Switching Power Supply Intermittent Oscillation Noise Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Switching power supply devices face challenges in reducing audible noise due to load fluctuations during intermittent oscillation control, leading to unstable control and increased circuit complexity, especially during light loads.
Innovation Solution
A switching power supply device with an intermittent oscillation control circuit that adjusts the oscillation time period by comparing it with a target period, extending or shortening it by a predetermined time, and using a comparator to set the oscillation time period based on feedback signals, thereby stabilizing control without adding complex stabilization circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If intermittent oscillation control is used to improve power supply efficiency during light load, then power supply efficiency is improved, but audible noise is generated due to low oscillation frequency
Solution Approach 1:
The patent changes the oscillation frequency parameter from audible range to ultrasonic range (above 20 kHz) by adjusting the oscillation period. This allows the system to maintain intermittent oscillation control for light load efficiency while moving the noise frequency beyond human hearing range, thus resolving the contradiction between efficiency improvement and noise generation.
2Object-generated harmful factors
If the intermittent oscillation period is adjusted to suppress audible noise, then audible noise is reduced, but control becomes unstable during load fluctuation
Solution Approach 1:
The patent implements a feedback mechanism where the oscillation period is dynamically adjusted based on detected load conditions. The system monitors load changes and automatically stabilizes the oscillation period to maintain control stability while suppressing audible noise, preventing the instability that occurs with fixed period adjustment.
Solution Approach 2:
The patent makes the oscillation period dynamic rather than fixed, allowing it to adapt to changing load conditions. This dynamic adjustment ensures that the control remains stable during load fluctuations while maintaining noise suppression, resolving the contradiction between noise reduction and control stability.
3Reliability
If a filter circuit is added to stabilize control during intermittent oscillation, then control stability is improved, but circuit complexity increases
Solution Approach 1:
The patent enables the control circuit to self-stabilize by using feedback from the oscillation detection itself. The system uses the existing oscillation signals to automatically adjust and stabilize the period without requiring external filter circuits, achieving control stability while avoiding increased circuit complexity.
Data Source
AI summary
A switching power supply circuit includes an intermittent oscillation control circuit, which performs intermittent oscillation control that repeats a cycle including an oscillation time period and a stop time period according to a feedback signal so that output voltage or current becomes constant, compares an intermittent oscillation period that is a sum of the oscillation time period and the stop time period with a preset target period, sets the oscillation time period of current cycle to a length obtained by extending the oscillation time period of previous cycle by first predetermined time when the intermittent oscillation period is shorter than the target period, and sets the oscillation time period of current cycle to a length obtained by subtracting second predetermined time from the oscillation time period of previous cycle when the intermittent oscillation period is longer than the target period, in each cycle of intermittent oscillation control.