Voltlog #280 – TPS62840 olmBoard Ultra Low Power Step Down Converter

Welcome to a new Voltlog, in this video we are taking a look at the TPS62840 ultra low power step down converter from Texas Instruments. It’s basically a buck converter with an input voltage of 1.8-6.5V, 750mA output current, with a quiescent current of just 60nA and active current of just 120nA. It also features very good efficiency at light loads of just 1uA it can offer 80 percent efficiency.

Other features include 16 selectable output voltages through an external resistor and a stop pin which when activated will completely stop any switching to eliminate any switching noise for a short moment, allowing you to take for example an ultra low noise measurement during that time. During that take power will be sourced from the output capacitors. So it looks like this is a pretty interesting dc-dc converter, with really nice features and it’s optimized for ultra low power devices.

Voltlog #272 – Car Relay GPS Tracker Setup CJ720

In this video we’ll take a look at the CJ720 car relay gps tracker, I’ll show you how to setup the tracker and how to get position information. I will show you what kind of commands this tracker accepts and I will also do a teardown towards the end.

For information on how to setup your own GPS Tracking server, running on a raspberry pi, using open source software, checkout Voltlog #274.

Voltlog #266 – How To Check If Your Raspberry Pi 4 Is Throttling CPU

Welcome to a new Voltlog, today my raspberry pi 4 is again in the spotlight because I want to show you the different scenarios where the board could be throttling down the CPU frequency and how you can identify those. Because it might be a case where your raspberry pi is running slow on a particular task and you don’t know why because there is no built-in mechanism to let you know when the board is throttling down. There are logs which you can check but let’s be honest, few people actually check the logs for something like this.

Throttling of the cpu frequency occurs for good reasons, to protect the board or the cpu from overheating or to prevent any errors from occurring in the case of an under-voltage scenario which may lead to data loss or corruption. Luckily there is a way to check if your system is under one of these conditions, you can run this command on your raspberry pi.

Voltlog #264 – Passive Heatsink Cooling For The Raspberry Pi 4

Welcome to a new Voltlog, here is my raspberry pi 4 which I got a few months ago when they released it and if you have one you might have noticed it gets quite hot especially when it has to do some processing. This newer processor, will get hot quick and the board alone cannot cope with all of this heat so what does it do? Well when the CPU temperature reaches 80 degrees Celsius it will start throttling down the CPU as a way of protecting itself from overheating and this will result in a loss of performance.

The Raspberry Pi 4 has a 1.5GHz quad-core 64-bit Arm Cortex-A72 CPU, that’s roughly three times the performance of the raspberry pi 3 cpu. That inevitably generates more heat. In the original plastic case just sitting idle, connected to a network, doing pretty much nothing, the raspberry pi4 when compared to a raspberry pi3 runs about 12 degrees hotter.

Voltlog #260 – How do you test usb to serial converters? (CP2103 vs CH340E vs FT232RL)

Welcome to a new Voltlog, today we’re comparing a few different serial to usb adapters and the discussion started ever since I showed the CH340E breakout board I designed in voltlog #249. People wanted to know if this CH340E affordable chip would perform similar to the well known FTDI or Silicon labs chips, and I’m thinking at high throughput and reliability here, the kind of application where you are sending lots of data, fast and you need it to be transferred reliably.

So today I’m going to compare the CH340E with a CP2103, and the FT232RL. I wasn’t sure what measurements to take and how to test these but I devised 2 testing methods.

Voltlog #246 – What if we install a heatsink on the TPS61088 boost module?

In the previous video where I took a closer look at the TPS61088, I did some measurements of the output noise but I also ran the module up to the maximum specified output power of 12V 2A. It was to be expected that the losses would turn into heat and just the small size of the board would not be enough to dissipate all that heat safely so the boost chip reached a toasty 150 degrees Celsius and inevitably went into thermal protection.

There were two questions that people mainly left in the comments of that video. First people were curious if this module would behave differently if a heatsink was installed and also some people thought about using this module in a fixed configuration, because if you remember there is a chip on this module that will switch the output voltage based on quick charge spec, depending on what the load is requesting through that protocol but people might just want a simple fixed output. To this I would add a third question of my own, what is the real efficiency figure of this module, at the maximum output. 

Voltlog #245 – TPS61088 Boost Module Test (with QC3.0)

The real limitation for this small module to output the claimed 24W for longer periods of time is temperature. There is not enough thermal dissipation happening with this small pcb. Having a bigger pcb with more copper layers would help and it would probably allow this module to output continuously and prevent the TI controller chip from going into thermal overload. Even so I was impressed that running it into thermal protection several times did not do any damage the chip recovered on it’s own each time and no magic smoke escaped during these tests.

So all of this considered, this is probably one of the best dc-dc boost converter modules I got from China so far and I would recommend getting one of these if the specs meet your needs.

Voltlog #234 – The Problems I Found With The KSGER T12 Soldering Station

In a previous Voltlog I reviewed this KSGER T12 soldering station, it was the first station I got my hands on from this manufacturer, it’s version 2.1S and I was pleasantly surprised by the features it has. If you haven’t seen that video I will link it on screen right now. Since then I’ve been using it as my main soldering station and I’ve been pretty happy with how it works but some of my viewers who have been using these for longer have pointed out a few things I missed in the video so this will be a quick update video to show the things I’ve missed previously.

Voltlog #232 – My New Prefered T12 Soldering Station KSGER V2.1S

Out of the three T12 stations that I have, this is now my favorite and will be the one I use daily. I’m not sure if the performance is higher or similar to the other I have, I’ll probably do a separate video to compare them but it’s just the user interface, the menu options, the nice handle that make me wanna use this instead of the others. Yes it has a few disadvantages regarding this handle, it does get warm and it doesn’t really fit that well with a regular stand but I can go past those disadvantages for how nice this station is. If you’re looking for a T12 station this is definitely the one to get.

I also did a second video where I showed the problems I found with this soldering station and if they can be fixed by the user or not.


Voltlog #227 – Identifying Pure Nickel Strip vs Nickel Plated Steel

Welcome to a new Voltlog, if you’re a frequent viewer of my videos you’ve no doubt seen me build this spot welding machine that I use occasionally for building battery packs for my RC planes. I use this machines to create nice welding spots between nickel strips and the battery contacts. My battery packs do not exceed 20A passing through and that’s only in short bursts but there are people building higher current battery packs and so it’s important for them to be using pure nickel strips instead of nickel plated steel strips for making the links.