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Original question:

[FAQ] UCC27211A: What's the difference of UCC27211A and UCC27211

UCC27211A: output status when enter into UVLO

Given Ding
Genius 10155 points
Part Number: UCC27211A

Hi Team,

Here is a question from customer. 

In customer's application, they use a controller co-work with UCC27211A. And when powering off, UCC27211A will enter into UVLO first, and then the controller enter into UVLO, that means, when UCC27211A enters into UVLO, there is still PWM input. So customer has concern on the output status of UCC27211A at such condtion to see if it affect the total sys. below are some conditions customer can think of  and if there is other condition, please kindly also list.

 1. PWM is high. For example

     a.  HI is high and 27211A enter into UVLO, then what's the status of HO? Is it HIGH or LOW? 

     b.  HI is high and 27211A enter into UVLO, then 27211A recovers, what's the status of HO? does it change to LOW when enter into UVLO then go to HIGH when recover? 

2. PWM is low. For example, 

   a.  HI is Low and 27211A enter into UVLO, then what's the status of HO? Is it HIGH or LOW? 

Looking forward to your reply and thanks. 

BRs

Given 

  • 0
    TI__Mastermind 23155 points

    Hello Given,

    When the UCC27211A enters UVLO, the outputs will go low even if the driver inputs are high.

    The VDD UVLO (off) will disable the LO and HO outputs, regardless of the inputs. If VDD is above UVLO and the HB-HS bias is below the UVLO threshold the HO output will be forced low.

    If the driver inputs are high, and stay high when the bias enters UVLO the driver outputs will be forced low. When the bias recovers if the inputs are still high the outputs will go to the high state as determined by the driver inputs.

    Confirm if this addresses your questions, or you can post more questions on this thread.

    Regards,