News

Home  -  News  -  Industry News

Characteristics of Switching Power Adapter Transient Loads

source:Industry News Popular:adapter release time:2022-05-05 09:39:02 Article author:yu

  

Characteristics of Switching Power Adapter Transient Loads(图1)

  In the process of working and running, the switching power adapter has the advantages of reliable operation and easy portability, which is also closely related to its integrated system and miniaturized package selection. As a widely used power supply conversion device, the switching power adapter also has a load capacity for transient currents. Let's explore the actual characteristics of this transient load in detail.

  The transient load of the switching power adapter is also called di/dt dynamic load by engineers in daily work. This remarkable feature is that the load current often changes transiently, and the rate of change of the load current is very large. Taking an example to make a specific analysis, the current change rate of high-speed logic circuits and RF microwave transmitters may exceed 100A/ps during operation. The low-voltage microprocessors currently produced will also affect the switching power supply when rapidly switching between different operating modes, and the output current of the switching power supply can change by several orders of magnitude within a few nanoseconds.

  In addition to the examples listed above, many current computer switching power adapters can also handle transient load problems. The voltage of many notebook computers in our country is +3.3V, and the switching power supply is required to respond to the load current jump of 30A/us when the data is retrieved from the database. Assume that the time it takes for the load current to change from zero to 5A is 1us. If the bandwidth of the switching power supply is 25kHz, the time required to complete the above changes is 1/25 kHz=40us. Assuming that the current rises linearly, the amount of missing charge is (5A/2) X40us=100uC. If the +3.3 voltage fluctuation is allowed to fluctuate by 50mV, and the instantaneous energy is provided by the output filter capacitor, a capacitance of 100 uC/50mV=2000uF is required to prevent the voltage from falling below the specified value.

  However, when engineers take advantage of the transient load characteristics of switching power adapters for voltage processing, it is important to note that one can not expect to achieve the above-mentioned goals by using only one nominal capacitor. Engineers should choose to use several small-capacity capacitors in parallel to form 2200uF in combination with the actual situation, and then perform capacity calculation and transient current processing. Because the total output filter capacitor equivalent series resistance R’esr=50mV/5A=10mΩ, the equivalent series resistance of each small-capacity capacitor should be R’esr=10mΩ/n. When n=4, R'esr=40mΩ. This greatly reduces the requirements for output filter capacitors.


Read recommendations:

24W Chinese standard

48W desktop

36W Open Frame Power Supply

Can the power adapter be boarded?

Computer power adapter manufacturers.ac power adapter price

Previous:Key Components Selection Requirements for Class II and Class I Power Adapters Back to list Next:Reasons for Inrush Current in Switching Power Supply Design.adjustable power adapter

The latest article

Related Products

The latest article

2003-2004

2025-03-25

2004-2006

2025-03-25

2006-2008

2025-03-25

2009-2011

2025-03-25

2012-2014

2025-03-25

2014-2017

2025-03-25

2018-2022

2025-03-25

2022-2024

2025-03-25

2024-2025

2025-03-25

What are the types of mobile phone chargers and their functions?

2022-05-21

Advantages of switching power adapters

2022-05-21

Five core functions that the power adapter can achieve.adapter manufacture

2022-05-20

Analysis of the importance of power adapters for notebooks.adapter Processor

2022-05-20

Details of switching power supply in maintenance

2022-05-19

Understand the precautions of the power adapter and be an expert in electricity safety

2022-05-19

This is how the EMC interference of the switching power supply is generated.adapter wholesaler

2022-05-18

The relationship between the nominal voltage and current of the power adapter.power adapter price

2022-05-18

Five basic functions of notebook power adapters.adapter wholesaler

2022-05-17

Lightning surge immunity test method.power adapter price

2022-05-17

Switching power supply ripple source and control

2022-05-16

Level 6 energy efficiency standard power adapter T series

2022-05-16

Children sleeping with pacifiers are prone to tooth decay

2022-05-16

Six methods to deal with the heating problem of switching power supply transformer

2022-05-14

The principle of flyback switching power supply

2022-05-14

Types of thermal protection for power adapters.adjustable power adapter

2022-05-13

Summary of common faults of LED switching power supply

2022-05-13

The power transistor should be used like this in the power adapter

2022-05-12

4 modulation methods of switching power supply

2022-05-12

Some little knowledge about switching power supply

2022-05-11

Laptop Power Adapter Troubleshooting Steps

2022-05-11