Post by sandyk on Jun 12, 2014 0:57:30 GMT
Presently, I am experimenting with a Greg Erskine designed JLH Add On PCB, that has been cut in half, and has an LM317T voltage regulator
replacing the Current Limiter section. The idea is to use the PC's +12V SMPS supply to provide a squeaky clean, low noise and low impedance +5V supply for an internal 120GB SSD, which may be used to store some of my highest quality .wav files, or perhaps even for the OS drive.
I have drilled an extra hole in the PCB, but if one of the resistors was mounted under the PCB with a little section of the earth track exposed
for soldering, the additional hole would not be needed. There is an additional 100nF capacitor mounted across the IN terminals under the PCB
for voltage regulator stability reasons.
Using 110 and 330 ohm 1% metal film resistors for the Adjust terminal, the output voltage measured was 4.984V.
If it works out as hoped, it could also be used at different voltages where a medium current high quality regulated supply is needed.
At lower currents, a single heatsink would be all that is needed. As this PCB is running at only +5V output, the 10K resistor has been replaced by a J506 Current Regulating Diode of approx.1.4mA. This further enhances operation at voltages as low as +5V and 3.3V.
The large electrolytic capacitors shown are 4,700uF 10V Low ESR, and a 4,700uF 16V normal type electrolytic capacitor in parallel.
This gives a simulated capacitance of approximately 1FARAD.
PCB markings of -V IN and - V OUT are in this instance, actually +VIN and + V Out.