home > News > Industry News

Six situations and solutions that cause the whistling of switching power supplies.power supply price

source:Industry News     Popular:adapter     release time:2022-05-18 10:07:11     Article author:yu    

  Six situations and solutions that cause the whistling of switching power supplies.power supply price(图1)

  The switching power supply controls the time ratio of the switching tube on and off in the circuit, and maintains a stable circuit voltage output. It is a very common power supply design. But those who have been engaged in the design of switching power supply know that in the process of testing the switching power supply, some whistling sounds are often heard, similar to the leakage sound when the high voltage is bad, or the sound like the high voltage arcing. So when these phenomena occur, how should they be addressed?

  Generally speaking, the reasons for the whistling of switching power supply generally have the following incentives.

  Poor dipping of transformer

  Includes unimpregnated varnish water. The whistling causes the waveform to have spikes, but the load capacity is generally normal. Special instructions: the higher the output power, the stronger the whistling, and the less powerful the performance is not necessarily obvious. A 72W charger product has had bad loading experience, and found in this product that there are strict requirements on the material of the magnetic core. In addition, when the design of the transformer is not good, it is also possible that the vibration will produce abnormal noise during operation.

  PWM IC ground trace error

  Usually, some products can work normally, but some products cannot be loaded and may not be able to vibrate. Especially when some low-power ICs are used, they are more likely to fail to work normally. For example, the SG6848 test board, because the performance of the IC was not thoroughly understood at the beginning, the layout was hastily based on experience, and the result was that the wide voltage test could not be performed during the test.

  Optocoupler working current point wiring error

  When the position of the working current resistor of the optocoupler is connected before the secondary filter capacitor, there is also the possibility of howling, especially when the load is more.

  Ground Wire Error of Reference Voltage Regulator IC TL431

  The grounding of the same secondary reference voltage regulator IC has the same requirements as the grounding of the primary IC, that is, they cannot be directly connected to the cold ground and hot ground of the transformer. If they are connected together, the result is that the load capacity is reduced and the howling sound is proportional to the output power.

  When the output load is large, close to the power limit of the power supply, the switching transformer may enter an unstable state. The duty cycle of the switch tube in the previous cycle was too large, the conduction time was too long, and too much energy was transmitted through the high-frequency transformer; the energy of the energy storage inductor of DC rectification was not fully released in this cycle, and it was judged by PWM that in the next cycle There is no drive signal to turn on the switch, or the duty cycle is too small. The switch tube is in the off state in the entire cycle thereafter, or the on time is too short. After the energy release of the energy storage inductor for more than one whole cycle, the output voltage drops, and the duty cycle of the switch tube in the next cycle will be larger... This cycle will cause the transformer to generate a lower frequency (regular intermittent full cut-off). period, or the frequency with which the duty cycle changes drastically), producing lower-frequency sounds that can be heard by the human ear.

  At the same time, the output voltage fluctuation will be larger than normal operation. When the number of intermittent full cut-off cycles per unit time reaches a considerable proportion of the total number of cycles, it will even reduce the vibration frequency of the transformer originally working in the ultrasonic frequency band, enter the audible frequency range, and emit sharp high frequencies. whistle". At this time, the switching transformer is working in a serious overload state, and there is a possibility of burning it at all times - this is the origin of the "screaming" before many power supplies burn out. I believe that some users have had similar experiences.


Read recommendations:

12-36W POE POWER SUPPLY

MKA-571652420 ADAPTER AC ADAPTER CE ADAPTOR UL ADAPTOR Linear Adapter

MK-C1806028 MKA ADAPTER LINEAR ADAPTOR SWITCHING ADAPTOR Linear Power Adapter Linear Adapter

How to deal with the electromagnetic interference of switching power supply which is difficult in EM

Judge the pros and cons of the power cord from the appearance

Related Information

What are the conditions of use and maintenance methods for switching power supplies?

2022-05-21

Some Frequently Asked Questions about Power Adapters

2022-05-20

How to deal with the electromagnetic interference of switching power supply which is difficult in EM

2022-05-19

Six situations and solutions that cause the whistling of switching power supplies.power supply price

2022-05-18

Lightning Surge Test Method for Switching Power Adapters.adapter factory

2022-05-17

Two common power adapter output overload protection methods.ADAPTOR price

2022-05-16

Common fault maintenance skills of switching power supply

2022-05-14

How should we choose the charger?

