Archived Q&A from WEBENCH Office Hours held in conjunction with APEC 2013

Welcome to the WEBENCH Design Center Office Hours event. We are now "LIVE" and our experts are available to take your questions.

To post questions, hit “Reply” and post your questions in text format. We will be answering questions in the order they are received.

Hello,

I had a question. How can I create designs with TI's Automotive grade -Q1 parts?

Thanks,

surinders 

surinders,

If you are using a PSpice simulation, you can access the PSpice models from the Q1 part product folder. The models have included the reference design that was used to verify the corresponding commercial part. If the part is a Q1 only part, the reference design used was determined by the product line.

Britt

Hi Surinders,

To create a design using TI's Automotive grade Q1 parts, you can simply input your design requirements from the WEBENCH Designer launch panel at TI.com. Once WEBENCH loads, you can click the box titled "automotive devices" and that should filter out the devices to show you only automotive grade devices.

Please let us know if you have any more questions and require further assistance.

Regards,

Jazmine Livingston

WEBENCH Design Center

We are live on the APEC (Applied Power Electronics Conference) show floor and have several questions from customers regarding WEBENCH. They will be monitoring for your replies. Thanks!

Let's start with this one: 

How do I do a multiple output power system?

Hi Aimee,

From the WEBENCH Designer launch panel at TI.com, your customer can click on the FPGA/uP tab. From there, you can click on the button at the bottom that says "multiple loads" and enter your requirements on the page that follows.

Let us know if there are any more questions.

Regards,
Jazmine Livingston
WEBENCH Design Center

Jazmine,

Thanks.

I know that TI has a very good portfolio of automotive grade -Q1 LED drivers; do you support them in your tools too?

Regards,

surinders

From the APEC  floor..

Does WEBENCH allow me to look at the transient behavior of my power supply?

Hi Surinders,

Yes! We are currently supporting several of TI's automotive grade LED devices and are working on getting several more added quite soon.

Please go to the LED driver and check the Automotive box to select the -Q1 LED drivers.

For example, you please go to LED Power Designer, and put in the following input conditions.

Click "Next" and then select Automotive checkbox and you will see all the -Q1 automotive LED drivers filtered.

Regards,

Jazmine Livingston

WEBENCH Design Center

Hi Aimee,

Many devices are supported in WEBENCH Power Designer with online simulation for transient behavior.  If you enter design requirements from the TI.com home page WEBENCH panel, the list of solutions includes a symbol for online simulation (a red sine wave). After selecting one of these devices, and creating the design, click the "Sim" button on the top-of-page navigation bar.That will open the simulation utility. You can select the simulation type to run, usually including Startup, Load Transient, Line Transient, Steady State. 

Another one from the TI booth at the APEC show floor...

How many different file formats can I export my WEBENCH design into? 

Hi,

WEBENCH(R) Currently supports the below Design Export formats -

• Altium Designer
• Cadence OrCAD Capture CIS
• Mentor Graphics DxDesigner
• P-CAD
• Design Spark

Just Select the option and click export. To view the exported schematic, you need to have the related EDA Software on your machine.

Regards,

Pavani

WEBENCH(R) Applications Team

Another one from the TI booth at the APEC show floor....

Please explain if and how WEBENCH can tell me my design is stable?

Hi Aimee,

To find out if your design is stable, click on OpVals and looks at the “Phase Margin” and “Cross Freq”.

You can also click on Charts -> “View Other Charts”. Now check “Loop Response” option and hit “Save”. This will show the Bode plot.

WEBENCH also provide the ability to do Steady state and Transient simulations. Please click on the "Sim" option (if available).

Regards,

--Abhishek

When I do a Power Designer design, I see a large number of solutions. How can I quickly zero-in on my favorite part?

Hi Adam,

If the solution list for your specs is long you can filter by entering the device name of interest in the field highlighted in red as below.

Also, if you know the device name, you can directly go to device product page at www.ti.com/product/<device_name>  to launch designs using this device.

