TI-PMLK Buck Experiment Board: TPS54160 & LM3475 - Review

Table of contents

RoadTest: TI-PMLK Buck Experiment Board: TPS54160 & LM3475

Author: atiflz

Creation date:

Evaluation Type: Independent Products

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?:

What were the biggest problems encountered?:

Detailed Review:

Let's begin with what this board is, and what isn't. PMLK-BUCK board is an education material for college students. It is two different type of DC-DC converters on one board, with all the relevant test points exposed with metal loops for easy probe attachments. It is not really useful as a general purpose DC-DC converter as its voltages are fixed at 2.5 and 3.3 Volts and the board is much bigger than it needs to be.

 

Out of the box came the board, but it is not much of a use without its manual, found here.

 

The manual begins with circuit schematics, detailed description and bill of materials. Then it proceeds to a set of experiments. For each experiment, first there is theoretical summary, followed by "good to know" information. Then It shows test diagram. The diagrams are followed by detailed step by step setup instructions, and finally the actual test assignment. The instructions are concise and to the point. If you read all the steps carefully, you can do the experiments without confusion. The diagram for the first experiment looks like this:

Doesn't leave much room for confusion, although a bit crowded. I would have preferred simplified symbols for all the supplies and measurement equipment instead of photographs, but this is not really bad in any way.

 

 

The board itself has screw terminals for input and output. Several options (like capacitor values) are settable with jumpers, and the board comes with more jumpers than it will be needed. A simple detail, but well thought out. There are two circuits on one PCB, one with an LM3475, and one with TPS54160. The board feels sturdy and durable in my hand.

As seen in the photograph, the test points are conveniently broken out with metal loops, so both oscilloscope and voltmeter/amperemeter probes can be attached easily. Another cool feature is the large 0.01Ohm resistors on both circuits. It is R1 in the schematic below:

Since this is a low tolerance (1%) resistor, measuring the voltage over this resistor will give the current running over this resistor (divided by 100, obviously).

 

There are 6 experiments in total, followed by tests to check if we got the point. Although it is made for educational institutions,  things are laid out clear enough that it can used for self study, provided that we have all the needed measurement tools. Most experiments require two voltmeters and two amperemeters to measure all input and output characteristics, which might be a bit too many, but it is easy to work around. Overall it is a helpful tool to learn about internal workings of buck converters, and how different parameters affect internal workings of the device.

 

I was slightly disappointed by the fact that output voltages are not adjustable, and they are below 5 Volts. I would have loved to play with it by supplying power to my Arduino boards and servos and see effects of more complex loads. However, this is outside the scope of this kit. At roughly €50, it is an aptly priced learning tool.

Anonymous
  • I was interested in how Atilla got on with doing the exercises. This is his review, but he hasn't really said anything much about what he did and I was giving him a chance to say a bit more. It would be very useful feedback for TI to know if any of the experiments were more difficult than others and could, perhaps, be improved. The third experiment, on the transient response, looks really good to me - the discussion is probably the best condensed write-up of the material I've read to date - but I could imagine it all being a bit confusing if you've only done theory, don't have much practical experience of electronics, and are suddenly confronted with a whole lot of control system stuff and how it relates to the waveforms you're seeing. It's also the one that could be affected most by external conditions (ie what you use as the switched load), so it would be good to know how the reviewers did the test and, if they were improvising a load, how close they came to the waveforms given in the experiment.

  • It's advanced. Not suited to learn switch mode theory. At the right level to give practical insight to someone who knows the theory well.

    I'd say: targeted to EE students that just done the theory on EE level.

    It's assumed that you have that sound knowledge.

  • How did you find the exercises and the material provided to explain them? Were they pitched at the right sort of level for you? I've just had a look at the manual and some of it looks quite advanced to me (though very, very good - the 'discussion' pieces are worth a read even without having the board to experiment with).

  • DAB, that's part of one of the first labs for this kit. Measuring (and calculating based on formulas first) the ripple under different conditions.

    You're asked to use different witching frequencies, output capacity, load.

    This is covered extensively in the exercises.

  • Nice basic review.

     

    Did you check for output ripple?

     

    DAB