Switchmode supply
About
This is a sneak preview of a small section of a much larger project I'm working on. It's a power regulation circuit based around the Linear LT1370 switching regulator.
I decided to try my hand at etching a circuit using the toner-transfer method and my results weren't bad — certainly good enough for my needs.
Element 14 were kind enough to sponsor most of the components used in this prototype as a part of their community development program.
Components
- 1x Linear LT1370 switchmode regulator ($14.71)
- 3x AVX TPSD Series 100uF Tantalum Caps ($3.54)
- 1x 18.7kOhm 0603 Resistor
- 1x 6.19kOhm 0603 Resistor
- 1x 10uH SMD Inductor ($1.62)
- 1x MBRD835L Shottky Diode ($1.02)
- 1x TPS730285 LDO ($0.488)
Printed Circuit Board
The circuit board was etched at home using the toner transfer method — printing the design onto glossy magazine paper then using a clothes iron to transfer the etch resist to the copper.
The first board I etched was mirrored because I had flipped the board both horizontally and vertically (only do one of these apparently). The final circuit worked beautifully, despite some ugly jumper wires needed to tie the ground planes together on the single-layer design.
Notes
Artline Ergoline permanent markers are not etch resistant, so my attempts at fixing up the second board were in vain.
The device performs exceptionally well, outputting 5.05V with very slight noise under a medium load — not bad for a switchmode supply.
