• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 81 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

[FAQ] Gate Driver FAQ – Frequently Asked Questions:

UCC21750: Maximum DC bus this part can handle

Wei-Han Lai
Prodigy 50 points
Other Parts Discussed in Thread: UCC21750

Tool/software:

Assume we're using a standard 2 level H-bridge inverter. Given that the CMTI is within the specification, how do we interpret the insulation specifications to determine the maximum DC bus the IC can handle?

  • 0
    TI__Prodigy 170 points

    Hi Wei-Han,

    Based on table 6.6 Insulation Specifications, there is a specification on the maximum insolation working voltage, which has a max DC voltage of 2121 Vdc. That is for the standard isolation barrier. Considering other insulation specifications, table 6.3 in UCC21750 datasheet shows the applied voltage vs lifetime. This maybe be helpful for selecting a max DC voltage depending on the lifetime needed for the driver.

    Some other key parameters to look at is the external clearance and creepage. According to standard IEC60664, table F.5 shows the different voltages for the environment of your part. Selecting a pollution degree of 1 or 2 depends on the "sterility" of your circuit. Meaning if the device is covered in some conformal coding then the pollution degree is likely a 1. UCC21750 has a material group of 1. Based on these categories, the Vrms can be determined:

    For basic isolation, it is about 1.6 kVrms
    For reinforced isolation, it is about 800 Vrms

    If a creepage or clearance greater than 8mm is needed special consideration may be needed.

    Hope this helps.

    Best,

    Siara