Precise Flow Control + Automatic Recovery: Technical Analysis Of Atlink's Resettable Fuse Circuit Solution

Fuse Elements - Theoretical Overview

The technology of polymer positive temperature coefficient (PPTC) materials and components is a process engineering that integrates advanced polymer material science, conductive material science and innovation, and is designed based on the basic theory of electronic motors.The resistance of such materials and components will increase dramatically as the temperature rises.

When overcurrent and overvoltage occur at the same time or either situation occurs alone, heat energy (energy E = current I × voltage V) is generated according to electrical principles, and the components generate heat.Such heating conditions will cause the structure of the polymer to change from a crystalline phase to an amorphous phase structure, causing the element resistance to increase by more than tens of millions of times, thus causing a trip/open state, thereby protecting the circuit.When the overcurrent condition is eliminated, the heat energy disappears and the resistance of the component returns to its normal state.

How a resettable fuse works

The design and manufacturing of Atlink's resettable fuses are independently developed by the company based on the polymer positive temperature coefficient (PPTC) material that has obtained multiple patent rights.Use electrodes or wires to attach to both sides of the PPTC material and protect the circuit in series with the circuit.

Under normal operating conditions, the resistance value of the element is at an extremely low state (micro-ohm), and current can pass through the PPTC element without limit; however, when an overcurrent condition occurs, the PPTC element will heat up and cause the resistance value to rise rapidly.

When the resistance value rapidly rises to an almost insulating state, the current on the circuit will be cut off to protect other mechanisms and components on the circuit until the overcurrent condition is removed. After the PPTC component cools, its resistance value drops to a value close to its initial value.At this time, the resettable fuse (PPTC) returns to a state where it can pass current again.

PPTC Hold/Trip Current & Thermal Derating Curve

The trip current (IT) and operating current (IH) values of Atlink's resettable fuse are defined under the environmental conditions of 23 degrees Celsius.Generally speaking, the trip current is about twice the operating current.

Atlink's PPTC products will not enter the open circuit/trip state when used at normal working current (IH) or lower than the working current; but will enter the open circuit/trip state when the trip current (IT) is above or higher than the trip current.

However, due to the positive temperature coefficient (PTC) effect, the trip current and operating current will change drastically as the ambient temperature changes.For example, as shown in the figure below, the current will decrease to 50% at 85 degrees Celsius, and will increase to 150% at -40 degrees Celsius. 

Atlink product series

Atlink products are designed according to the needs of today's electronic and motor industry; their reusable features, small size, versatile shapes, extremely low heat dissipation, and extremely competitive prices are incomparable to traditional fuses, ceramic positive temperature coefficient fuses, bimetallic fuses, and current-limiting integrated circuits, and are most suitable for application in low-voltage DC or AC power supplies.Baodian Tongke Technology's refillable fuses are available in many different shapes, including: plug-in type, sheet type, surface-adhesive type, and customer-specific specifications.

Safety, quality and customer satisfaction

Through UL, C_UL (CSA) and certification, the long-term safety and superior use characteristics of Atlink products have been proven.From the beginning of product design and research and development, we follow the ISO 9000:2000 quality management system to ensure the efficient quality and consistency of our products.

Adhering to continuous innovation and improvement, we promise to provide customers with the highest quality products and the best services to achieve and satisfy their most ardent needs.We firmly believe that in order to gain a foothold in the world and remain invincible in tomorrow's global business competition, a close strategic alliance between our customers and us is the only and best way.

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