Power Supply Thermal Management
The power supply will generate heat during operation, and the continuous temperature rise will cause performance changes, which may eventually lead to system failure; In addition, heat will also shorten the service life of components and affect long-term reliability. Therefore, power management also involves thermal management.
Thermal management follows the basic principles of physics. There are three ways of heat conduction: radiation, conduction and convection. For most electronic systems, the required cooling is to let the heat leave the heat source by conduction, and then transfer it to other places by convection.
In thermal design, it is necessary to combine various thermal management hardware to effectively realize the required conduction and convection. There are three most commonly used radiating elements: heatsink, heat pipe and fan. heatsink and heat pipe are passive cooling systems without power supply, while fan is an active forced air cooling system.
Heatsink Solution:
The heatsink is an aluminum or copper structure, which can obtain heat from the heat source through conduction and transfer the heat to the air flow (in some cases, to water or other liquids) to realize convection. There many kinds of heatsinks ,such as stamping sink, extrusion heatsink, skived fin heatsink, folder fin heatsink, soldering fin heatsink,etc .
The heatsink has no moving parts, lower operation cost, low failure mode . Once the radiator is connected to the heat source, as the warm air rises, convection will naturally occur, starting and continuing to form air flow. But the heatsink that transmits large heat has large volume, will have high cost and heavy weight, and must be placed correctly, which will affect or limit the physical layout of the circuit board.
HeatPipe Solution:
The heat source converts the working fluid into steam in the heat pipe, and the steam transfers heat to the colder end of the heat pipe. At this end, the vapor condenses into a liquid and releases heat, while the fluid returns to the hotter end. The gas-liquid morphology transition process is continuous and driven only by the temperature difference between the cold end and the hot end. Connecting a heatsink or other cooling device at the cold end can solve the heat dissipation problem of local hot spots with blocked air flow.
Fan solution:
In many cases, especially when the air flow path is curved, vertical or blocked, they are usually the only way to obtain sufficient air flow. The key parameter defining fan capacity is the unit length or unit volume flow of air per minute. However, physical size is a problem: a large fan with low speed can produce the same airflow as a small fan with high speed, so there is a trade-off between size and speed. Combined with heatsink module will always provide a good thermal performance in many applications.
Thermal management can reduce the temperature of components and internal environment in the power supply, prolong the service life of products and improve reliability. It involves the trade-offs of size, power, efficiency, weight, reliability and cost. The priorities and constraints of the project must be evaluated when doing the thermal design .
