Buffered Bipolar Reference Voltage Circuit for Low-Noise Temperature Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional reference voltage circuits using bipolar transistors face challenges in reducing the number of transistors and minimizing noise interference, while maintaining temperature stability and precision.
Innovation Solution
A reference voltage circuit design incorporating two current sources, bipolar transistors, resistors, and operational and buffer amplifiers, where the area ratio and resistance values of the bipolar transistors and resistors are adjusted to suppress temperature dependence and noise interference, utilizing a buffer amplifier to stabilize the output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of bipolar transistors is reduced, then manufacturing cost and device complexity are improved, but temperature stability and precision deteriorate
Solution Approach 1:
The patent merges multiple functions into fewer transistors. Specifically, the first and second transistors are configured to simultaneously generate reference voltages and provide temperature compensation through their interconnected arrangement, eliminating the need for separate compensation circuits and reducing the total transistor count while maintaining temperature stability.
Solution Approach 2:
Each transistor in the circuit is designed to perform multiple functions. The first transistor generates a reference voltage while also contributing to temperature compensation. The second transistor similarly provides both reference voltage generation and temperature stabilization, making each component multi-functional to reduce overall device complexity.
2Measurement precision
If noise suppression measures are added, then output precision is improved, but device complexity increases
Solution Approach 1:
The patent converts the inherent temperature-dependent variations, which could be considered harmful noise, into a beneficial temperature compensation mechanism. By designing the circuit so that the voltage changes in one transistor path counterbalance the changes in another path, the temperature variations are transformed into a self-correcting feature that improves output precision without requiring external noise suppression circuitry.
3Stability of the object's composition
If temperature compensation is enhanced, then reference voltage stability is improved, but the number of components increases
Solution Approach 1:
The temperature compensation function is segmented and distributed across the existing transistor pairs rather than concentrated in a separate compensation circuit. Each transistor pair (first and second transistors, third and fourth transistors) independently contributes to temperature compensation, allowing the stability function to be embedded within the existing structure without adding extra components.
Data Source
AI summary
The present invention includes: a first current source, through which a first current is made to flow; a second current source, through which a second current set at a certain ratio to the first current is made to flow; a first current path, which includes a second resistor, a first resistor, and a first bipolar transistor that are connected to the first current source in a sequential manner, and through which the first current is made to flow; a second current path, which includes a third resistor and a 0th bipolar transistor that are connected to the second current source in a sequential manner, and through which the second current is made to flow; an operational amplifier, which controls current amounts of the first current and the second current by an output from an output end, and of which a positive input end is connected to a connection point between the second resistor and the first resistor, and of which a negative input end is connected to a connection point between the third resistor and the 0th bipolar transistor; and a buffer amplifier, which outputs a reference voltage, and of which a positive input end is connected to a connection point between the second current source and the third resistor, and of which a negative input end is connected to an output end; wherein an area ratio of the first bipolar transistor to the 0th bipolar transistor is n:1, and a reference voltage of which temperature dependence is corrected is obtained by adjusting resistance values of the first and the third resistor and a value of the area ratio n.