For ex, for TPS40170, www.ti.com/product/tps40170 is the product page. Every device that is supported in WEBENCH(R) has a design launch panel from the product page.

Regards,

Pavani

WEBENCH(R) Applications Team

Hello All,

Can we do an automotive-only power tree design for multiple loads?

Thank you

Hi Cameron,

WEBENCH Power Architect provides the ability to do automotive power tree design for multiple loads. Go to the WEBENCH Designer panel on TI home page and click on “Power Architect” option. Now Configure Your Power Sources and click on “Use Automotive Only” on the right.

Click “Submit Project Requirements”.

Regards,

--Abhishek

How can I get the listing of all the devices integrated in WEBENCH Designer?

Hi,

Visit webench.ti.com and click on "Power Designer Parts Listing" listed under "WEBENCH(R) Designer Tools or directly go to http://webench.ti.com/webench5/devices/ . You can choose based on topology or filter the results by WEBENCH(R) Tools enabled on them such as "Circuit Calculator","Thermal Sim", ""Simulation", and " Build It ". Or you can filter by the device design features such as asjustable frequency, soft start, Sync etc.  You can also choose device type from top dial options between Switchers, LDOs and Hotswaps.

Hope this helps.

Regards,

Pavani

WBENCH(R) Applications Team

More questions from this week's APEC (Applied Power Electronics Conference)...

The Optimizer Dial seems to have different functions on the Vizualizer page (where all parts that fit the solution are listed) and the Design page (once you click on “Open Design” and enter the product specific page). Can you explain how this works and what the different dial positions mean?

Hi Aimee,

Optimization knob is a tradeoff between footprint, cost and efficiency.

By changing the optimizer knob (dial) settings on the Visualizer, solutions using TI devices will be ranked differently depending on the lowest footprint (Knob 1), lowest cost (Knob 2) or highest efficiency (Knob 5). As you change the knob, you will see the solutions are displayed in different order.

For example, with default inputs and Knob setting 1

Note: The solution with lowest footprint shows first.

With Knob 5

Note:  Most efficiency solution shows up first.

So this is an excellent way to select the right device before creating and analyzing a design.

Now, when you pick a part from Visualizer and click “Open Design”, you will see the design details (single design view for that device). The purpose of optimization knob here is to pick the best set of circuit components for that design. So as you change the Knob from 1 to 5 you will see the components like inductor, capacitor etc. changing.

In summary, optimization knob on Visualizer helps you select the best solutions out of huge TI product portfolio; on the other hand optimization knob in the single design view helps you pick the best circuit components for that design. 

Regards,
LaRita Gwie
WEBENCH Design Center

More from the show floor...

What is the effect of using the temperature field in WEBENCH and how did we come to the default 30 degrees C?

What is the plan in supporting multi-phase Buck converters?

Hey Amiee,

The temperature field allows the user to create a WEBENCH design to emulate the user's environment.   For example, if the user wants to design a circuit at 100 degree C, WEBENCH takes into the account of the rise temperature from the room temperature (30 degree C) to 100 degree C and calculates the power dissipation accordingly. The solution will only offer devices that works at the 100 degree C. temperature.

The default 30 degree C is roughly room temperature.

When working with a design in WEBENCH® Power Designer, how can we change the output caps to a multiple number of caps?

Regarding support of multi-phase buck converters in WEBENCH Power Designer - There is support for the LM5119 and LM25119 dual-phase buck controllers. They can be used either as high-current buck converters or 2-output converters. The LM5119 & LM25119 product folder launch panels will generate the high-current application. If you wish to use the 2-output application, click the New button (on the top navigation bar from any WEBENCH design) and enter the requirements for the two outputs. See screenshot below for example.

How is the BOM cost calculated? 

Hi Aimee,

 Click “Select Alternate” in the BOM page to modify a specific component.

Next, select “Create Custom Component” at the bottom of the list of alternative devices.

Here you can add the custom specs for the new component and change the quantity. 

