I am a Road Tester of the TI-PMLK Buck Experiment Board: TPS54160 & LM3475.
It's an educational kit - board and book - to learn buck converter theory and practice.
I applied for the Road Test to check the educational value of the kit. The focus in this blog series will be on the Lab Manual and exercises.
How Educational Is This?
Let's start with the conclusion. This is a great lab kit when you're learning witch-mode power supplies.
It lets you experiment with good designs and stable conditions.
But it also allows you to validate non-optimal situations such as oscillation and instability,
The two different Buck configuration on the board allow to review fully integrated designs (the step-down DC-DC converter - based on a control loop - on the lower part of the PCB) and
circuits with external power transistors (Hysteretic PFET Buck controller).
You can do several of the exercises on any of the two if you like. But the different nature of the two controllers invite you to do a comparison.
And you can probe the gate of the power transistor in the upper board.
This kit isn't (and is not intended to be) a tutorial. The expectation is that you understand the mechanism of Buck converters.
That said, everywhere in the book you get pointers to the mechanisms at play for the experiment you're doing. Short theory review and formulas are provided.
The book also expects some maturity from the experimenter.
Although not necessary to complete the labs, you're challenged to review the datasheets of components at certain times.
How Practical Is This?
That's the biggest asset of this book in my view.
It requires theoretical knowledge. Doing the exercises without understanding the circuits is pointless here.
There's a lot at play in switch-mode converters that someone has to learn you.
A basic intro in the subject will not be enough. I advise the excellent Introduction to Power Electronics from the University of Colorado on Coursera.
I had a conversation on the subject with my friend ipv1 here recently. We have different views on this.
The Buck experiment board allows you to try out almost everything that's discussed in your theory class.
You can probe the behaviour in steady state, measure efficiency and loss (often at component level).
You can put the circuits in an unstable mode and see what happens, check ripple at different switching frequencies.
There are test points for all the interesting signals. There's much more that you can measure outside of the lab experiments.
The experiments range from the basic behaviour of the Buck circuit to some more subtle things that happen within the circuit.
Efficiency and loss, ripple, switching frequency, transient response, inductor limitations and saturation.
No. There isn't an experiment, practice or explanation that's specific to TI components.
There isn't vendor bias in the whole explanation. It's obviously a marketing vehicle. Anything on the board that's could be sourced from TI is a TI component.
And the names of the two regulators are all over the place. I don't mind. It doesn't take away at all from the kit's educational value.
You can use the practices of this lab with parts of any other vendor, or with a Buck evaluation board from another vendor.
|1a: 1st Experiment Set-up|
|1b: 1st Experiment Lab Setup|
|1c: 1st Experiment Measure|
|2: Educational Value|