Bias Circuit Second Current Path Bandgap Reference Stabilization
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Solution Overview
Problem
Existing bias circuits with bandgap references become unstable due to power supply fluctuations, particularly as the power supply voltage increases, leading to prolonged instability and delayed stabilization.
Innovation Solution
A bias circuit design incorporating a first current path for driving the bandgap reference and a second current path that supplies current for a predetermined period after power-on, utilizing a capacitor and resistor configuration to manage current flow and maintain constant voltage operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single current path is used to supply current to the bandgap reference, then the circuit structure is simple, but the circuit becomes unstable when power supply voltage increases and stabilization time is prolonged
Solution Approach 1:
The current supply function is segmented into two distinct current paths: a first current path that supplies current during normal operation, and a second current path that supplies current during the power-on period. This segmentation allows each path to be optimized for its specific function, with the second path dedicated to rapid initial stabilization without affecting the normal operation path.
Solution Approach 2:
The second current path is activated preliminarily during the power-on period to establish stable operation of the bandgap reference before normal operation begins. By providing dedicated current supply during this critical initialization phase, the circuit achieves rapid stabilization and prevents the instability that would otherwise occur when power supply voltage increases during startup.
2Power
If the power supply voltage increases during operation, then the available power increases, but the bandgap reference becomes unstable and current fluctuation occurs
Solution Approach 1:
The constant voltage generation circuit generates a constant voltage that is fed back to the second current path. This feedback mechanism maintains a constant voltage at the current supply point for the bandgap reference even when power supply voltage increases, thereby preventing current fluctuation and maintaining stable operation throughout the power-on period and beyond.
3Loss of time
If the circuit is designed for rapid stabilization, then the stabilization time is shortened, but the circuit structure becomes more complex
Solution Approach 1:
The current supply function is segmented into two distinct current paths: a first current path that supplies current during normal operation, and a second current path that supplies current during the power-on period. This segmentation allows each path to be optimized for its specific function, with the second path dedicated to rapid initial stabilization.
Solution Approach 2:
The second current path is designed with multi-functionality: it supplies current during the power-on period for rapid stabilization, and after the power-on period ends, it transitions to supplying current based on the constant voltage from the constant voltage generation circuit. This allows the same path structure to serve different functions at different times, achieving rapid stabilization without excessive complexity.
Data Source
AI summary
In a conventional bias circuit, as a power supply voltage increases, a current supplied to a bandgap reference becomes unstable due to a fluctuation of the power supply voltage, which makes it impossible for the bias circuit to perform stable bias operations in some cases. A bias circuit of the present invention has a bandgap reference, and includes a first current path supplying a drive current to the bandgap reference, and a second current path supplying a current to the bandgap reference for a predetermined period of time after power-on.