i'm trying to construct the following dc to dc converter.
Input: 12Vdc 3A output: 5Vdc 3A
but i'm getting no output, any ideas ?
Asked
Active
Viewed 323 times
0
-
- Where is your voltage reference? Your circuit is missing one (If you are trying to replace 7805). 2. Your 7805 has shorted input to output.
– Chupacabras Dec 14 '18 at 15:34 -
There are several examples to upgrade from 1 Amps of an 78xx device. I think, when you look into datasheets you most probably find better solutions. – Tom Kuschel Dec 14 '18 at 15:43
1 Answers
1
Q3 needs to be turned on to provide current to the load. To turn it on you need to draw base current via the emitter and from the positive rail (in red). I see no conduction path that can achieve this; everything that connects to the base ultimately connects to the positive rail and hence there can never be any base current and there can never be any output voltage.
There may be other problems too but this seems to be the most fundamental. To be honest, the design looks a mess.
If you want a simple and effective 5V 3A design try this questioner's circuit that was posted an hour or two ago.
Andy aka
- 456,226
- 28
- 367
- 807
-
What would you like to supply with power, because switching regulators are not always suitable? – Tom Kuschel Dec 14 '18 at 15:51