Webench error Circuit Calculator can't create design

Kevin Ferenc

Other Parts Discussed in Thread: LM3409HV, SWITCHERPRO

I would like to use an LM3409HV to drive a single CREE MT-G2. Vf=36V, Iled=350mA, Vin,min=46V, Vin,max=50V. The LM3409HV is a bit over qualified for the design, but we stock it and it has excellent dimming capability.

Unfortunately I cannot get Webench to create a solution. The LM3409HV is in the exclusion list, with a comment of "Circuit Calculator can't create design".

Is there a way to get around this to see a potential design?

I can use the Excel calculator, but I would really like to use Webench as a check.

Thanks.

over 9 years ago

0 Howard Chen-WEBENCH Design Center over 9 years ago

TI__Expert 6365 points

Hi Kevin,

Thank you for letting us know that the LM3409HV was not working on WEBENCH. I have made the correction and it should be available by tomorrow.

0 Kevin Ferenc over 9 years ago

Prodigy 70 points

Hello,

I have tried this again and it still doesn’t seem work. It still excludes the LM3409HV.

Kevin

From: Howard Chen-WEBENCH Design Center [mailto:bounce-1879878@mail.e2e.ti.com]
Sent: Monday, October 27, 2014 4:54 PM
To: switcherpro@mail.e2e.ti.com
Subject: RE: [Power and Lighting Tools Forum] Webench error Circuit Calculator can't create design

Hi Kevin,

Thank you for letting us know that the LM3409HV was not working on WEBENCH. I have made the correction and it should be available by tomorrow.

0 Kevin Ferenc over 9 years ago in reply to Howard Chen-WEBENCH Design Center

Prodigy 70 points

I have tried the design again and the LM3409HV is still excluded for the reason "Circuit Calculator can't create design".

Kevin

0 Kevin Ferenc over 9 years ago in reply to Howard Chen-WEBENCH Design Center

Prodigy 70 points

Can someone please tell me if this fix is still in the works? As of 10/30 it is still inoperable.

Kevin

0 Howard Chen-WEBENCH Design Center over 9 years ago in reply to Kevin Ferenc

TI__Expert 6365 points

Hi Kevin,

I'm very very sorry. The updates did not get applied to the production server as I expected but it's scheduled for tomorrow. I have created your design on our development server and it's working well. I have included the design report here. Let me know what other conditions you would like see and I can run them for you.

Again, I apologize for the delay.

2210.LM3409HV_45-50Vin_36Vout_350mA-ILED.pdf

0 Kevin Ferenc over 9 years ago in reply to Howard Chen-WEBENCH Design Center

Prodigy 70 points

Hello. Would you please run a solution with a switching frequency between 400kHz and 500kHz?

Thanks,

Kevin

0 Kevin Ferenc over 9 years ago in reply to Kevin Ferenc

Prodigy 70 points

Webench has been updated to support the LM3409HV solution. Thanks. But when I try to set the switching frequency to 350kHz and the LED current ripple to 10%, the Optimizer will not run. Please advise.

0 Howard Chen-WEBENCH Design Center over 9 years ago in reply to Kevin Ferenc

TI__Expert 6365 points

Hi Kevin,

The particular feature you were looking at is broken. I’ll take a look why it won’t create the design at higher frequency and with the ripple feature.

The maximum frequency is restricted by the combination of the IC power and FET power and the theta JA of the packages. Per your design specifications, the maximum frequency was limited to 352kHz and it won’t allow the user to run at higher frequency (400 or 500kHz). One option, you can test is creating a new design with 0 degree ambient temp, it should raise the max. frequency some.

I apologize for the inconvenience and I’ll try get the fix done quickly but most likely you won’t see an update until Thursday.

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Webench error Circuit Calculator can't create design