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Dual MOSFET gate drivers.

Akarsh Gopal
Prodigy 80 points
Other Parts Discussed in Thread: UCC21520

Hello

I need to drive two different MOSFETs( not half bridge), one high side and one low side( where the drain of the second MOSFET is connected to the Drain of the first). This is for a PFC followed by a buck converter.Hence the two MOSFETs sharing a common Drain voltage.

I wanted to know if TI has any integrated solution for driving two MOSFETs as I have explained, without them having to be in a half-bridge config.

Also, does TI have an integrated current shunt sense amplifier in any of these solutions to the above issue.

Thanks.

  • 0
    TI__Intellectual 2061 points
    Hello Akarsh,
    Thanks very much for your intesest on TI gate drivers.
    For you application and question, here are a few comments:
    1. Can you please give a picture or drawings showing the system toplogy, so that we could understand better? I understand boost PFC followed by a buck. can you please help confirm you have no DC link capacitor after your boost PFC?
    2. UCC21520 should be able to serve your request. however, we need to find a way to generate the decent power supply for each rail.
    3. Unfortunately, I am not aware of any TI driver with integrated shunt sense amplifier. However, it should be easy to implement with external operational amplifier.
    Please feel free to let me know if you have any further questions.
    Wei
  • 0 in reply to Wei Zhang
    Prodigy 80 points
    Hello Wei

    Sorry, the two MOSFETs don't share the same voltage at Drain, there's a diode in between.
    1.A circuit that is similar to one the I was referring to :
    www.powerguru.org/.../Functional-Blocks-of-an-Electronic-HID-Ballast.jpg
    ( Please disregard the full-bridge output at the end, my circuit ends at the buck converter out.)
    As for the DC link capacitor after boost PFC, there is one.
    2.Okay, will look into this. As for the power supply, I'm planning to use this circuit to charge a li-ion battery pack, so I should be able to do something with that.
    3. Okay, I'll go ahead and use the external Op-Amp or a current sense amplifier.

    If you have any suggestions regarding a better topology/schematic for charging a 4kWh li-ion battery pack at around 3.6 KW from a 230V AC source , do let me know.
    Thanks, if I have further questions, I will definitely get back.

    Akarsh
  • 0 in reply to Akarsh Gopal
    TI__Intellectual 2061 points

    Hello Akarsh,

    Thanks very much for your information.

    Is your circuit isolated from AC to Battery? if so, or you are using a fixed frequency LLC for isolation and have a buck for current and voltage regulation? which is BoostPFC+LLC(fs=fo)+Buck?

    Wei

  • 0 in reply to Wei Zhang
    Prodigy 80 points
    Hello Wei

    Hmm, the circuit isn't isolated from AC to battery. Would this be necessary for any particular reason? I lack any experience in this regard since this is my first attempt in designing such a circuit. I assumed rectification of AC, then boost PFC and then regulating the current and voltage via a buck converter would do the job for a battery charger. Please let me know if I'm wrong. If possible, could you help me improve/correct this circuit?
    I'm trying to charge a li-ion battery pack of 96V( from 72V-96V), 42Ah at 3.6kW power with the grid(220V, 50Hz AC) as source.

    Thanks
    Akarsh Gopal
  • 0
    TI__Mastermind 23215 points
    Hello Akarsh,

    From you description, I assume at lease one of the drivers needs to have a floating high side bias supply. It is not clear about the second MOSFET drive. The most versatile solution for a dual driver is an isolated two channel driver such as the UCC21520. The two drivers can be independently controlled, and the two driver side channels are isolated and have independent ground and bias supplies.