Thermal protection is a method of detecting over-temperature conditions and disconnecting the power to the electronic circuits. The protection prevents fires or damage to electronics components, which may arise due to the excess heat in the power supplies or other equipment.
Temperature in power supplies rises due to both environmental factors as well as heat generated by the components themselves. The amount of heat varies from one power supply to another and may be a factor of design, power capacity and load. Natural convention is adequate for removing the heat away from smaller power supplies and equipment; however, forced cooling is required for larger supplies.
When the devices operate within their safe limits, the power supply delivers the intended power. However, if the thermal capacities are exceeded, the components start deteriorating and eventually fail if operated under excess heat for long. The advanced supplies and electronic equipment have a form of temperature control in which the equipment shuts down when the component temperature exceeds the safe limit.
Devices used to protect against over-temperature
There are different methods of protecting power supplies and electronics equipment from over temperature conditions. The choice depends on the sensitivity and complexity of the circuit. In complex circuits, a self resetting form of protection is used. This enables the circuit to resume operation, once the temperature goes down to normal.