• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 64 subscribers
  • Views 101 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LM5148: Inquiry about LM5148 Slope compensation value

Jamie LEE
Prodigy 360 points
Part Number: LM5148

Tool/software:

Hi experts,

I have a just one question about Slope compensation.

In datasheet, there are only two value about slope compensation value.

SLOPE1

Internal slope compensation1

RRT = 9.52kΩ

600mV/us

SLOPE2

Internal slope compensation2

RRT = 97.6kΩ

50mV/us

I'd like to know what about RRT = 75.6kohm? (Fsw=280kHz)

There is any formula to calculate slope compensation value? or Is the RRT linear with Slope ramp?

Thank you!

Best Regards,

Jamie LEE

  • +1
    TI__Genius 11695 points

    Hi Jamie,

    Please see comment from the datasheet: " For design simplification, the LM5148 has an internal slope compensation ramp proportional to the switching frequency that is added to the current sense signal to damp any tendency toward subharmonic oscillation." -

    So yes, in simple words - the internal slope value will be proportional to fsw (which in turn is set by the Rrt resistor). Rrt is related to fsw by equation 4 in the datasheet - that should give you the correlation between Rrt and internal slope compensation. You can linearly interpolate the data to get the slope comp value at the fsw that you choose. 

    Thanks,

    Best Regards,

    Taru