Military Quality Of Power Adapters

How to Conduct Reliable Thermal Designs

Reasonable thermal design for power adapters not only brings the potential of semiconductor power devices into full play, but also improves the reliability of the power supply, reduces the cost of the power supply, shrinks the volume and reduces the weight. Therefore, the thermal design of the power adapter is an indispensable part of the power adapter design task.

Thermal design principles, one is to reduce losses, the correct choice of device parameters (current, voltage quota, on-resistance and switching characteristics) and magnetic component design, in addition to the selection of low-power devices, reduce the number of heat-generating devices, increase the width of coarser printed line to improve the efficiency of the power supply. The second is to strengthen the heat dissipation, that is, the use of conduction, radiation, convection technology to transfer heat, which includes the use of heat sinks, air-cooled (natural convection and forced air-cooled), liquid-cooled (water, oil), thermoelectric refrigeration, heat pipes and other methods.

The thermal design of power adapters includes the design of power semiconductor device heat sinks and the thermal design of switching power supply systems. Power semiconductor device heat sink design is the basic task, according to the basic principles of heat transfer, for power semiconductor device design a thermal resistance as low as possible heat flow path, so that the semiconductor device issued by the heat can be distributed through it as soon as possible, so as to ensure that the device is running, the internal junction temperature is always maintained within the allowable temperature range.

Power adapter switching power supply system heat dissipation design refers to the reasonable layout of the various units within the system, select the cooling method, so that the internal heat of the system can be emitted in a timely manner to avoid the emergence of a localized high heat zone. Forced air-cooled heat dissipation is more than ten times greater than natural cooling, but to increase the fan, fan power supply, interlocking devices, etc., which not only increases the cost and complexity of the equipment, but also reduces the reliability of the system, in addition to increasing the noise and vibration, and thus in general should try to use the natural cooling, rather than air-cooled, liquid-cooled cooling methods such as.

In the layout of components, should be placed in the downwind position of the heat-generating devices or in the upper part of the printed board, the heat sink using oxidized black process to improve the radiation rate, do not allow black paint coating. Spraying three-proof paint will affect the heat dissipation effect, need to appropriately increase the margin. The plane of the radiator mounting device is required to be smooth and level, and generally coated with silicone grease on the contact surface to improve thermal conductivity. Transformers and inductor coils should be selected with thicker wires to suppress temperature rise.

Eahunt masters the industry-leading power supply R & D and production experience, with a number of national technology patents, many years of power supply R & D and production experience, resulting in the military quality of power adapters.