What is the overcurrent protection circuit?

Circuit is the safe place for stable operation of electrical appliances in our life. There are many types and forms of circuits, and various protection elements are often used in the circuit to ensure power supply. So what is theovercurrent protection circuit? Follow Xiao Bian to have a look

Overcurrent protection circuitIntroduction

Overcurrent protection is realized by connecting quick fuses in series in the circuit. It is applicable to thyristor and GTO because they have higher surge current withstand capacity. For MOSFET, GTR and IGBT, due to the low overcurrent capacity, special overcurrent protection circuit is required. The overcurrent protection circuit is required to complete overcurrent detection, signal transmission and protection actions in an instant and microsecond. The internal current is limited by the overload capacity. At present, the commonly used methods include monitoring method and current sensor protection method

Definition of overcurrent protection: Many electronic devices have a rated current, which is not allowed to exceed the rated current, otherwise the device will be burned. So some devices have current protection modules. When the current exceeds the set current, the equipment will automatically cut off the power supply to protect the equipment. For example, the main board usb generally has usb overcurrent protection to protect the main board from burning

Overcurrent protection circuitPrinciple

When the power supply has inter-phase short circuit fault, the grid current will suddenly increase and the voltage will suddenly drop. Overcurrent protection is to set the working current of current relay according to the requirements of line selectivity. When the fault current in the line reaches the action value of the current relay, the current relay acts according to the selection requirements of the protection device and selectively cuts off the fault line

Effect: a material has PTC effect, that is, positive temperature coefficient effect, which only means that the resistance of the material will increase with the increase of temperature. For example, most metal materials have PTC effect. In these materials, the PTC effect is characterized by a linear increase in resistance with temperature rise, commonly referred to as the linear PTC effect

Overcurrent protection circuit is the main method of circuit protection. Overcurrent protection also provides protection for the use of circuit insurance to ensure less loss of circuit equipment and protect equipment and personnel