Bandgap Voltage Generator Stability via Start-Up Circuit Bias Adjustment
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Solution Overview
Problem
Conventional bandgap voltage generators face instability and inaccuracies due to low voltage values at the positive and negative input ends of the operational amplifier, leading to ineffective bias voltage generation.
Innovation Solution
A voltage generating circuit that incorporates a start-up circuit with a comparison circuit and a voltage regulator to adjust the bias voltage output of the operational amplifier, enhancing the stability and accuracy of the bandgap voltage generator by increasing the voltage values at the input ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voltage values at the positive and negative input ends of the operational amplifier are too low in the conventional bandgap voltage generator, then the differential input circuit is shut and the operational amplifier fails to provide effective bias voltage, but increasing the voltage values requires additional circuit complexity
Solution Approach 1:
The patent applies preliminary action by using a start-up circuit to pre-establish appropriate voltage levels at the operational amplifier input ends before the main bandgap voltage generation begins. The start-up circuit activates first to ensure the differential input circuit is properly biased, preventing shutdown and ensuring stable operation throughout the bandgap voltage generation process.
Solution Approach 2:
The patent uses an intermediary approach by introducing a voltage regulator as a mediating component between the operational amplifier and the bandgap voltage generator. This voltage regulator adjusts and maintains appropriate voltage levels at the input ends, acting as an intermediary that ensures stable operation without requiring complete redesign of the core bandgap circuitry.
2Quantity of substance
If the bias voltage output by the operational amplifier is not adjusted, then the bandgap current value is reduced, but adjusting the bias voltage requires additional voltage regulator components
Solution Approach 1:
The voltage regulator in the patent is designed with multi-functionality, serving both to adjust the bias voltage output by the operational amplifier and to regulate the bandgap current. This single component performs multiple functions, increasing the bandgap current value while minimizing the addition of separate dedicated current regulation components.
Solution Approach 2:
The patent applies parameter changes by using the voltage regulator to dynamically adjust the bias voltage parameter, which in turn modifies the bandgap current parameter. By changing the voltage parameter through the regulator, the current parameter is indirectly controlled and enhanced without requiring direct current regulation circuitry.
Data Source
AI summary
In a voltage generating circuit, a bandgap voltage generator has a first operational amplifier to receive a first voltage and a second voltage, and generate a bias voltage by comparing the first voltage and the second voltage, wherein the bandgap voltage generator generates a bandgap current according to the bias voltage and generates an output voltage according to the bandgap current. In a start-up circuit, a comparison circuit compares the first voltage or the second voltage with a reference voltage to generate a first comparison result, and generates a first current according to the first comparison result. A voltage regulator generates a second current according to the first current, and compares the second current with a reference current to generate a second comparison result, and adjusts a voltage value of the bias voltage according to the second comparison result.