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 #248 – Atorch Q7 USB Meter/Load With QI Wireless Charging

So this load is built with 3 active pcb’s as well as a fourth passive one as a front panel. They are joined with these brass standoffs and I think the standoffs act as circuit paths as well because I see no wires between the different levels. In order to get the alignment right during assembly the designer of these pcbs, made these corners rounded while these ones are diagonally cut and you can see these features along an entire side. This is a neat solution overall because it saves cost and as long as the screws are tight these should provide adequate connection.

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 #121 – InTheMail

This video starts with a rant about how bad the postal system is around here(Romania).

Here is a list with links to all the items shown in this video:

Voltlog #120 – Mini DC Power Supply Review

So I guess a gadget like this is worth 10$ because you could replace that linear breadboard power supply with a more efficient one, which will give you voltage and current display as well as adjustable output.

Here are some images I took during the teardown of the mini power supply:








Checkout this power supply from the links below:

60W Electronic Dummy Load Battery Tester:

Voltlog #119 – NEW 150W Dummy Load Review

Today we are taking a look at yet another electronic load. I found this one on Aliexpress, I think it’s a rather new model so let’s see what it can do.

Here are links to the 150W and the 180W version of this dummy load:

Voltlog #82 – DIY Adjustable Analog DC Electronic Load

In this episode I am building an analog adjustable dc load with parts easily obtainable from ebay and banggood. The advantage of such a dc load is that you can understand how it works, modify or repair it if necessary far easier than you would with a digital one. I was able to push mine up to 60W dissipation, but it is recommend to stay under 50W to protect the mosfet.

Here is a list with links to the parts used in this project:

Voltlog #66 – Cheap NiMH Rechargeable Battery Testing

If you were following my InTheMail videos you probably seen these green rechargeable batteries that I got from ebay quite cheap, I think they were like 50 cents a piece. I got 4 pcs in AA size and 4 pieces in AAA size and little did I know about how crappy these could be.