regular PS and SMPS?!

[deepanger]

ive checked the (ESP car Smps) and found it alittle hard for me!
i just wanna know whats the diff. between a regular regulated
PS unit and that SMPS??!

in the end if i wanna build a simple car PS. unit to power up
say a +25/-25 200watt amp. (based on lm3886) so whats the
most simple design i should go through?
thanks.

 

[AudioFreak]

The basic difference between a linear power supply and a switching power supply is as follows....

linear supply
You have AC from the wall outlet coming into the supply which is then fed thru a transformer, rectified and filtered.

The problem is that transformers only work with AC and in the auto environment you only have DC to play with which is where the switching supply comes in.

switching supply
The basic concept is that you take DC and use an oscillator to drive some transistors. The transistors feed a CT (centre tap) winding of a transformer (step up in this case). Half of the time, the current is fed one way thru the primary and half the time the current is fed the opposite way. The result is that you can now use a transformer to transform the voltage and you end up with some form of AC on the transformer secondaries which can then be rectified and filtered. This is just one type of switching supply, there are many other types.

 

[deepanger]

The basic difference between a linear power supply and a switching power supply is as follows....

linear supply
You have AC from the wall outlet coming into the supply which is then fed thru a transformer, rectified and filtered.

The problem is that transformers only work with AC and in the auto environment you only have DC to play with which is where the switching supply comes in.

switching supply
The basic concept is that you take DC and use an oscillator to drive some transistors. The transistors feed a CT (centre tap) winding of a transformer (step up in this case). Half of the time, the current is fed one way thru the primary and half the time the current is fed the opposite way. The result is that you can now use a transformer to transform the voltage and you end up with some form of AC on the transformer secondaries which can then be rectified and filtered. This is just one type of switching supply, there are many other types.

its much better now!
but cant we use an inverter so we can convert from the DC to AC
then to a simple linear PS then?!
anyway if its impossible to use an inverter ,ineed a more simple
schematic than this in ESP if anybody have one,,

 

[AudioFreak]

You could use an inverter followed by a linear supply but system efficiency will suffer somewhat.

 

[dkemppai]

Out there idea!

Here's one that's really out there, but it may be worth a try. Alternators in cars generate AC, which is rectified into DC. You could tap into the alternator before the diodes (on one phase), and run a transformer off of this. The rest would be a linear power supply. The voltage should be around 12V Peak, and probably not a perfect sinusoid. Actually, it'll probably be more of a trapezoidal waveform, and make better DC in anyway. Transformers may be tricky...

I've thought about this for several projects, but never actually tried it. You wouldn't have any power with the engine off, but...

-Dan

 

[deepanger]

ill try to use an inverter and tell u what happened..
but in the maintime, any companies make a universal PS. for car
amps.?! gonna be much easy to use one of'em..