PTAT-CTAT Reference Voltage Circuit for Wide Temperature Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing reference voltage generation circuits fail to maintain a constant voltage within a wide temperature range due to temperature changes and fabrication process variations, particularly at low and high temperatures.
Innovation Solution
A voltage reference circuit utilizing a current generator, PTAT voltage generator, and CTAT voltage generator to generate a reference voltage with approximately zero temperature coefficient, combined with a trim controller to adjust for manufacturing variations, ensuring a stable reference voltage across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex circuits are used to generate reference voltage, then voltage precision can be improved, but temperature stability deteriorates at low and high temperatures
Solution Approach 1:
The reference voltage generation is divided into multiple independent modules: current generator, PTAT voltage generator, and CTAT voltage generator. Each module performs a specific function and can be independently optimized, allowing the system to achieve both precision and temperature stability through modular design.
Solution Approach 2:
The circuit utilizes parameters with opposite temperature coefficients (PTAT and CTAT) to compensate for each other. By combining voltages with positive and negative temperature dependencies, the system achieves temperature-independent reference voltage output, resolving the contradiction between precision and temperature stability.
2Measurement precision
If complex circuits are used to generate reference voltage, then voltage precision can be improved, but circuit complexity increases
Solution Approach 1:
Multiple voltage generation functions (current generation, PTAT voltage generation, CTAT voltage generation) are merged into a single integrated circuit. This consolidation achieves precise reference voltage while avoiding the complexity of multiple separate circuits, as all components share common current sources and are tightly coupled.
Solution Approach 2:
The current generator serves multiple purposes: it provides bias current for the PTAT voltage generator, bias current for the CTAT voltage generator, and establishes the reference current level. This multi-functionality reduces the need for separate current sources, simplifying the overall circuit while maintaining precision.
3Device complexity
If standard voltage generation circuits are used, then device simplicity is maintained, but voltage constancy deteriorates across temperature ranges
Solution Approach 1:
The circuit converts the harmful effect of temperature changes into a beneficial compensation mechanism. By intentionally introducing PTAT and CTAT voltage generators with opposite temperature coefficients, the temperature variations that would normally degrade performance are instead used to compensate for each other, achieving voltage constancy while maintaining relatively simple circuit architecture.
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 circuit generates a reference voltage that remains constant within +/−10 ppm of the target voltage from −20 to 150 degrees Celsius, minimizing electromagnetic emissions and maintaining precise voltage conversion in electronic devices.
Implementation Method 1
The PTAT voltage generator is configured to receive the second current from the current generator, and generate a third voltage based on the second current
Implementation Method 2
The CTAT voltage generator is configured to receive the first current and the third current from the current generator, and generate a reference voltage based on the first current, the second current, and the third voltage
Implementation Method 3
The current generator is configured to generate a first current, and mirror the first current into a second current and a third current
Data Source
AI summary
A circuit may include a current generator coupled to a first voltage source. The current generator may be configured to generate a first current, and mirror the first current into a second current and a third current. The circuit may include a proportional to absolute temperature (“PTAT”) voltage generator coupled to the current generator and a second voltage source. The PTAT voltage generator may be configured to receive the second current from the current generator, and generate a third voltage based on the second current. The circuit may include a complementary to absolute temperature (“CTAT”) voltage generator coupled to the current generator and to the PTAT voltage generator. The CTAT voltage generator may be configured to receive the first current and the third current from the current generator, and generate a reference voltage based on the first current, the second current, and the third voltage.