Linear Regulator Bypass Mode for Switching Noise Reduction
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Solution Overview
Problem
Switching power supplies generate noise that can hinder voltage regulation, impacting reference voltage sources and affecting the stability of output voltage in electronic devices.
Innovation Solution
A power supply apparatus incorporating a switching power supply, a reference voltage source, and a linear regulator that operates in bypass mode during startup and transitions to regulation mode once the reference voltage exceeds a predetermined value, using a switch circuit to stabilize the input voltage and reduce noise impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a switching power supply is used to step up or step down voltage, then voltage conversion efficiency is improved, but switching noise is generated that can hinder voltage regulation
Solution Approach 1:
A linear regulator is introduced as an intermediary component between the switching power supply and the reference voltage source. The linear regulator filters out switching noise from the input voltage before it reaches the reference voltage source, while the switching power supply continues to provide efficient voltage conversion. This mediator approach allows the system to maintain both high efficiency and low noise performance.
2Device complexity
If the reference voltage source is powered directly from the switching power supply output, then device complexity is reduced, but noise from the switching element impacts the reference voltage stability
Solution Approach 1:
The linear regulator serves as a mediator between the switching power supply and the reference voltage source. It provides electrical isolation and noise filtering, ensuring that the reference voltage source receives a clean power supply while the overall system remains relatively simple in structure.
3Stability of the object's composition
If the linear regulator operates in regulation mode from startup, then voltage stability is improved, but startup time increases due to reference voltage establishment delay
Solution Approach 1:
The linear regulator dynamically switches between bypass mode and regulation mode during startup. Initially, it operates in bypass mode to provide immediate voltage output for fast startup. Once the reference voltage is established, it transitions to regulation mode to provide stable voltage. This dynamic operation optimizes both startup time and voltage stability.
Solution Approach 2:
The system performs preliminary action by establishing the reference voltage through the linear regulator in regulation mode before switching to bypass mode for normal operation. This ensures that the reference voltage is ready and stable before the main voltage regulation begins, preventing startup issues.
Data Source
AI summary
A linear regulator is provided which stabilizes an input voltage based on a reference voltage source that generates a reference voltage, and the reference voltage generated by the reference voltage. An output voltage of the linear regulator is supplied as a power supply voltage of a switching controller and the reference voltage source. The linear regulator is configured to enable switching of a regulation mode in which voltage is outputted according to the reference voltage, and a bypass mode in which an input voltage is outputted as it is, with no relation to the reference voltage. When a power supply apparatus is started up, during a time period until the input voltage reaches a predetermined threshold voltage, the linear regulator operates in the bypass mode, and when the input voltage exceeds the threshold voltage, operates in the regulation mode.