Autore Topic: Multi-alimentatore  (Letto 2779 volte)

daniele redivo

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« il: 14 Maggio 2018, 10:16:50 »
io ho realizzato un alimentatore multiplo per c64,c128,1541-II:
ne ho realizzati una decina ed ho avuto buon feedback. L'ultima versione fornisce 5A in servizio continuo sui 5V, da cui si possono alimentare per es. un 128, un 64 e due 1541-II assieme.
Ho usato un trasformatore e de DC DC converter switching. Riguardo al ripple, anche a 5A , resta sotto i 50mV peak-to-peak.
Inoltre ha la protezione da sovravoltaggio che scatta a 5.7V.
Se a qualcuno può interessare...

Copio ed incollo il post che avevo messo su un altro forum:
I have been working on this for quite some time now:
but using most popular DC/DC boards (XL4005 or XL4015) to drive the 5V line, I always stopped when reaching 3A as rated output, that means powering at most C128+REU or other stuff on exp port+1541-II.
In order to go further like C128+multiple 1541-II or C128+C64+.... I developed a PSU using parallel DC/DC regulators. Typical designs found around internet foresee the use of coupling resistors or diodes to do the load sharing between the converters. This I wanted to avoid since series resistors or diodes cause a lot of voltage drop and heat.
My design is this:

I use 2 DC DC parallel boards (slave + master) for 5V and one for 12V. The load sharing between the parallel boards is done by balancing their output currents, so I use an ACS712 (hall effect current sensor) in series with each DC DC board and then read the ACS712 outputs with an op amp which controls the feedback of one DC DC board (slave). The other DC DC board is the master and works with fixed feedback as normal. So basically the slave board current output follows the master one.
There is also an overvoltage protection based on MC3423+SCR (with self resettable fuses) and a test button for checking from time to time that the protection is in good health.
The results can be found below.
C128+1541-II+C64+1541-II. After about 1 hour running Transformer core temperature has risen from 20°C to 50°C (well inside transformer limits which is rated class F):

Inside the PSU:

Full load ripple on 5V line is around 45mV:

And around 14mV at no load:

5V line stability: I turned OFF and ON the C64 while checking the voltage inside the C128. Line is VERY stable.

Overvoltage protection test:

Checking 5V line in two points: inside PSU and at C128 userport.

Power ON sequence:

Power OFF sequence:

MOD - Thread separato. Non riesumare vecchie discussioni cambiando argomento. -eregil
« Ultima modifica: 14 Maggio 2018, 17:23:10 da eregil »