The BOM, OpVals, and graphs will be updated to reflect the custom component.

Please note that the other components won't be re-calculated.

Regards,
LaRita Gwie
WEBENCH Design Center

Hi Aimee,

All pricing is taken from a real-time (hourly) pricing feed from our distributors for non-TI parts and from TI’s web for TI parts. All pricing is based on 1K pricing provided apples-to-apples comparison of solutions.  You can optimize the design for your key concerns (smallest footprint, lowest cost, highest efficiency) by using the optimizer dial.

Regards,
LaRita Gwie
WEBENCH Design Center

WEBENCH is asking for the voltage and current at output(s). It asks for input voltage max and min. Why does it not ask for available input current from the user?

Regarding why the input requirements do  not include the input current budget - WEBENCH Power Designer creates designs offering a customizable blend of high efficiency, small footprint, and low BOM cost.  A design will always require at least as much input power as is being delivered to its load.  With higher efficiency solutions, the power loss is minimized so that the input power does not have to increase much above the load power.  Within each design, the Operating Values display the input current that will be required from the circuit power source.  The input current varies with input voltage, and you can change the input voltage used for the OpVal calculation there in the panel just above the Op Val table.

I am trying to use schematic export from WEBENCH. In the WEBENCH schematic I see only one component (e.g. capacitor).  But in the exported schematics I see multiple capacitors. Can you explain what is going on, please?

Does WEBENCH support power management units (PMU)? If so, can you tell me how to design with them?

Hi Aimee,

In the WEBENCH schematic, Qty =2 implies 2 capacitors of the same value in parallel.

In the exported Altium schematic, capacitors are unstacked and all of them are displayed.

Regards,
LaRita Gwie
WEBENCH Design Center

Hi Aimee,

We have recently enhanced WEBENCH Power Designer with the addition of PMU’s. To create a WEBENCH design for a particular PMU, go to the product folder and enter your design criteria in the WEBENCH panel.  For example, you can go to the product folder for LP3907 (http://www.ti.com/product/lp3907) where you will see the WEBENCH panel on the right.

Once you open the design, you will see an introductory message on PMUs and how to use them in WEBENCH:

As an aside, this is an I2C controlled PMU so you can set the output voltage Hex codes in the design to change Vout.

Regards,
LaRita Gwie
WEBENCH Design Center

Thanks to everyone who participated in this event!

We are now marking this thread "CLOSED". Please post new questions as a new thread in any of the WEBENCH forums as applicable.

Links to all WEBENCH related forums are at:

http://e2e.ti.com/support/development_tools/webench_design_center/default.aspx

I'm designing a SEPIC supply using the TPS40210.  I'd like to use Webench to analyze the circuit but I cannot find a way to force it to use that part.  I put in my input and output voltage range, 10-30 volts in and 24 volts out, and it suggest various circuits but non of them use the TPS40210.  Can I force it to use a particular part and topology?

thanks,

Rich

Richard,

At this point, TPS40210 has been integrated in WEBENCH in the boost configuration only. Hence, you cannot use WEBENCH for this device in SEPIC topology. There are other devices integrated with SEPIC topology which you can use, though.

Thanks.

Richard,

As Surinder mentioned, SEPIC operation has not been integrated for the TPS40210 yet. However, there is a TI PowerLab Reference Design solution that may suit your needs.

I went to http://www.ti.com/powerlab and searched for your input and output voltage requirements. Check out PMP7073.

-Kris

Does web bench support parallel FETS? How do I tell it to place FETS in parallel?

Marty

Hi Marty and Larita,

Actually, you can add parallel FET(s) into your default circuit by using the WEBENCH Schematic Editor. However, the default FET selection routin has been implemented to optimize the cost, efficiency and footprint of the BOM. By manually adding parallel FET(s), one may deviate from the sweet spot proposed by WEBENCH. Below, I am showing an example how one can integrate a parallel FET into default circuit.

Regards,

--Hadi