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LM5030: questions

Ivy Jin
Intellectual 2690 points
Part Number: LM5030

Hi team,

My customer uses LM5030 in their project(Vin=48V, Vout=210V/1A), could you please help check below questions?

1. What is the operating mode of the LM5030 at light load (or no load), is it a hiccup mode?

2. The power range recommended on the datasheet is 15W to 150W, is there a risk if the power is 210W?

3.SNVA548 this document recommends frequencies from 100K to 1M. Can they set the frequencies to 65KHz?

4. Could you please help review the feedback loop's schematic?

Appreciate for your help!

Regards,

Ivy

  • 0
    TI__Mastermind 24105 points

    Ivy,

    1. What is the operating mode of the LM5030 at light load (or no load), is it a hiccup mode?

    • You may see pulse skipping at light/no load but not hiccup mode as it is defined in the data sheet during overload operation. 

    2. The power range recommended on the datasheet is 15W to 150W, is there a risk if the power is 210W?

    • No risk, as long as your power stage can handle the voltages and currents expected. You can verify your power stage using TI Power Stage Designer. The recommendation of 15W<P<150W could be based on theLM5030 internal gate drive capability. For example, at 210W, you may requires lower RDS(on) MOSFETs that have higher gate charge where 1.5A may not be enough. If this is the case, you may consider an external gate driver.

    3.SNVA548 this document recommends frequencies from 100K to 1M. Can they set the frequencies to 65KHz?

    • Not sure since the minimum recommended is 100 kHz. 65 kHz operation would require RT=83.6 kΩ  - build it and see?

    4. Could you please help review the feedback loop's schematic?

    • All the placeholders look correct but I'm not sure why the additional pole/zero is needed (circled in red). Push-pull operating in peak current mode control can be compensated with a standard type 2 compensator which you have (circled in blue) and this is all that should be required. I suppose you can DNI the extra circuit in red if it is not needed. TI Power Stage Designer also has a control loop compensation tool that can help you model your control loop.

    Regards,

    Steve M