AN4148 : Audible Noise Reduction Techniques for FPS Applications
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Các nguồn nhiễu nghe thấy được :
- Từ các chế tạo biến áp xung
- Từ mạch phản hồi.
In general, switched mode power supplies do not generate audible noise when they operate at constant ultrasonic frequencies (>20kHz). However, some switched mode power supplies can produce audible noise at certain load conditions. Most Fairchild Power Switches are designed to enter into burst switching operation at light load conditions to reduce standby consumption, which can cause audible noise when the fundamental frequency of the burst switching bundles is in the range of human hearing as shown in Figure1 (attachment).
This application note explains the major sources of audible noise and offers useful tips to engineers to solve the audible noise problem in their Fairchild Power Switch (FPS) applications.