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UCC5350-Q1: What do"tPWmin1" and "tPWmin2" mean?

Yoshiki Ochi
Genius 9555 points
Part Number: UCC5350-Q1

Hi team, 

Could you confirm if my understanding shown in lower for "tPWmin1" and "tPWmin2" correct?

  • tPWmin1 "No response at OUT where OUT <10% × VCC2"; this is deglitch filter time on IN+ and IN- pin when "OUT pin voltage" is lower than 10% of VCC2 voltage (meaning that OUT pin is in low state)". 
  • tPWmin2 "No response at OUT where OUT ≥90% × VCC2"; this is deglitch filter time on IN+ and IN- pin when "OUT pin voltage" is higher than "90% of VCC2 voltage (meaning that OUT pin is in high state)". 

Regards,
Ochi

  • 0
    TI__Mastermind 23206 points

    Hi Ochi-san,

    This specification pertains to the "minimum pulse width" that will pass through the gate driver. Both a minimum positive pulse and a minimum negative pulse are defined, respectively.

    I don't know why only the a minimum is defined for the minimum positive pulse and only a maximum is defined for the positive pulse. I would expect the filter element to have similar filtering properties in both polarities.

    My experience is that 25MHz is about the highest square wave you can drive with no load. That is to say, a 40ns pulse is probably the smallest pulse in either direction that can be passed reliably.

    Best regards,

    Sean

  • 0 in reply to Sean Cashin
    TI__Genius 9555 points

    Hi Sean, 

    Thank you for response.

    Sean Cashin said:
    This specification pertains to the "minimum pulse width" that will pass through the gate driver. Both a minimum positive pulse and a minimum negative pulse are defined, respectively.

    Could you confirm what "negative pulse" and "positive pulse" mean? Do you mean they are for referring to INPUT signal on IN+/IN-? 

    Sean Cashin said:
    I don't know why only the a minimum is defined for the minimum positive pulse and only a maximum is defined for the positive pulse. I would expect the filter element to have similar filtering properties in both polarities.

    Datasheet says tPWmin1 and tPWmin2 parameters are separated by "No response at OUT where OUT <10% × VCC2" or "No response at OUT where OUT ≥90% × VCC2". Do you mean tPWminx spec is related to OUT voltage state?

    Regards,
    Ochi

  • 0 in reply to Yoshiki Ochi
    TI__Mastermind 23206 points

    Hi Ochi-san,

    By negative pulse, I mean output referred. That is, an input that creates a high output with a short low pulse, such as a 90% duty cycle PWM on IN+, and IN- held low. 

    By narrow positive pulse, I mean an input that creates an output with a short high pulse, such as a square wave with a 10% duty cycle: 

    By definition, negative vs. positive pulse depends on the initial output state. But the minimum pulse time of either polarity should be the same. They both equate to the same bandwidth.

    Best regards,

    Sean