Some time back we ran a post on those cheap USB soldering irons which appeared to be surprisingly capable considering they were really under powered, literally. But USB Type-C is slated to change that. Although it has been around for a while, we are only now beginning to see USB-C capable devices and chargers gain traction. USB-C chargers featuring the USB-PD option (for power delivery) can act as high power sources allowing fast charging of laptops, phones and other devices capable of negotiating the higher currents and voltages it is capable of sourcing. [Julien Goodwin] shows us how he built a USB-C powered soldering iron that doesn’t suck.
He is able to drive a regular Hakko iron at 20 V and 3 Amps, providing it with 60 W of input power from a USB-C charger. The Hakko is rated for 24 V operating voltage, so it is running about 16% lower
power voltage. But even so, 60 W is plenty for most cases. The USB-C specification allows up to 5 A of current output in special cases, so there’s almost 100 W available when using this capability.
It all started while he was trying to consolidate his power brick collection for his various computers in order to reduce the many types and configurations of plugs. Looking around, he stumbled on the USB-PD protocol. After doing his homework, he decided to build a USB Type-C charger board with the PD feature based on the TI TPS65986 chip – a very capable USB Type-C and USB PD Controller and Power Switch. The TI chip is a BGA package, so he had to outsource board assembly, and with day job work constantly getting in the way, it took a fair bit of time before he could finally test it. Luckily, none of the magic smoke escaped from the board and it worked flawlessly the first time around. Here is his deck of slides about USB-C & USB-PD [PDF] that he presented at linux.conf.au 2017 Open Hardware Miniconf early this year. It provides a nice insight to this standard, including a look at the schematic for his driver board.
Being such a versatile system, we are likely to see USB-C being used in more devices in the future. Which means we ought to see high power USB Soldering Irons appearing soon. But at the moment, there is a bit of a “power” struggle between USB-C and Qualcomm’s competing “Quick Charge” (QC) technology. It’s a bit like VHS and Betamax, and this time we are hoping the better technology wins.