• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 39 subscribers
  • Views 488 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.

Output cap calculation failure in V3.4 for TPS40210

maxthestork
Intellectual 390 points
Other Parts Discussed in Thread: TPS40210

Hi All,

 I am not able to get any designs to work with a TPS40210.  I am after a design with the following inputs

Vin min 11

Vin max 14

Vout 30V

I out 2.5A

 

The error I get isshown below in itailcs.  I can't understand the current rating >= 35A.  What is this current?  The RMS current throught the inductor is around 7 - 8 A .  Is this a bug or is it correctly highlighting an impossible design.

On a related note.  Should the ESR requirement for the output cap as described in the datasheet be seen as a target or a maximum value? 

 

Thanks for any feedback

Peter

 

Calculated Specs for Cap are:  Value = 680uF, Qty = 1, ESR = 55.8mΩ
Type = CapCeramic,Voltage >= 35V,Current Rating >= 35A


Calculated Specs for Cap are:  Value = 390uF, Qty = 2, ESR = 111.6mΩ
Type = CapCeramic,Voltage >= 35V,Current Rating >= 35A


Calculated Specs for Cap are:  Value = 270uF, Qty = 3, ESR = 167.4mΩ
Type = CapCeramic,Voltage >= 35V,Current Rating >= 35A


Calculated Specs for Cap are:  Value = 180uF, Qty = 4, ESR = 223.2mΩ
Type = CapCeramic,Voltage >= 35V,Current Rating >= 35A


Calculated Specs for Cap are:  Value = 150uF, Qty = 5, ESR = 279mΩ
Type = CapCeramic,Voltage >= 35V,Current Rating >= 35A


Calculated Specs for Cap are:  Value = 120uF, Qty = 6, ESR = 334.8mΩ
Type = CapCeramic,Voltage >= 35V,Current Rating >= 35A


Calculated Specs for Cap are:  Value = 100uF, Qty = 7, ESR = 390.6mΩ
Type = CapCeramic,Voltage >= 35V,Current Rating >= 35A


Calculated Specs for Cap are:  Value = 82uF, Qty = 8, ESR = 446.4mΩ
Type = CapCeramic,Voltage >= 35V,Current Rating >= 35A

Design Halted.


 

  • 0
    TI__Intellectual 2710 points

    Hello Peter,

    This is the same issue as you have reported in another post. We have found the issue and fixed it in the program. We will release it in our new version v3.5 next month.

    Thanks,

    Hetal.

  • 0 in reply to Hetal
    Prodigy 10 points

    Hello,

    I tried to simulate the same:

     

    Vin min 11

    Vin max 14

    Vout 30V

    I out 2.5A

     

    The software version is 

     

    SwitcherPro Desktop

     

    Version 3.7.8.23120

    Built on 2010-05-20 02:50 PM

    Copyright © 2010, Texas Instruments, Inc

    Database Version 211

     

    I got error as follows:

     

     

    Error building the design. The Designer could not successfully build an  warning  free design with this device and these inputs.

     

    Warning: Gain margin for this design, 9dB, is lower than the minimum 10dB. Low Gain Margin Warning!

     

    Warning:  calculated wattage is greater than rated wattage for this device.

     

    Design Halted.

     

     

     

     

     

    ************Detailed Design Event Trace************

     

     

     

    Design test Started at 6/1/2010, 2:36:07 PM.

     

     

    TPS40210 Selected for this Design.

     

     

    Starting Design for Channel 0...

     

     

     

    Basic Design Inputs:

     

    Vout = 30.00

     

    Iout = 2.500

     

    VinMin = 11.00

     

    VinMax = 14.00

     

     

     

    Other Design Inputs:

     

    VoRipple = 0.600

     

    VinRipple = 0.280

     

    Phase Margin Min = 45.0

     

    Gain Margin Min = 10.0

     

     

     

    Successfully Precalculated Basic Design Information.

    DCM Mode = False

    DutyMin = 0.55

    DutyMax = 0.66

    FreqCrossOverTarget = 100 KHz

    Inductor Peak Peak Current = 9.66A

    IoutMin = 4.83A

    FreqSwitchingMin = 630 KHz

     

     

    Calculated Specs for Inductor are:

    Inductor Value = 5.6uH, RMS Current Rating = 8.05A

     

    1 Inductors found in the database.

    IHLP-5050CE-01 5.6uH, value = 5.6uH. DCR = 18mΩ.

    IHLP-5050CE-01 5.6uH selected.

     

    Update Basic Design Calculations Succeeded.

