What is the typical over temperature protection for a power supply?
The over temperature protection temperature setting of the power supply may vary depending on the device type, application scenario, power supply, and manufacturer’s design standards. The following is a rough range and related explanation of the over temperature protection temperature for common electronic device power supplies:
1、 Over temperature protection temperature range for common electronic device power supplies
Equipment type over temperature protection temperature range (℃) description
The laptop power supply has a built-in temperature sensor at 70-90 ℃, which triggers protection when the shell temperature exceeds the threshold, avoiding the risk of overheating of components such as lithium batteries.
Mobile phone charger 65~85 ℃ fast charging charger may have a higher protection threshold (such as 80~85 ℃) due to its high power, while ordinary chargers usually have a protection threshold of around 70 ℃.
The PC power supply (ATX) relies on internal heat dissipation design for temperatures between 60~80 ℃, while high-power power supplies (such as 800W and above) may have lower thresholds set (such as 60~70 ℃).
To ensure long-term stable operation and low protection threshold, some devices may initiate frequency reduction or warning around 50 ℃ for servers/industrial power supplies at 50-70 ℃.
Lithium battery chargers with a temperature range of 45~60 ℃ have strict protection thresholds to prevent explosions caused by overcharging and overheating. Some products trigger protection at temperatures above 45 ℃.
Switching power adapter 75~95 ℃ Small adapters (such as routers and displays) may have higher thresholds due to limited heat dissipation space, but it is necessary to avoid exceeding the temperature resistance limit of the components.
2、 Key factors affecting over temperature protection temperature
Temperature resistance of core components
The maximum operating temperature of internal capacitors, MOSFETs, transformers, and other components in the power supply determines the protection threshold. For example, electrolytic capacitors usually have a temperature resistance of 85 ℃ or 105 ℃, and the protection temperature will be lower than their limit value (such as set to 80 ℃ or 100 ℃).
Example: Using a power supply with a temperature resistant 105 ℃ capacitor, the over temperature protection may be set to 95-100 ℃; And ordinary capacitor power supplies may be set at 75-85 ℃.
Heat dissipation design and ambient temperature
Natural heat dissipation (fanless): Due to poor heat dissipation, power supplies (such as mobile phone chargers) have a lower protection threshold (65-80 ℃) to prevent the shell from getting hot.
Active cooling (with fan): PC power or server power is cooled by a fan, and the protection threshold can be appropriately increased (70-85 ℃), but buffer space needs to be reserved in case of fan failure.
Environmental temperature: In high temperature environments (such as above 40 ℃), the power protection threshold may be lowered by 5-10 ℃ to prevent cumulative overheating.
Safety standards and vendor strategies
International standards such as UL and CE require that power supplies must trigger protection in case of abnormal temperature rise to avoid the risk of fire. Manufacturers may adjust thresholds based on product positioning:
Consumer grade products: prioritize user safety, with a conservative threshold (such as 75 ℃ for mobile phone chargers).
Industrial grade products: focus on stability, may allow for higher temperatures (such as 85 ℃), but need to be accompanied by warning mechanisms (such as increasing fan speed).
3、 Trigger mechanism and response measures for over temperature protection
Trigger mechanism
Temperature sensor: Built in NTC thermistor or thermocouple, real-time monitoring of key component temperature.
Control logic: When the temperature exceeds the threshold, the power supply will automatically enter the following states:
Power reduction mode: Reduce output power (such as switching from fast charging to slow charging) to minimize heat generation.
Pause output: completely turn off the power until the temperature drops (such as when the laptop power red light flashes).
Alarm prompt: Some devices (such as servers) will alert users through LED lights or software error messages.
User response measures
Avoid blocking the heat dissipation holes: Ensure good ventilation around the power supply, especially in summer or enclosed environments.
Check the operation of the fan: If the power supply with a fan stops running, clean the dust or replace the fan in a timely manner.
Replace aging power supply: Power supplies that have been in use for more than 5 years may experience frequent triggering of overheating protection due to component aging. It is recommended to regularly inspect or replace them.
4、 Over temperature protection in special scenarios
Automotive power supply (12V/24V system)
The over temperature protection is usually set at 60-75 ℃ to avoid circuit faults caused by high temperature environments (such as near the engine compartment).
New energy charging station
The over temperature protection threshold of DC fast charging piles is relatively low (50~65 ℃), and due to the intense heating during high current charging, rapid response is required to ensure battery safety.
Outdoor power supply (energy storage power supply)
Balancing portability and heat dissipation, the protection threshold is mostly between 65~80 ℃, and some products are equipped with temperature display function for convenient user monitoring.
summarize
The core of power over temperature protection is to strike a balance between component safety, user experience, and device stability. If the power supply frequently triggers over temperature protection, it may be caused by poor heat dissipation, component failure, or excessive load. It is necessary to promptly investigate the cause to avoid safety hazards caused by overheating. For the power supply of specific devices, it is recommended to refer to the manual or consult the manufacturer for accurate protection threshold data.
