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Switcher Pro TPS54160 "what if" analysis bug report

Jorge12484
Prodigy 30 points

Other Parts Discussed in Thread: TPS54160

I found a bug on TPS54160 compensation network calculation.

For a same identical situation, Switcher Pro calculates and shows two differents results for Gain and Phase Margin.

For example, if you start a new advanced design for TPS54160 with this parameters:

Vin min = 8V

Vin max = 36V

Vout = 5V

Iout  max =1.5A

Iout min = 0.1mA

Vo ripple = 100mV

frequency : 600kHz

soft start: 100us

Gain Margin: 20

Phase Margin: 60

Transient Step Voltage: 5%

Swicher Pro will calculate:

C7=6.8p

C6=1200p

R3=44,2k

R1=10k

Without modifying anything, If you just take a look on "loop" tab, you will still seing a calculated Phase Margin of 60 Deg and a Gain Margin of -18dB.

But, if you just press "Calculate" button not changing any parameter, Switcher pro will calculate a new Gain Margin of -19db and a Phase Margin of 41 Deg with the same network components calculated before!!!

Does anyone knows wich result is reliable?

Best Regards,

Jorge

  • 0
    TI__Intellectual 2710 points

    Thanks for reporting this issue. We will investigate and fix this.

    The reason for different calculation in 'what if' page is becaulse the default conditions loaded in the form are not exactly same as the ones in the 'loop' tab. e.g. 'loop' tab is considering IOMin; while 'what if' is taking IOMax. Therefore, the graph changes.

    The results on the loop tab are correct.

    Thanks,

    Hetal Joshi

    Senior Developer and Project Manager

    Analog eLab Design Center

    HPA Design Tools

    Texas Instruments, Inc.

     

    TI makes no warranties and assumes no liability for applications assistance or customer product design. You are fully responsible for all design decisions and engineering with regard to your products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning your designs.

  • 0 in reply to Hetal
    Prodigy 30 points

    Thanks for answer.

    I think that this is not the real problem. If you go to "conditions" tab and place for example Iout equals to I out max or I out min, you will see that  the graphic changes on a different way.

    Also, I used the same value for both  IOMin and IOMax for just test if different values were loaded on form and the result was the same.

    I really need to design a customizedf TPS54160 based power supply for my company but unfortunetly Switcher Pro is not being reliable and trying to do by myself on MATLAB and I found that the equations shown on 27-28 page of its datasheet has missing parameters.

    I also designed a project based on TPS54362 in this case there is no differences on graphics.

    Thanks,

    Jorge