UCC256404: UCC256404

Hi Sam,

1. I used WEBENCH^® Designer UCC28056 it will give me schematic and BOM ,shall i use WEBENCH Design or PMP9531 Ref design? *Webench is a good tool, but it does not always provide the best options. For example when I put in your requirements, I get the UCC28056+UCC28600 recommendation. But if I just use the output of a PFC stage, I several more options including the attached. Note: When you try this webench will provide recommendations using the UCC25630x series but we now how the UCC25640x series which is an improved version. 

2. UCC28056BEVM-296 Evaluation Module on page 17 has a  schematic which one is better for my application? 1 or 2 *This EVM was designed to support up to 165-W. For higher power, you would need to modify it. 

3 I also used UCC28056X Design calculator it has schematic which one is better  * The calculator will help you optimize your design. 

3. Do you have MATCAD PFC? * Unfortunately no. We just have Simplis models and the design calculators. 

4. I am using  LLC UCC256404  controller with designed to pair with a PFC controller.  I used WEBENCH^® Designer  it will give me schematic and BOM ,shall  i use WEBENCH Design or PMP9531 Ref design? * It is really up to you. The UCC25640x series should be a simplier design as it integrates the gate drivers and more. 

5 UCC25640EVM-020 Evaluation Module page 8,9, has a schematic shall I used this one or PMP9531 *PMP9531 is closer to your power level. The UCC25640EVM-020 was only designed to support up to 180-W

6 I saw  PMP31179 is it good for my application? * This is a good find. I was not sure if you wanted to go with an interleaved PFC. While a little more complex, this will have lower ripple currents and better efficiency.

Is there Mathcad for UCC28056 * Unfortunately no. We just have Simplis models and the design calculators. 

How do i determine the Transformer ratio and calculation? * The datasheet has a step-by-step procedure, but the design calculator is easier to use. 

How do I adjust the  32VDC out on PMP9531 design? The UCC28600 design calculator can help you do this.WBDesign51.pdf

Hi Sam,

1. On PMP9531 Page 1 do  I have to change anything? *No. You can use the UCC28051. The UCC28056 is a newer version.

2. page 2 it shows 28V@12.5A I used your UCC28600 design calculator it don't tell me parts values to change? PM9531 design used UCC25600D

  I need a help with how to, use the calculator change the parts values for PM9531

   Your web design shows 256403. There is another calculator UCC25640X can use this One? * The calculator is to help you make your own schematic. The excel calculator shows the components you need to select to support your input/output voltage and power requirements. 

4. I still don't understand transformer design * Normally, you share the turns ratio an other parameters from the Excel calculator with your preferred transformer manufacturer and they help to optimize your design. 

I hope this helps.

Hi Sam,

For your questions:

1. The design calculator shows the generic values to use. PMP9531 uses bipolar transistors to make a stronger gate drive. I would follow PMP9531 as a baseline.

2. I am not understanding this question. T1 is the same part on the BOM and schematic of PMP9531.

I hope this answers your question.

HI Sam,

Mani is suggesting the UCC256404 as it integrates the gate drivers and other functionality which can help to simplify the design. 

With respect to the right PFC it is up to your application needs the UCC28056 will be a lower cost and simpler design. the UCC28064A will cost a bit more but will have better efficiency and ripple. 

We only have the UCC28064A available. Are you asking for the UCC28056B? Here are the differences between the different UCC28056 options

If you are connecting the EVM to the output of a PFC, there is no need for a diode bridge. 

I hope this helps.

Hi Sam,

Sam Abeysekera said:

Do i have to change the values On the spread sheet Raw # 103 and 104

You need to update these values form the Gain curve. Please see the comments next to these rows.

Sam Abeysekera said:

Raw # 32,33,34 are input to the LLC from PF # UCC28056?

Yes, Thats correct.

Regards

Manikanta P

Hi Sam,

Please see the modified design calculator.

Regards

Manikanta PSAM_3463.UCC25640x Design Calculator Rev4.0 (1).xlsx

Hi Sam,

Please see the below picture for bias winding number of turns. These turns are determined assuming the bias winding voltage is 15V. Also, the current taken by the controller is very small compared to output current. You can assume a current rating of 0.1A for the bias winding.

Regards

Manikanta P

Hi Mani

Thanks

Sam

Hi Sam,

You can get Simplis here: https://www.simplistechnologies.com/ unfortunately, it is not free.

We do not have a released Simplis model of the UCC28051, but we do for the UCC28056.

What you will like about Simplis once you get used to it is that you will find it is a much faster simulator that is well suited for simulating a full system-level schematic. 

Regards,

Hi Sam,

Yes. This is why Simplis is a popular simulator.

HI Sam,

I am sorry I misunderstood your question. We do not have a combined UCC256404 and UCC28056B Simplis model. You would need to import each model into Simplis and connect them together as you would in your application.

Hi JHCK

Thanks

Sam

HI Sam,

Here is the feedback circuit that you could use for your application.

Since TLVH431 max cathode voltage is only 18V which is more than your output voltage, you need to use zeners as shown in above picture.

For all other component values in the above schematic, you can use same as EVM schematic (PFCLLCSREVM-034 User Guide (ti.com)) values.

Audio susceptibility plot give the bode for output to input voltage transfer function.

Regards

Manikanta P

Hi Sam,

The control methodology of the UCC25640x is similar to the current control of a PWM converter.

You can use this controller for any type of control whether it's a output current or output voltage which depends on the application.

The EVMs schematics controls the output voltage. 

We do have reference designs that controls the output current (https://www.ti.com/tool/PMP40766 ) which is required for battery charging and LED driver applications.

Since LLC resonant converter uses magnetizing inductance (Lm) and resonant inductor (Lr) and resonant capacitor (Cr) as part of the resonant tank, it is called as LLC converter. 

Regards

Manikanta P

Hi Sam,

Could you please create a different thread for parts not related to the UCC25640x. The engineer who supports PFCs should be able to help you with this.

Regards

Manikanta P

Hi Sam,

Yes, it can be used in military application.

Regards

Manikanta P