The role and selection of thermistor in switching power supply

Thermistor is a kind of resistor device that can change the resistance value with the change of ambient temperature. In the switching power supply, thermistor is mainly responsible for temperature protection and voltage stabilization function, which plays a vital role.

First of all, one of the functions of thermistor in switching power supply is temperature protection. Switching power supply in the working process will produce a certain amount of heat, if the heat can not be distributed in a timely manner, it will lead to the switching power supply temperature rises too quickly, and in serious cases may cause fire and other safety hazards. In order to prevent this from happening, a thermistor can be added to the switching power supply and the temperature change can be monitored by the thermistor. When the temperature exceeds a certain threshold, the thermistor will change its resistance value, thus triggering the protection circuit to cut off the circuit or reduce the current flow through it to realize the temperature protection function.

Secondly, thermistor can also play the function of voltage stabilization in switching power supply. Switching power supplies generally need a stable output voltage to ensure that other electronic components in the circuit work properly. However, in some cases, switching power supplies can be affected by the external environment, such as temperature changes and power supply fluctuations, which can lead to fluctuations in the output voltage. In order to eliminate these effects, a thermistor can be used to realize feedback control, monitor changes in the output voltage, and keep the output voltage stable by adjusting circuit parameters.

When selecting thermistors, a series of factors need to be considered to meet the requirements of switching power supplies.

First, select the appropriate resistance value. The resistance value of thermistors changes with temperature, so it is necessary to select a suitable resistance value according to the set temperature range and accuracy requirements. Generally speaking, the larger the resistance value of the thermistor, the worse the heat dissipation ability and the higher the sensitivity.

Second, consider the operating temperature range of the thermistor. The operating temperature range of the switching power supply is an important parameter, and it is necessary to select a thermistor with a matching operating temperature range. If the operating temperature range of the selected thermistor does not meet the requirements, it may lead to failure of the temperature protection function or unsatisfactory voltage regulation.

In addition, the stability and response speed of the thermistor need to be considered. Stability refers to the resistance value stability performance of the thermistor in long-term use, and response speed refers to the response speed of the thermistor to temperature changes. In the selection process, the thermistor with good stability and fast response speed should be selected to ensure its reliability and real-time.

In addition, the precision and power consumption of the thermistor need to be considered. Precision refers to the deviation between the resistance value of the thermistor and the actual temperature, and power consumption refers to the power consumed by the thermistor in the working process. In the selection process, the thermistor with appropriate precision and power consumption should be chosen according to the specific application requirements to ensure the working effect of the system.

In summary, thermistors play a vital role in switching power supplies by assuming the functions of temperature protection and voltage stabilization. In the selection process, it is necessary to comprehensively consider the resistance value, operating temperature range, stability, response speed, precision and power consumption to select the appropriate thermistor to meet the requirements of the switching power supply.