     

     

    Calculated Specs for Cap are:  Value = 47uF, Qty = 1, ESR = 94.3mΩ

    Type = CapCeramic,Voltage >= 30.2V,Current Rating >= 30.2A

     

     

    No Caps found for with:  Value >= 47uF, Qty = 1, ESR <= 94.3mΩ

    Type = CapCeramic,Voltage >= 35V,Current Rating >= 35A

     

     

    Calculated Specs for Cap are:  Value = 27uF, Qty = 2, ESR = 188.6mΩ

    Type = CapCeramic,Voltage >= 30.2V,Current Rating >= 30.2A

     

     

    No Caps found for with:  Value >= 27uF, Qty = 2, ESR <= 188.6mΩ

    Type = CapCeramic,Voltage >= 35V,Current Rating >= 35A

     

     

    Calculated Specs for Cap are:  Value = 18uF, Qty = 3, ESR = 282.8mΩ

    Type = CapCeramic,Voltage >= 30.2V,Current Rating >= 30.2A

     

     

    No Caps found for with:  Value >= 18uF, Qty = 3, ESR <= 282.8mΩ

    Type = CapCeramic,Voltage >= 35V,Current Rating >= 35A

     

     

    Calculated Specs for Cap are:  Value = 12uF, Qty = 4, ESR = 377.1mΩ

    Type = CapCeramic,Voltage >= 30.2V,Current Rating >= 30.2A

     

     

    No Caps found for with:  Value >= 12uF, Qty = 4, ESR <= 377.1mΩ

    Type = CapCeramic,Voltage >= 35V,Current Rating >= 35A

     

     

    Calculated Specs for Cap are:  Value = 10uF, Qty = 5, ESR = 471.4mΩ

    Type = CapCeramic,Voltage >= 30.2V,Current Rating >= 30.2A

     

    3 Capacitors found in the database.

    GRM55DR61H106KA01K, value = 10uF, ESR = 8mΩ

    C5750X5R1H106M, value = 10uF, ESR = 9.6mΩ

    ECJ4YF1Y106Z, value = 10uF, ESR = 10mΩ

    GRM55DR61H106KA01K selected.

     

     

    No High Freq Output Cap Needed.

     

     

    High Frequency Output Capacitor has been left open.

     

     

    MosFET specifications calculated successfully.

     

     

    MosFET Selection For Role = MosFETHighSide was successful.

    PN: Si4470EY

    Qty: 1

    RatedVoltage: 60V

    Current Rating(individual): 12.7A

    GateCharge(individual): 46nC

    Area(individual): 32.000mm²

     

     

    Calculated Spec For Rectifier Diode. 

    BreakDown Voltage >= 30.2V.

    ForwardCurrentRating >= 2.5A

    Type=Schottky.

     

    10 Diodes Found,

    sorted by Efficiency.

    PN MBRA340 Selected.

     

    Update Basic Design Calculations Succeeded.

     

     

    Bulk Input Capacitor has been left open.

     

     

    Calculated Spec For HF Input Capacitor(s).

    Qty= 1, Value= 10uF, ESR= 5mΩ and Type=CapCeramic

     

    1 Capacitors found in the database.

    GRM31CR61E106KA12L selected.

     

    Timing Resistor is selected.

     

    Resistor for ResistorTiming role Selected.

     

    No Sync Resistor Needed.

     

    Resistor for ResistorSYNC role not needed.

     

    No Current Limit Resistor Needed.

     

    Resistor for ResistorCurrentLimit role not needed.

     

    Snubber RC Circuit specified.

     

    Successfully selected RC circuit componenets.

     

    Slow Start Cap Value Calculated.

     

    Slow Start Componenets Selected.

    Capacitor for CapacitorSlowStart role Selected.

    Resistor for ResistorSlowStart role left empty.

     

    No UVLO Components Needed.

     

    UVLO Componenets Selected.

    Resistor for ResistorUVLOTopDivider role not needed.

    Resistor for ResistorUVLOBotDivider role not needed.

     

    External current Sense Resistor spec calculated.

     

    Resistor for ResistorCurrentSense role Selected.

     

     

    Compensation Calculation Complete.

     

    Compensation Components Selection Started.

    Compensation Components Selected.

     

     

    Decouple Routine Started.

    Capacitor ByPass  Selected.

    VDD Cap Selected.

    Gate Res Selected.

    Current Sense Filter Res Selected.

    Current Sense Capacitor is Selected.

    Standard Parts Selection Complete.

     

    Update Basic Design Calculations Succeeded.

     

    Error building the design. The Designer could not successfully build an  warning  free design with this device and these inputs.

     

    Warning: Gain margin for this design, 9dB, is lower than the minimum 10dB. Low Gain Margin Warning!

     

    Warning:  calculated wattage is greater than rated wattage for this device.

     

    Design Halted.

     

    Could you check what the problem is?

     

    Thanks