In Littelfuse circuit protection products, what kind of current is I in I²t?

Power Circuit Protection
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You may see a figure in Littelfuse circuit protection products called I²t and wonder what it’s signifying. What kind of current is the ‘I’ in I²t? Is it the input current, the output current, or the bus current?

As it turns out, the answer is none of the above. It is the transient inrush current during power on/off, for inductive loads, etc.

Littelfuse SIDACtor series part number P0220SALRP
Littelfuse SIDACtor series part number P0220SALRP640×640 41.7 KB

For example:

DigiKey Part Number P0220SALRPTR-ND
Manufacturer Littelfuse Inc.
Manufacturer Product Number P0220SALRP
Detailed Description 15V Off-State 150 A Ipp TVS Thyristor DO-214AA, SMB
Datasheet Datasheet

In the data sheet, the calculation method for peak current energy is provided.

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How is this Pulse Waveform defined?

  • The pulse current rapidly rises from 0 to reach 100% of the peak value, and the time corresponding to this process is tr.
  • The pulse current starts to decline from the peak value. When it drops to 50% (half value), the corresponding time is td.

Through I²t, we can estimate the energy of the pulse.

More Littelfuse circuit protection products

Littelfuse Circuit Protection products provide stable and reliable signal transmission guarantee for all kinds of precision electronic devices by virtue of their precise adjustment relationship with capacitance, dynamic resistance, etc. in terms of high-frequency characteristics, and their performance is excellent in the industry.

More Q&A on Littelfuse Circuit Protection Products Technology:

I. Questions Related to Component Characteristics

  1. What are the classifications of gas discharge tubes?

  2. Littelfuse new MOV+Sidactor thyristor vehicle charging solution technological innovations

  3. In Littelfuse circuit protection products, what kind of current is I in I²t?

  4. What are the differences between discharge tubes and metal oxide varistors?

II. Questions Related to Selection

  1. How to select metal oxide varistors for overvoltage protection?

  2. Do Littelfuse overcurrent protection fuses/circuit breakers have self-resetting function?

  3. The difference in the selection of overvoltage / overcurrent between AC and DC input terminals?

  4. When to Use PTC Resettable Fuses and Metal Fuses?

  5. What parameters differ between surface mount and through hole fuse selections?

  6. Under what general circumstances can AC components be directly used in DC circuits?

  7. Can the method of paralleling small-capacity fuses be used to achieve the purpose of fast fusing?

III. Questions Related to Applications

  1. What design requirements for overcurrent and overvoltage protection?

  2. In which fields are gas discharge tubes mainly applied? Do they have directionality?

  3. Are overcurrent and overvoltage protection for AC/DC power inputs used in charging piles?

  4. Can Littelfuse Circuit Protection Products Protect Against Overvoltage and Overcurrent?

  5. How to understand the fuse explosion-proof test?

  6. How to specifically know the time of time-delay fusing fuses?