Bandgap Reference Module for Fast-Start Low-Noise Linear Regulators
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Solution Overview
Problem
Portable electronic devices, such as IoT devices, require a linear regulator that consumes low power, has low noise, and achieves fast start-up times to extend battery life and ensure proper functionality, as existing solutions often fail to meet these criteria effectively.
Innovation Solution
A bandgap module comprising a bandgap circuit, a start-up module, and a lowpass filter, which includes an operational amplifier, current mirror, loading branches, and bandgap branches, along with a coarse and fine start-up circuit to rapidly generate and maintain a stable reference voltage, reducing power consumption and noise while accelerating start-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional linear regulator is used to provide stable regulated voltage, then voltage stability is improved, but quiescent current consumption increases
Solution Approach 1:
The patent implements dynamic current control by switching between coarse and fine start-up circuits based on operational phase. The bandgap circuit dynamically adjusts its current consumption: during coarse start-up, higher current is used for rapid voltage establishment; during fine start-up and steady state, lower current maintains precision. This dynamic adaptation resolves the contradiction between stability and energy consumption.
Solution Approach 2:
The start-up process is segmented into two distinct phases: coarse start-up and fine start-up. The coarse start-up circuit uses higher current for rapid voltage generation, while the fine start-up circuit uses lower current for precision adjustment. This segmentation allows the system to optimize current consumption at different operational stages, achieving both fast start-up and low quiescent current.
2Stability of the object's composition
If a conventional linear regulator is used to provide stable regulated voltage, then voltage stability is improved, but start-up time increases
Solution Approach 1:
The start-up process is divided into two segments: coarse start-up for rapid voltage establishment and fine start-up for precision adjustment. The coarse start-up circuit quickly generates the reference voltage, significantly reducing start-up time, while the fine start-up circuit subsequently refines the voltage for stability. This segmented approach resolves the contradiction between fast start-up and voltage stability.
Solution Approach 2:
The coarse start-up circuit performs preliminary action by rapidly establishing the reference voltage before the fine start-up circuit takes over for precision adjustment. This preliminary high-current phase jump-starts the voltage generation, reducing overall start-up time while the subsequent fine-tuning ensures stability.
3Measurement precision
If a conventional linear regulator is used to provide stable regulated voltage, then precision is improved, but noise increases
Solution Approach 1:
The patent implements dynamic current adjustment where the bandgap circuit operates at higher current during coarse start-up for rapid voltage establishment, then transitions to lower current during fine start-up and steady state. This reduces noise generation while maintaining precision, as lower current operation produces less thermal noise during the phases where extreme precision is less critical.
Solution Approach 2:
The patent changes the operating current parameter dynamically based on operational phase. During coarse start-up, higher current is used; during fine start-up and steady state, lower current maintains precision with reduced noise. This parameter change resolves the contradiction between precision and noise by optimizing current at different stages.
Data Source
AI summary
A bandgap module and a linear regulator are provided. The linear regulator includes the bandgap module and an error amplifier. The voltage supply voltage includes a bandgap circuit, a lowpass filter, and a start-up module. The voltage supply voltage generates a bandgap voltage. The lowpass filter filters the bandgap voltage and generates a reference voltage accordingly. The start-up module includes a first start-up circuit and a second start-up circuit. The bandgap voltage is increased to a predefined value when the bandgap module operates in a first phase. The bandgap voltage maintains at the predefined value when the bandgap module operates in a second phase. The second phase is after the first phase.