blasphemy000
New member
Hello all. This is my first thread on here, although I've been doing a lot of reading and learning from your website. I want to say thank you to the operators of this site for the wealth of information that is on here.
Anyways. On to the miniature power supply.
I'm in the designing and testing phase of building a 25V@250A SMPS to be used for TIG welding. Currently I'm waiting for parts to build the second, low-power, test model(25V@25-50A). While designing this large supply I have realized that I will be in need of an auxiliary/standby power supply to power the little controllers and such, so for the low-power test model of the welder I tweaked this design I found online using a TNY276 controller and what I think is an E20/14/5 transformer I pulled from a PC power supply. For the full-power version of the welder I will be building a larger auxiliary supply to ensure that I have enough power to drive the array of IGBTs that will be used(the switching IGBTs and the LARGE(300A) output chopper IGBTs), but for the low-power model this little supply has proven enough. Anyways. Here's the supply. I only have the PDFs of the schematic and the PCB layout. I can't find the USB cable for my camera but when I do I'll post a picture of the finished supply. I fit it neatly on a hand-drawn(with sharpie and a ruler) PCB measuring 2.25x3.00 inches.
Also, the website that I took the design of this PSU from says it will run on anything from 100-240VAC. I'm in the USA so wall power is only 120VAC but I did have it running off my isolation transformer at 86VAC and I've ran it plugged into the wall at 120VAC. I haven't tested it at 240VAC because there's really no need to for what I'm using it for.
Unloaded this PSU draws <10mA from the wall and fully loaded draws just 50mA. Output feedback is through a 15V zener and an 817CN optocoupler giving an output voltage of 16.1 - 16.2VDC. I've only loaded this PSU up to 350mA because above that current the tiny transformer has a high-pitched ring/hum. Nothing gets hot or anything like that, but I'm sure the vibration is bad.
View attachment Board Design.pdf
View attachment Schematic.pdf
Anyways. On to the miniature power supply.
I'm in the designing and testing phase of building a 25V@250A SMPS to be used for TIG welding. Currently I'm waiting for parts to build the second, low-power, test model(25V@25-50A). While designing this large supply I have realized that I will be in need of an auxiliary/standby power supply to power the little controllers and such, so for the low-power test model of the welder I tweaked this design I found online using a TNY276 controller and what I think is an E20/14/5 transformer I pulled from a PC power supply. For the full-power version of the welder I will be building a larger auxiliary supply to ensure that I have enough power to drive the array of IGBTs that will be used(the switching IGBTs and the LARGE(300A) output chopper IGBTs), but for the low-power model this little supply has proven enough. Anyways. Here's the supply. I only have the PDFs of the schematic and the PCB layout. I can't find the USB cable for my camera but when I do I'll post a picture of the finished supply. I fit it neatly on a hand-drawn(with sharpie and a ruler) PCB measuring 2.25x3.00 inches.
Also, the website that I took the design of this PSU from says it will run on anything from 100-240VAC. I'm in the USA so wall power is only 120VAC but I did have it running off my isolation transformer at 86VAC and I've ran it plugged into the wall at 120VAC. I haven't tested it at 240VAC because there's really no need to for what I'm using it for.
Unloaded this PSU draws <10mA from the wall and fully loaded draws just 50mA. Output feedback is through a 15V zener and an 817CN optocoupler giving an output voltage of 16.1 - 16.2VDC. I've only loaded this PSU up to 350mA because above that current the tiny transformer has a high-pitched ring/hum. Nothing gets hot or anything like that, but I'm sure the vibration is bad.
View attachment Board Design.pdf
View attachment Schematic.pdf
