home > News > Industry News

What are the advantages and disadvantages of the 5 classic switching power supply structures?

source:Industry News     Popular:adapter     release time:2021-09-11 09:26:49     Article author:sznbone    

  What are the advantages and disadvantages of the 5 classic switching power supply structures?

  1. Single-ended forward

  Single-ended: The pulse transformer is unidirectionally driven by a switching device.

  Forward: The primary/secondary phase relationship of the pulse transformer ensures that when the switch tube is turned on and the primary side of the pulse transformer is driven, the secondary side of the transformer simultaneously supplies power to the load.

  The biggest problem of this circuit is that the switch tube T works alternately in on/off states. When the switch tube is turned off, the pulse transformer is in a "no-load" state, and the stored magnetic energy will be accumulated in the next cycle until the inductance The device saturates, causing the switching device to burn out. The magnetic flux reset circuit composed of D3 and N3 in the figure provides a channel for venting excess magnetic energy.

What are the advantages and disadvantages of the 5 classic switching power supply structures?(图1)

  2, single-ended flyback

  The flyback circuit is opposite to the forward circuit. The primary/secondary phase relationship of the pulse transformer ensures that when the switch tube is turned on and the primary side of the pulse transformer is driven, the secondary side of the transformer does not supply power to the load, that is, the primary/secondary side is switched on and off alternately . The problem of the accumulation of magnetic energy of the pulse transformer is easy to solve. However, due to the leakage inductance of the transformer, a voltage spike will be formed on the primary side, which may break down the switching device. A voltage clamp circuit is required to protect the circuit composed of D3 and N3. From the circuit schematic diagram, the flyback and the forward are very similar. On the surface, it is only the difference between the same name end of the transformer, but the working mode of the circuit is different, and the functions of D3 and N3 are also different.

  3, push-pull (transformer center tap) type

  The characteristics of this circuit structure are: symmetrical structure, the primary side of the pulse transformer is two symmetrical coils, the two switch tubes are connected in a symmetrical relationship, and the circulation is broken. The working process is similar to the class B push-pull power amplifier in the linear amplifier circuit.

  Main advantages: high utilization rate of high-frequency transformer core (compared with single-ended circuit), high utilization rate of power supply voltage (compared with half-bridge circuit to be described later), high output power, low power for both tube bases Flat and simple driving circuit.

  The main disadvantages: low utilization of transformer windings and relatively high requirements for the withstand voltage of the switching tube (at least twice the power supply voltage).

  4, full bridge

  The characteristic of this circuit structure is that four identical switch tubes are connected into a bridge structure to drive the primary side of the pulse transformer.

  In the figure, T1 and T4 are a pair, which are driven by the same set of signals and turn on/off at the same time; T2 and T3 are another pair, which are driven by another set of signals and turn on and off at the same time. The two pairs of switching tube wheels circulate/break, forming positive/negative alternating pulse currents in the primary coil of the transformer.

  Main advantages: Compared with the push-pull structure, the primary winding is reduced by half, and the switch tube withstand voltage is reduced by half.

  The main disadvantages: the number of switch tubes used is large, and the parameter consistency is required to be good, the drive circuit is complicated, and it is difficult to achieve synchronization. This circuit structure is usually used in ultra-high-power switching power supply circuits above 1KW.

  5, half bridge

  The structure of the circuit is similar to the full-bridge type, except that the two switch tubes (T3, T4) are replaced with two equivalent large capacitors C1 and C2.

  Main advantages: Has a certain degree of anti-unbalance ability, and the circuit symmetry requirements are not very strict; It can adapt to a large power range, from tens of watts to kilowatts; the switch tube has a lower withstand voltage requirement; the circuit cost is higher than that of a full-bridge circuit Inferior. This kind of circuit is often used in various non-regulated output DC converters, such as electronic fluorescent lamp driving circuits.


Read recommendations:

MKS-120200BS-36 Switching Power Supply

EI-28 AC ADAPTER LINEAR ADAPTOR Linear Power Adapter Switching Power Adapter Linear Adapter

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

Oil-immersed transformers should pay special attention to their fire safety measures

Design and analysis of over-temperature protection circuit

Related Information

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

Select the power adapter to determine these three adaptation conditions.SWITCHING POWER Vendor

2022-04-11

Why is the original power adapter better than the non-original one?TRANSFORMER Production

2022-04-09

What are the industries where the power adapter can be applied?CAR CHARGER wholesale

2022-04-08

What is the difference between high-end and low-end power adapters? How to check after playing,CAR P

2022-04-07

How to design a good power adapter,CAR CHARGER wholesaler

2022-04-07

Customized desktop power adapter

2022-04-06

The quality of the switching power supply determines the safety of electricity use,CAR CHARGER whole

2022-04-02

What are the advantages of wireless chargers?

2022-03-30

PD charger is a must-have at home

2022-03-29

What are the main materials of the power adapter shell?

2022-03-26

What is a PD power adapter? It can make charging ubiquitous

2022-03-25

Slow charging? Try a fast charger

2022-03-24

Do you understand the cause of abnormal noise in the power adapter?

2022-03-23

Reasons for abnormal noise of the power adapter

2022-03-22

Talking about the common problems of the power adapter

2022-03-19

General manufacturer power adapter reliability test items

2022-03-18

More energy efficient and safe power adapter

2022-03-17

Five ways to solve the power adapter overheating?

2022-03-16

What are the common connection faults of cottage shared chargers on the market?

2022-03-15

How to use the car charger and matters needing attention!

2022-03-14

Do you know the difference between a power adapter and a charger,CAR CHARGER Processor

2022-03-12

The power adapter has a very wide range of applications,Audio Transformer

2022-03-11

What is the development trend of the power adapter industry,AC ADAPTER

2022-03-10

Popular recommended products

3-15W Switching Power Supply

2020-08-28

MKS-1401700H Switching Power Supply

2020-08-29

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

2020-08-27

500W Charger,Charger

2020-08-28

MKS-120200EU-36 Switching Power Supply

2020-08-29

MKS-1202000-36 Switching Power Supply

2020-08-29

EI-48 ADAPTER LINEAR ADAPTOR Switching Power Adapter INTERCHANGEABLE ADAPTOR Linear Adapter

2020-08-28

ER42 High Frequency Transformer

2020-08-27

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

2020-08-27

MKS-120200BS-36 Switching Power Supply

2020-08-29

24W USB Charger,24W Charger,USB Charger

2020-08-27

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

2020-08-27

24V1.5A 36W Switching Power Supply

2020-08-29

30W PD Charger,30W Charger,PD Charger

2020-08-27

3-8W Charger,3W Charger,8W Charger,4W Charger,5W Charger,6W Charger,7W Charger

2020-08-27

24-65W Switching Power Supply

2020-08-29

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

2020-08-27

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

2020-08-28

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

2020-08-28

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

2020-08-27

24-36W Charger,36W Charger,24W Charger,30W Charger

2020-08-27

36-65W Switching Power Supply

2020-08-29

EI-28 AC ADAPTER LINEAR ADAPTOR Linear Power Adapter Switching Power Adapter Linear Adapter

2020-08-28

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

2020-08-27

24-65W Medical Switching Power Supply

2020-08-27

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

2020-08-28

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

2020-08-28

19V2A 36W Switching Power Supply

2020-08-28

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

2020-08-27

EI-41 ADAPTER AC ADAPTER LINEAR ADAPTOR SWITCHING ADAPTOR Linear Adapter

2020-08-28
Copyright 2020 © Merryking Technology Co., Ltd. All rights reserved