Application examples of self recovering fuses
1. Ballast
Fluorescent lamps require ballasts to generate high voltage and high current for ignition. The ballast controls the electrical characteristics of fluorescent lamps.
When the lamp is turned on, the electronic ballast generates high voltage impact at both ends of the lamp, igniting the lamp. A self oscillating circuit is formed in the electronic ballast, controlled by transistors.
Many electronic ballasts fail due to lighting. When the lamp short circuits, reaches its service life, or is removed, overcurrent situations may occur, which will cause the cathode of the lamp to open.
Due to power factor, the load resistance decreases. During startup, the ballast operates more than three times under abnormal operating current and high oscillation frequency; The switch circuit generates overcurrent and causes ballast failure.
2. Cordless phone battery
The current and voltage of cordless phones are relatively small. SRP120, LTP070, and LTP100 are all excellent overcurrent protection components.
3. Wireless communication battery
The current used for wireless communication is greater than that of mobile phone batteries and less than that of laptops. The LR4 series has a working current of 7.3 amperes, small size, and light weight, making it very suitable for this application. The SRP or LTP series with high working current are also applicable.
4. Chemical battery
The application of chemical batteries is becoming increasingly widespread, and the use of these components will enable battery packs to have better protective devices at lower costs.
(1) Nickel cadmium battery
NiCD batteries with low impedance and stable chemical properties are less sensitive to overcurrent than NiMH and lithium-ion batteries.
But due to low losses, it is still widely used. However, under short-circuit or overcurrent conditions, their low internal resistance will result in higher current passing through.
Usually, the cause of battery failure is overcurrent, not overheating, and they are suitable for products using any battery material.
(2) Nickel hydrogen battery
Nickel hydrogen batteries have a higher energy density than nickel cadmium batteries.
When it exceeds 90C, these batteries are more prone to degradation.
VTP or LTP materials are more suitable for protecting this type of battery than SRP/LR4 materials.
According to battery design methods, both SRP and LR4 can protect the battery, but LTP and VTP have stronger thermal conductivity.
(3) Lithium ion battery
Among all chemical batteries, lithium-ion batteries have the highest energy density and the most sensitive chemical properties.
Circuit protection devices are required for use and charging.
The general protective device is an integrated circuit, but this is not the safest because the integrated circuit itself may also cause short circuits or CMOS startup failures, making the protective device unsafe.
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