2022-05-13

Power adapter expertise.CE ADAPTOR

2022-05-12

How to solve the high temperature rise of switching power supply transformer?

2022-05-11

The role of varistor in switching power supply

2022-05-10

Structural characteristics and working principle of varistor

2022-05-09

The role of varistor in switching power supply

2022-05-09

What are the main components of switching power supply

2022-05-07

Two ways for MOS devices to dissipate in high-power power supplies,CE ADAPTOR Processing

2022-05-06

Several common insulation protection technologies for power adapters

2022-05-05

What are the unique advantages of high frequency switching power adapter

2022-04-27

What are the main components of switching power supply.China cnc plastic cutting

2022-04-26

Troubleshooting method of switching power supply,CE ADAPTOR wholesale

2022-04-25

How to use the power adapter correctly

2022-04-23

What is the comparison between a charger and an adapter?

2022-04-23

The optimal solution of drone power management solution!

2022-04-22

Several common insulation protection technologies for power adapters

2022-04-21

What are the unique advantages of high frequency switching power adapter

2022-04-20

General Mechanism Analysis of Switching Power Adapter.ac power adapter wholesaler

2022-04-19

Suppression method of low frequency ripple of switching power supply

2022-04-16

Why is the power adapter making noise?

2022-04-15

When the power adapter is in normal use, what is the normal temperature?

2022-04-14

90% of people use the car charger incorrectly, are you using it right?CAR POWER SUPPLY sales

2022-04-13

The difference between a power adapter and a voltage regulator

2022-04-12

Popular recommended products

QC3.0 24W USB Charger,24W USB Charger,24W USB Charger,USB Charger

2020-08-27

EI-35 ADAPTER AC ADAPTER SWITCHING ADAPTOR Linear Power Adapter Linear Adapter

2020-08-28

24W USB Charger,24W Charger,USB Charger

2020-08-27

MKD-571202000 ADAPTER AC ADAPTER CE ADAPTOR UL ADAPTOR Linear Adapter

2020-08-28

MKS-120200EU-36 Switching Power Supply

2020-08-29

MKS-1201250HEU Switching Power Supply

2020-08-29

36-90W Charger,36W Charger,90W Charger,40W Charger,50W Charger

2020-08-27

3-12W Medical Switching Power Supply 3W Switching Power Supply 12W Power Supply

2020-08-27

12W POWER SUPPLY,12W CAR POWER SUPPLY,POWER SUPPLY,CAR POWER SUPPLY

2020-08-27

500W Charger,Charger

2020-08-28

MKS-1202000-36 Switching Power Supply

2020-08-29

12W 2USB Charger,2USB Charger,12W Charger,USB Charger

2020-08-27

30W PD Charger,30W Charger,PD Charger

2020-08-27

100-300W Charger,100W Charger,200W Charger,300W Charger

2020-08-27

30-500W LED Power Supply 30-500W Power Supply

2020-08-27

200-500W Switching Power Supply

2020-08-29

3-100W PCBA power supply 3-100W Customized power supply 3-100W power supply

2020-08-27

Transformer,Power Transformer,Ring Power Transformer

2020-08-27

24W 2USB Charger,24W Charger ,2USB Charger

2020-08-27

12-24W Medical Switching Power Supply

2020-08-27

EI-66 ADAPTER LINEAR ADAPTOR SWITCHING ADAPTOR Linear Power Adapter Linear Adapter

2020-08-28

24V1.5A 36W Switching Power Supply

2020-08-29

MKA-571652420 ADAPTER AC ADAPTER CE ADAPTOR UL ADAPTOR Linear Adapter

2020-08-28

EI-57 ADAPTER LINEAR ADAPTOR Linear Power Adapter Switching Power Adapter INTERCHANGEABLE ADAPTOR Li

2020-08-28

12VDC8A 96W power supply

2020-08-28

12-36W POE POWER SUPPLY

2020-08-27

12V2ASwitching Power Supply

2020-08-28

36-65W Switching Power Supply

2020-08-29

24V21A LED Power Supply 24V Power Supply 21A Power Supply

2020-08-27

72-200W Switching Power Supply

2020-08-29
Copyright 2020 © Merryking Technology Co., Ltd. All rights reserved