Views: 957 Author: Site Editor Publish Time: 2022-09-27 Origin: Site
Power adapter is a power conversion equipment for small portable electronic equipment and electronic appliances. It is widely used in telephone mother machine, game machine, language repeater, Walkman, notebook computer, cellular phone and other equipment. Power adapter is generally composed of shell, power transformer and rectifier circuit. According to its output type, it can be divided into AC output type and DC output type; According to the connection mode, it can be divided into wall type and desktop type. Power adapter is widely used in industrial automation control, military equipment, scientific research equipment, LED lighting, industrial control equipment, communication equipment, power equipment, instruments and other fields.
Because a large number of high-power semiconductor devices are used in the power adapter, such as rectifier bridge, high-current rectifier, high-power triode or field effect transistor, they will produce a lot of heat when they work. Once the power supply temperature exceeds 75 ℃, if these heat can not be discharged in time and kept at a reasonable level, It will affect the normal operation of the power adapter and damage the power adapter in severe cases. Generally, power adapter manufacturers will use some thermal insulation materials to help the power supply dissipate heat during design and production. What are the commonly used thermal insulation materials in the heat dissipation scheme of power adapter?
Thermal conductive adhesive
Thermal conductive adhesive is divided into local potting and overall potting. The interior of the power adapter is uneven and irregular. What is needed is a heat conductive material that can completely wrap the transformer and can not be moved at will. Local potting is generally concentrated in the case of high calorific value and can not be replaced by other heat conducting materials. Integral potting is because some power supplies have to work outdoors for a long time. In addition to solving the problem of heat dissipation, we should also consider the waterproof and sealing of the power supply. Therefore, outdoor power supplies basically adopt integral potting for heat dissipation.
Thermal conductive silicon pad
thermal conductive silicon pad usually has a small proportion of applications for the power industry, but sometimes it is indispensable. Generally, the application of thermal conductive silicon film for power adapter is mainly concentrated on PCB board. A special application and demand will have a special supply to meet it. Thermal conductive silicon film is applied on PCB board, which has high thermal conductivity efficiency Electrical insulation, shockproof, puncture proof and other functions can effectively solve the safety problems for the client.
Single silica gel
Single silica gel is usually used for local heat conduction of power components, and can also play the role of fixing components. It has good adhesion and sealing for metal and non-metal.
Thermal conductive silicon pad is generally used for power MOS tube packaging. Conventional standard parts TO-220 and to-3p are usually coated with a layer of silicone grease on silicon film and MOS tube to increase adhesion and reduce thermal resistance.
Alumina ceramic
Whether it is thermal conductivity, temperature resistance range or insulation performance, it is far superior to thermal conductive silicone tape, which can be used to replace silica gel in MOS tube. There are standard parts for TO-220 and to-3p series, and the contact area with MOS tube needs to be increased by coating silicone grease.