Energy saving power adapter, switching power supply in the application of self recovery fuse
Energy saving power adapter, switching power supply in the application of self recovery fuse - 2017
12 author: click: energy-saving power adapter, switching power supply in the application of self recovery fuse 1.
The characteristics of the self recovery fuse self recovery fuse is introduced in the 1990 s a new type of over current protection device.
Traditional fuse is one-time overcurrent protector, need to be replaced after fusing, equipments to work properly, is not convenient to use.
Made of polymer mixed with conductor and self recovery fuse, successfully solve the problem.
It has small volume, variety specification is complete, switch features good recovery, and repeated use, don't need maintenance, etc.
Products are divided into wafer type according to their shape, square, miniaturization of SMT type.
Since the recovery fuse switch characteristics, also known as the polymer switch.
Internal by polymer in high pressure, high temperature, curing reaction conditions, after mixed with conductive particle materials, through special process.
Due to conductive polymer chain tightly bound on the crystalline structure, so the normal resistance is very low, only a fraction of the ohm, the working current through the heat produced during the fuse is very small, will not change the crystalline structure of the polymer inside.
When short-circuit fault occurs, the current increases sharply, heat conductive chain made from crystalline polymer gel into amorphous form colloid, originally bound spontaneously separation of conductive chain rupture, components of resistance is several orders of magnitude increase rapidly, presents the open circuit state, immediately to the current be cut, the protection.
After once current fault expelled, components quickly back into a state of low resistance.
It is this 'low resistance' or 'high impedance' sustainable transformation, not only can use repeatedly and replaced.
Since the restoration of fuse resistance and temperature, which is divided into the following several stages.
When temperature increases, its heat and heat to achieve dynamic balance.
Even if the current larger or the environment temperature, increase the heat still can send out into the air.
If the current increases further, until the calorific value is greater than the heat release, since the restoration of fuse temperature will rise rapidly, small temperature variation can cause resistance increases sharply, blocking current through, to protect equipment from damage.
In a few seconds after the over current protection, with the reduction of temperature resistance and decreases rapidly.
Note: since the recovery fuse with PTC thermal properties, but with positive temperature coefficient thermistor has essential difference.
It belongs to the polymer -
Conductor and the PTC element is composed of barium titanate and rare earth elements sintering ceramic material, in addition of PTC element is at room temperature resistance value is bigger, fuse is not used.
Typical applications since the recovery fuse can be widely used in switching power supplies, chargers, electronic instruments, household appliances, computers and communications equipment, automatic protection effect.
Will be resumed from the fuse series directly in the single-chip switching power supply dc output side, the over-current protection function can be realized.
In satellite TV receiver equipment, generally using a coaxial cable transmission of television signals.
When a user of coaxial cable outlet short circuit fault occur, to form the phenomenon of over current, easy to damage the components of the television, therefore in the power of the TV series a self recovery fuse, once appear over current fault, since recovery fuse into a high impedance state, can effectively protect the TV set, and when the failure recovery after being ruled out it, do not affect the normal work of the TV set.
On the unit of automatic alarm system, all needs to add over-current or overheat protection circuit, can be used self recovery fuse, which can avoid any cell damage due to flow or overheating.
If the self recovery fuse in series between the charger and battery pack, can prevent the battery charged due to excessive, external short circuit fault and damage or overheating.
When the motor load, plugging in turn cause overheating, it is easy to burn the motor, self recovery fuse in series with the back of the rectifier, starting to dc motor protection.
The self recovery fuse series in stereo speakers water girl, when over current to protect the speaker will not damage, and the power loss caused by restore the fuse less than 0.
1 db, and there is no inductance and capacitance effect, also won't cause distortion in audio frequency range.
Pieced the self-healing fuse into the secondary winding circuit of power transformer, to multiplex stabilized voltage supply for their own protection.
Use it to replace the insurance tube in the digital multimeter, which is the most suitable solution, often there is no need to change the fuse insurance tube.
The energy saving power adapter