Bandgap Reference Start-Up Circuit for Stable PVT Operation
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Solution Overview
Problem
Existing bandgap reference voltage generation circuits fail to stably generate reference voltages during initial start-up operations due to changes in driving environments such as supply voltage, process, and temperature, leading to abnormal voltage outputs.
Innovation Solution
A bandgap reference voltage generation circuit incorporating a start-up circuit with a beta-multiplier reference circuit and a comparator to ensure stable start-up and operation, using a Schmitt trigger circuit to mitigate power noise, and terminating the start-up circuit when the reference voltage reaches a target value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bandgap reference voltage generation circuit is used, then the circuit structure is simple, but the circuit fails to stably generate reference voltage during initial start-up operation due to changes in driving environment
Solution Approach 1:
The start-up circuit is activated before the main bandgap reference circuit to pre-charge capacitors and establish initial operating conditions. This preliminary action ensures that when the main circuit activates, all nodes are already at appropriate voltage levels, preventing start-up failures regardless of supply voltage rise time or temperature conditions.
Solution Approach 2:
The start-up circuit acts as an intermediary between the power supply and the main bandgap reference circuit. It provides a controlled activation sequence and ensures proper biasing conditions are established before the main circuit begins operation, isolating the main circuit from variations in power supply characteristics.
2Reliability
If the start-up circuit operates continuously to ensure stable start-up, then start-up reliability is improved, but power consumption increases
Solution Approach 1:
The start-up circuit operates periodically rather than continuously. It activates when detection circuits sense that the bandgap reference voltage is below a threshold level, and deactivates when the voltage stabilizes above the threshold. This periodic operation maintains reliability while minimizing unnecessary power consumption during normal operation.
Solution Approach 2:
Detection circuits continuously monitor the bandgap reference voltage and provide feedback to control the start-up circuit's operation. When the reference voltage reaches the target level, the feedback signal automatically turns off the start-up circuit, eliminating power consumption. This feedback mechanism ensures the circuit only consumes additional power when actually needed.
Data Source
AI summary
A bandgap reference voltage generation circuit, capable of stably generating a bandgap reference voltage by implementing a stable start-up operation regardless of changes in a driving environment, comprising: a start-up circuit that outputs a start-up signal when a first power voltage rises; and a bandgap reference core circuit in which an operation is enabled in response to the start-up signal and that generates and outputs the bandgap reference voltage, wherein the start-up circuit may include: a beta-multiplier reference circuit including a cascode current mirror circuit that forms a first current path and a second current path between a first power line and a second power line; a start-up output unit that outputs the start-up signal in response to a voltage of an output node of the second current path; and a comparator that compares the bandgap reference voltage with a target voltage to disable the operation of the start-up circuit.