integrated compensating load. By combining these elements into a unified structure, the patent achieves current stability without proportionally increasing device complexity. The merged structure allows the compensating function to be embedded within the existing circuit topology.
Solution Approach 2:
The compensating unit serves multiple functions: it compensates for temperature variations, maintains current stability, and integrates with the existing constant voltage provider and resistor. This multi-functionality reduces the need for separate compensation circuits, thereby limiting the increase in device complexity while achieving reliability improvement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures a substantially constant current is maintained across a range of temperatures, allowing for adjustment of the temperature coefficient to meet various application requirements by controlling the size and values of the transistors and resistors.
Implementation Method 1
a compensating unit, having a positive temperature coefficient and coupled in series or in parallel to the resistor, for compensating a resistance variation of the resistor for a temperature variation
Data Source
AI summary
A device, having temperature compensation, includes a constant voltage provider for providing a constant voltage; and a compensating load coupled to the constant voltage provider for providing a resistive load to transform the constant voltage into a substantially constant current. The compensating load contains a resistor, having a negative temperature coefficient and coupled to the constant voltage; and a compensating unit, having a positive temperature coefficient and coupled in series to the resistor, for compensating a resistance variation of the resistor for a temperature variation.