Need help with 100 volt DC power supply

[multiport]

Hello,
I need a power supply which outputs 100 volt DC, and at least about 10-50mA. Preferably it would be variable from 0-100 volts (in steps of 5 or 10 volts is totally ok, and if it is quite simple I don't need it to be variable, I can build a few with different output). I have 230v AC mains, should it be done with a transformer and rectifier and something more, or would it be easier to step-up for example 12 or 24 volt DC?
Is it possible to use an op-amp to step up voltage to 100 VDC? Or are there any step-up/step-down/regulator chips that could be used? Or would it work to use a "lighting dimmer" for 230VAC and then rectify it's output? That would be simple, but would it work?

 

[canadaelk]

Modify the circuit in this app note, fig 4, https://www.electro-tech-online.com/custompdfs/2012/01/AN-D10.pdf, to suit your needs. E

 

[multiport]

Some of the components there seem to be really hard to find here where I live, do you have any other suggestions? At least the VN0650N3 I can't find anywhere, and the LND150N3 has to be ordered from far away..

 

[ronv]

If you can make it with 20ma look at this one. It is available from mouser in the US.

https://www.electro-tech-online.com/custompdfs/2012/01/LR8.pdf

You should use a transformer (230 to 115) to isolate it from the mains. A bridge and filter capacitor.

A transformer wouldn't like the dimmer idea.

Let me know if you need a diagram or if the datasheet is good enough.

 

[bountyhunter]

Hello,
I need a power supply which outputs 100 volt DC, and at least about 10-50mA. Preferably it would be variable from 0-100 volts (in steps of 5 or 10 volts is totally ok, and if it is quite simple I don't need it to be variable, I can build a few with different output). I have 230v AC mains, should it be done with a transformer and rectifier and something more, or would it be easier to step-up for example 12 or 24 volt DC?
Is it possible to use an op-amp to step up voltage to 100 VDC? Or are there any step-up/step-down/regulator chips that could be used? Or would it work to use a "lighting dimmer" for 230VAC and then rectify it's output? That would be simple, but would it work?

This is actually pretty easy to do if you use a transformer and FWB to generate an unregulated voltage of about 115V. You would also need a second very low current bias rail of maybe 15 - 20V to run the op amps and references. I have attached a generic linear regulator schematic which could easily be dialed up for 100V output, just adjust some resistor values and use higher voltage transistors on the pass transistors and the small NPN which drives them.

 

[canadaelk]

News from TI. I only glanced through the dadasheet (oops, datasheet), but it looks like it could do the trick: http://ca.mg5.mail.yahoo.com/neo/launch?.rand=5m52hkqaelfpd. E

 

[alec_t]

Have you considered an off-line SMPS chip such as NCP1010AP?

 

[multiport]

If you can make it with 20ma look at this one. It is available from mouser in the US.

https://www.electro-tech-online.com/custompdfs/2012/01/LR8.pdf

You should use a transformer (230 to 115) to isolate it from the mains. A bridge and filter capacitor.

A transformer wouldn't like the dimmer idea.

Let me know if you need a diagram or if the datasheet is good enough.

This looks quite good and I think the datasheet is enough, but I looked at one 230 ->115v adapter which said it was an autotransformer so I started to think if it is a good solution after all. But maybe I can use some other transformer. Or would it work to use an optocoupler directly on the output? Or do they work like that at all? This should handle the voltage: https://www.sharpsma.com/webfm_send/1358 or am I wrong, the "reverse voltage" is only 6 volts but the collector-emitter voltage looks ok. Maybe some normal 230->115v transformer is better after all.

 

[ronv]

You should use an isolation transformer like the first one on this page.

https://www.mouser.com/Power/Transf...zsna4Z1yzsn7lZ1yzutluZ1yzutlnZ1yzuxrrZ1z0wbui

 

[multiport]

Thanks, I think the 553-FS120-02 there looks good, it costs about 20% of the ones I had looked at earlier so it fits my budget perfectly.

 

[ronv]

Just the right size.