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MOSFET selection for BOOSt converter

DEVITH T
Prodigy 60 points

hi

i am designing two boost converter

1. Vin= 12 V dc ,Vout=50 V dc ,I out(max)=1A

2. Vin= 50 V dc ,Vout=150 V dc ,I out(max)=.02A

Q1:  Which Power transistor i have to use ? Whether any tool available for selection of Power MOSFET?       (i have seen an tool for buck converter design but i need boost !!!!!!!!)

Q2:     I know that Vds >1.5Vout         and  Rds on should be very low  and Pd< 500mW (from calculation) any Power mosfet meets this criteria are available with TI or not?

Q3:  can i directly go for a boost  with Vin= 12 V dc ,Vout=150 V dc ,I out(max)=.02A? since it need a duty cycle of 94% whether it's possible to design?

 

thanks in advance

DEVITH T

Sr.Project Engineer ,

NIELIT

  • 0
    TI__Mastermind 18200 points
    Hello.
    I've reached out to our applications team regarding your question. I hope to have an answer for you shortly.

    Unfortunately, right now there is only an online FET selector tool for buck converters. I will definitely forward your interest in a boost converter tool to our web tools team. The goal is eventually to have a tool for FET selection for every application.
  • 0 in reply to Brett Barr1
    TI__Mastermind 18200 points
    Devith,
    See the response from our apps team below:

    "For Vout =150V, both FET and Diode need to be min 200..250V , to withstand the Ringing + switch node Voltage spikes.
    However, one of the main reasons that FETs are NOT good choices for HS position ( Boost Diode position) past 24Vout is the Reverse Recovery charge and Body Diode characteristics. Cheap Schottky diodes in the 200V range yield much better results.

    As a result, for Vout ≥24V boost converter, only LS position is preferred to be a Mosfet . For HS position, Schottky or Si Carbide Diodes are being used. Good Schottky Diodes range up to 200V, everything 400….1000V are Si Carbide Diodes.

    For 50V out, you can select a 100V FET for the LS position , but switch-node Ringing reduction in the form of an RCD clamp or Active Clamp are mandatory.

    For Boost converter, both the FET and the HS diode are susceptible to Avalanche BV failures."

    Here is a link to our 100V devices: www.ti.com/.../n-channel-mosfet-transistor-products.page