Closed-Loop Voltage Reference Circuit for Temperature and Load Stability
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Solution Overview
Problem
Existing bandgap voltage reference circuits are affected by temperature variation and load current changes, leading to fluctuations in output voltage and inability to maintain a stable temperature coefficient.
Innovation Solution
A voltage supply circuit with a closed-loop control architecture using variable resistors in two loops to adjust the temperature coefficient slope and maintain a zero temperature coefficient, while also preventing output voltage fluctuations due to load current changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transistors are fabricated by different processes or parameters vary due to process drift, then the reference voltage is affected by temperature variation, but using identical transistors and processes limits manufacturing flexibility and adaptability
Solution Approach 1:
The patent employs a bandgap voltage reference circuit that uses feedback mechanisms to compensate for temperature variations. The circuit monitors temperature changes and adjusts the reference voltage accordingly, ensuring stable output despite process variations or temperature fluctuations. This feedback approach resolves the contradiction by maintaining reliability through active compensation rather than relying solely on identical transistor fabrication.
2Reliability
If the load current of the bandgap voltage reference circuit increases, then the DC voltage level decreases and the temperature coefficient diminishes, but reducing load current limits the circuit's power delivery capability
Solution Approach 1:
The patent implements dynamic adjustment mechanisms within the bandgap voltage reference circuit that adapt to varying load current conditions. The circuit dynamically compensates for the decrease in DC voltage level and maintains the temperature coefficient across different load currents. This dynamic approach allows the circuit to maintain reliability under varying power demands without being constrained to a fixed operating point.
3Reliability
If conventional bandgap voltage reference circuits are used, then the output voltage is affected by both temperature variation and load current changes, but adding complex compensation circuits increases device complexity
Solution Approach 1:
The patent merges the temperature compensation and load regulation functions into the core bandgap voltage reference circuit architecture. By integrating these compensation mechanisms directly into the reference circuit rather than adding separate external circuits, the patent achieves improved output voltage stability against both temperature and load variations while minimizing the increase in overall device complexity. The compensation elements are seamlessly incorporated into the existing circuit topology.
Data Source
AI summary
A voltage supply circuit includes a first loop and a second loop. The first loop includes a first and second transistor, and a first and second resistor. The first resistor couples to the first transistor. The second resistor couples between the first and second transistor. The second loop includes a third and fourth transistor, and a third and fourth resistor. The third resistor and the third transistor couple at an output node for providing an output voltage. The fourth resistor couples between the third resistor and the fourth transistor. The first and third transistor couple to a high-voltage level terminal. A control terminal of the first transistor couples to that of the third transistor. The second and fourth transistor couples to a low-voltage level terminal. A control terminal of the second transistor couples to that of the fourth transistor. The first resistor to the fourth resistor include variable resistors.