What are the thermal insulation materials for the power adapter?
Power Adapter
Power adapter is a power supply conversion device for small portable electronic devices and electronic appliances. It is widely used in mobile phone handsets, game consoles, language repeaters, walkmans, notebook computers, cellular phones and other equipment. The power adapter is generally composed of a shell, a power transformer and a 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 adapters are widely used in industrial automation control, military equipment, scientific research equipment, LED lighting, industrial control equipment, communication equipment, power equipment, instrumentation and other fields.
Since a large number of high-power semiconductor devices are used in power adapters, such as bridge rectifiers, high-current rectifiers, high-power transistors or field effect transistors, they will generate a lot of heat when they work. Once the power supply temperature exceeds 75°C, If the heat cannot be discharged in time and kept at a reasonable level, the normal operation of the power adapter will be affected, and the power adapter will be damaged in severe cases. Generally, power adapter manufacturers use some thermally conductive insulating materials to help the power supply dissipate heat during the design and production. What are the commonly used thermally conductive insulating materials for power adapter cooling solutions?
Thermally conductive potting glue
Thermally conductive glue potting is divided into partial potting and overall potting. The inside of the power adapter is uneven and irregular. What is needed is a thermally conductive material that can completely wrap the transformer and cannot move at will. Local potting is generally concentrated when the heat is large and cannot be replaced by other thermally conductive materials. The whole potting is because part of the power supply has to work outdoors for a long time. In addition to solving the heat dissipation problem, the waterproof and airtightness of the power supply must also be considered. Therefore, the outdoor power supply basically uses the overall potting to dissipate heat.
Thermally conductive silicone sheet
For the power supply industry, the proportion of thermal silica gel applications is usually small, but sometimes it is indispensable. Generally, the application of thermal silica gel films for power adapters is mainly concentrated on the PCB board. A special application and demand must There will be a special supply to meet it. The thermally conductive silicone sheet is applied to the PCB board, which has high thermal conductivity, electrical insulation, shock and puncture resistance and other functions, which can effectively solve the safety problem for the client.
One-component silicone
One-component silica gel is usually used for local heat conduction of power supply components, and at the same time it can play a role of fixing components. It has good adhesion and sealing properties to metals and non-metals.
Thermally conductive silicone cloth Generally used in power MOS tube packaging, conventional standard parts TO-220, TO-3P, etc., usually apply a layer of silicone grease on the silicone sheet and MOS tube to increase the adhesion and reduce the thermal resistance.
Alumina ceramics
Whether it is thermal conductivity, temperature resistance range or insulation performance, it far exceeds thermal conductivity silicone cloth, which can be used to replace the position of silica gel in the MOS tube. There are standard parts for the TO-220 and TO-3P series, which need to be increased by applying silicone grease. The contact area of the MOS tube.
