News

Home  -  News  -  Industry News

Pulse start circuit

source:Industry News Popular:adapter release time:2021-06-18 09:25:38 Article author:sznbone

  The resistors R1 and R2 are usually the discharge resistors of the energy storage capacitors C1 and C2. After they are switched on, they cause current to flow into the capacitor C3, and the capacitor C4 of the auxiliary charger will discharge at this time.

  The voltage of C3 will increase until both ends of the diac reach the trigger voltage. The bidirectional two-pole thyristor will trigger and transfer part of the charge from C3 to C4, and the size of the transferred current is limited by the resistance R3.

Pulse start circuit(图1)

  Choose the appropriate capacitors C3, C4 and the voltage value of the bipolar thyristor, so that the required auxiliary charger voltage is gradually formed at both ends of C, and the converter starts to work through a normal soft start.

  Again, through D5 and additional winding positive feedback, the main transformer provides an auxiliary charger.

  As C4 is further charged and the voltage rises, the bipolar thyristor turns off. Because of the clamping action of ZD1 on C3, the voltage across the bipolar thyristor no longer reaches the trigger value.

  This circuit has such advantages:

  During the turn-on transient, a large current is provided, and there will be no excessive loss on the resistors R1 and R2. In the case that the first pulse of the converter fails to start (this situation rarely occurs), once C4 is discharged and C3 is recharged to the turn-on voltage of the bipolar thyristor, the start action will be repeated.

  The choice of bipolar thyristor is very important. It must be able to conduct the required conduction current, and the conduction voltage should be less than (V1-Vstart) and greater than (V1-V2) (where V1 is the clamping voltage of ZD1, Vstart is the starting voltage of the control circuit, and V2 is the converter C4 voltage during operation); otherwise, the lock will occur after the first pulse. It is feasible to replace the bidirectional triode with a small SCR and an appropriate gate drive circuit.


Read recommendations:

60W bare board power supply

151W bare board power supply

High efficiency and high quality 6.6w dc adjustable 3.3v 2a dc power supply

Three performance indicators to pay attention to when choosing a switching power supply

What is the principle of mobile phone wireless charger

Previous:Types of overvoltage protection Back to list Next:Advantages of Topow 12V1A adapters

The latest article

Related Products

The latest article

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

9 classification methods of switching power supply

2022-05-10

Advantages and disadvantages of switching power supply current mode

2022-05-10

Advantages and disadvantages of switching power supply current mode

2022-05-09

9 classification methods of switching power supply

2022-05-09

Characteristics and working methods of PFC regulated switching power supply

2022-05-07

Six maintenance rules for drone lithium batteries.manual charger power adapter

2022-05-07

Reasons for Inrush Current in Switching Power Supply Design.adjustable power adapter

2022-05-06

The optimal solution of drone power management solution!12w acdc power adapter

2022-05-06

Characteristics of Switching Power Adapter Transient Loads

2022-05-05