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UCC27210: UVLO function of high side driver

Part Number: UCC27210

Hi Expert,

I'm looking at the UVLO function of UCC27210. In my understanding, if HS is floating when UCC27210 power up, the differential voltage between HB and HS is unknown, so it may triggers VHB UVLO, then the HO is disabled. So to avoid VHB trigger UVLO when using UCC27210 in a buck topo, firstly customer should turn on the low side MOSFET, make HS connect to GND to charge BOOT capacitor to VDD-Vdiode, then customer can turn on the high side MOSFET. Is my understanding correct? Thanks.



  • Hi Jared, 

    That's correct. At startup, the HB-HS capacitor will initially be discharged, and it will charge when the low side FET turns ON. Notice that several pulses might be needed to fully charge the cap above HB-HS ULVO depending on the capacitance of the bootstrap capacitor and the ON time of the low side FET.

    Best regards,