Bandgap Reference Circuit With Feedback Boost for Stable Output
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Solution Overview
Problem
The existing bandgap reference circuits have limited output driving capability and gain, which restricts their performance and stability, especially when adjusting component parameters to achieve constant reference voltage or current.
Innovation Solution
The bandgap reference circuit design includes a feedback transistor connected to a power supply, a reference setting circuit with parallel bridge arms, and an amplification circuit, which provides greater current to the reference setting circuit, improving driving capability and stability by using PNP triodes for voltage adjustment and resistance sub-circuits with adjustable resistances, ensuring a zero temperature coefficient voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If component parameters are adjusted to achieve constant reference voltage or current, then the reference stability is improved, but the output driving capability is limited
Solution Approach 1:
The circuit is divided into multiple functional modules: reference voltage generation module, amplification module, and output module. Each module performs a specific function, allowing the reference stability to be optimized independently while the output driving capability is enhanced through the dedicated output transistor M2 and feedback transistor M1 configuration.
Solution Approach 2:
A feedback mechanism is implemented where the output terminal connects to the gate of feedback transistor M1, which in turn connects to the reference setting circuit. This feedback loop continuously adjusts the output to maintain constant reference voltage or current while providing sufficient driving capability through the feedback transistor's current control.
2Reliability
If component parameters are adjusted to achieve constant reference voltage or current, then the reference stability is improved, but the gain is insufficient
Solution Approach 1:
An amplification circuit is introduced as an intermediary between the reference setting circuit and the output transistor. This amplification stage boosts the signal gain while the feedback transistor M1 ensures stability by continuously regulating the output based on the amplified signal, thus resolving the contradiction between gain and stability.
3Power
If PNP triodes are used for voltage adjustment, then the current driving capability is improved, but the circuit complexity increases
Solution Approach 1:
The PNP triodes (M1 and M2) are designed to perform multiple functions: M1 acts as both a feedback element for stability and a current amplification device for driving capability, while M2 serves as both an output transistor and a current regulation element. This multi-functionality reduces the need for additional components, thereby limiting the increase in circuit complexity.
Data Source
AI summary
A bandgap reference circuit includes a feedback transistor, a reference setting circuit, an amplification circuit and an output transistor. A source of the feedback transistor is configured to connect to a first power supply, and a drain of the feedback transistor is configured to connect to a first node. The reference setting circuit includes a first bridge arm and a second bridge arm which are connected in parallel. An inverting input terminal of the amplification circuit is connected to the first bridge arm, and a non-inverting input terminal of the amplification circuit is connected to the second bridge arm. A gate of the output transistor is connected to an output terminal of the amplification circuit, and a source of the output transistor is connected to the first power supply.