Bandgap Reference Voltage Circuit Insensitive to Element Mismatch
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Solution Overview
Problem
Integrated circuits face challenges in maintaining stable reference voltages due to element mismatch induced by process variations, which affects the reliability of bandgap reference circuits under PVT variations.
Innovation Solution
A reference voltage generation circuit comprising a bandgap reference circuit and a voltage adjustment circuit, where the voltage adjustment circuit compares the output voltage with the reference voltage and adjusts it to maintain stability, compensating for element mismatch through a comparator and path control circuit, ensuring the output voltage remains constant despite temperature and process variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a bandgap reference circuit is used to generate a reference voltage, then the reference voltage remains stable under temperature variations, but the reference voltage may vary due to mismatch between elements induced by process variations
Solution Approach 1:
The patent employs a feedback mechanism where the output voltage is fed back to the non-inverting input terminal of an operational amplifier, while the reference voltage is applied to the inverting input terminal. The operational amplifier adjusts the output voltage based on the voltage difference detected at its inputs, creating a closed-loop feedback system that automatically compensates for element mismatch and maintains output voltage stability despite process variations
Solution Approach 2:
The operational amplifier serves as an intermediary device that mediates between the reference voltage and the output voltage. It detects the voltage difference between the reference voltage (applied to inverting input) and the feedback voltage (applied to non-inverting input), and generates appropriate control signals to adjust the output voltage, thereby eliminating the direct impact of element mismatch on the reference voltage
2Reliability
If a voltage adjustment circuit is added to compensate for element mismatch, then the output voltage stability is improved, but the device complexity increases
Solution Approach 1:
The operational amplifier performs multiple functions within a single component: it acts as a voltage comparator to detect the difference between reference and feedback voltages, serves as a control element to adjust the output voltage, and provides high-impedance buffering. This multi-functionality allows the circuit to achieve precise voltage regulation without adding multiple separate control components, thereby limiting the increase in device complexity
Solution Approach 2:
The patent combines the reference voltage generation function and the voltage adjustment function into a single integrated circuit structure. The bandgap reference circuit and the operational amplifier-based voltage adjustment circuit are merged, where the operational amplifier directly controls the output node of the bandgap reference circuit, eliminating the need for separate adjustment stages and reducing overall circuit complexity
Data Source
AI summary
A reference voltage generation circuit for generating an output voltage is provided. The reference voltage generation circuit includes a bandgap reference circuit and a voltage adjustment circuit. The bandgap reference circuit generates the output voltage at an output node and a reference voltage. The voltage adjustment circuit is coupled to the bandgap reference circuit. The voltage adjustment circuit receives the output voltage and the reference voltage, compares the output voltage with the reference voltage to generate a comparison result, and adjusts the output voltage according to the comparison result.