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UCC27712: How to achieve HO have PWM and LO always low?

Part Number: UCC27712
Other Parts Discussed in Thread: SN6501

Hi team,

The customer application only need  HO has duty output but LO always low.

How can we implement that in H/W without trigger UVLO?

The UCC27712 has an internal under voltage-lockout (UVLO) protection feature on the supply circuit blocks between VDD and VSS pins, as well as between HB and HS pins.

 

Thanks and best regards,

Jamie

  • Hello Jamie,

    The driver logic will work with no issue just driving the HI input and HO output without LO being active. Depending on the converter, or power train, there is a concern if the high side bias supply can be maintained using a bootstrap diode and capacitor.

    If the power train switch node will not switch to ground, to allow charging the boot capacitor, a floating high side bias can be used to provide the bias for the HB-HS. Below is a simple diagram using the SN6501 transformer driver which is a simple solution for the bias.

    Regards,