I was frequently questioned if my design of the Moog Ladder runs at 12V. The answer is yes. You can run it at 12V out of the box. However the performance at 12V can be optimized by changing a few resistors.
– R47 and R13 from 13k to 11k (Diode bias current for LM13700).
– R56 and R2 from 13k to 10k (I_abc for LM13700).
Low ripple PSU with LM317
This PSU is build around the well known LM317 and follows mostly a straight forward design as in the data sheet. To mention is an additional filter before the LM317 to lower the ripple. With this filter the ripple is down in the noise floor. I have tested this design with a current load of 1.2A for some hours. No problems whatsoever. Because the heat sink is not that big I recommend keeping the load below 1A. It is getting quite hot though. For a +/- PSU you need two of those. You can daisy chain them and use the connection as ground.
Low ripple PSU with LM317 schematic
The design is straight forward like in the data sheet of the LM317. The led indicates the presence of the unregulated voltage before the LM317. R2, R5 and C5 builds a RC input filter between the reservoir capacitor and the regulator. The resistors should kept low and the capacitance high. The filter sinks the ripple below the noise level of the regulator. You have some loss of efficiency due to the voltage drop across the series resistor. All protection features of the LM317 regulator are preserved.
Low ripple PSU with LM317
Low ripple PSU with LM317
Small variable PSU with LM317 / LM337
It comes in handy to have a small PSU with variable output voltages around to test modules with different voltages or drive small projects. The emphasis is on driving small projects. Tests are better done with a lab PSU. I just made a small PCB for a +/- 12..17V with LM317 and LM337. There is nothing special about it. Straight forward design. Because it is small the heatsinks are not that big and close together. Don’t drive it to hard.
Small variable PSU with LM317 / LM337 schematic
Small variable PSU with LM317 / LM337
Small variable PSU with LM317 / LM337