Negative Voltage Offline SMPS

[[email protected]]

Good day everyone,

Can anyone shed some light on making a negative DC voltage
mains(offline) SMPS?

I've designed quite a few offline switchers, but i've always created
+9 or +12V DC with them. Now, I have a requirement for a -48V DC
Power supply that runs off of mains (65-280VAC) power. Incidently, I
need it to give me about 4A (200W).

I'm familiar with offline switchers, and I know the dangers and
precautions.

Any help greatly appreciated!
Ben

 

[[email protected]]

Oh, Also, Space is tight. All of the offline switchers I've made in
the past have been somewhat physically large - can anyone give me some
tips for lowering the size of the footprint (Especially the HEIGHT).

Thanks again!
Ben

 

[John Popelish]

Good day everyone,

Can anyone shed some light on making a negative DC voltage
mains(offline) SMPS?

I've designed quite a few offline switchers, but i've always created
+9 or +12V DC with them. Now, I have a requirement for a -48V DC
Power supply that runs off of mains (65-280VAC) power. Incidently, I
need it to give me about 4A (200W).

I'm familiar with offline switchers, and I know the dangers and
precautions.

Any help greatly appreciated!
Ben

Design an isolated +48 volt supply, and use the positive
terminal as the common.

 

[John Larkin]

Good day everyone,

Can anyone shed some light on making a negative DC voltage
mains(offline) SMPS?

I've designed quite a few offline switchers, but i've always created
+9 or +12V DC with them. Now, I have a requirement for a -48V DC
Power supply that runs off of mains (65-280VAC) power. Incidently, I
need it to give me about 4A (200W).

I'm familiar with offline switchers, and I know the dangers and
precautions.

Any help greatly appreciated!
Ben

Umm, reverse the outputs?

John

 

[Eeyore]

Good day everyone,

Can anyone shed some light on making a negative DC voltage
mains(offline) SMPS?

I've designed quite a few offline switchers, but i've always created
+9 or +12V DC with them. Now, I have a requirement for a -48V DC
Power supply that runs off of mains (65-280VAC) power. Incidently, I
need it to give me about 4A (200W).

I'm familiar with offline switchers, and I know the dangers and
precautions.

Any help greatly appreciated!

ALL power supplies can be negative ones by connecting the '+' output to
ground.

Graham

 

[Eeyore]

Oh, Also, Space is tight. All of the offline switchers I've made in
the past have been somewhat physically large - can anyone give me some
tips for lowering the size of the footprint (Especially the HEIGHT).

Use low profile components maye ?

Surely you could have thought that one through ?

Higher switching frequencies reduces the size on many of the components
required too.

Graham