power supply help ?

[iugmoh]

I need your help to build power supply to get these voltage levels ( 110VDC , 12VDC , 5VDC ) , I have a transformer (220VAC to 110VAC) and a bridge to get 110VDC but after that to get 12 VDC what I can do ?

[mister_e]

:eek: few choice...
1. use a wall-wart transformer
2. purchase another transformer
3. purchase a ATX power supply, everything is done and almost cheap.
4. build any kind of fancy voltage regulator.

Without knowing your current and safety requirement, it's hard to tell.

[iugmoh]

is there any circuits to build by myself without usin atx power ?

[mister_e]

Well, I don't know of any freebies like that myself, but Google could be your friend.

220 to 110AC would give you with a full rectified wave 110*1.4142~=156 volts.

You still haven't told us your current requirement...

[iugmoh]

oky I have A dc motor work at 110VDC , so I build driver circuits to give us variable voltage to motor , using PWM and PIC

[mister_e]

Again, how much current do you need (ma, A)

[iugmoh]

I need 3A of current

[mister_e]

3A for your DC motor or the rest of the circuit?

[iugmoh]

3A for a motor, thanks mister for your patient

[mister_e]

I'm not a motor professional and I feel It may depend of the motor type you're going to use, but this is what I would try.

The Driver motor will be PWM, so just choose Mosfet/IGBT one who can handle your current and voltage range + certain amount of safety.

Your software will handle the voltage range by reducing the PWM duty cycle. You should monitor the voltage across your motor using a PIC adc pin like regular voltage regulator do. This way you ensure to have smooth and constant voltage, and why not monitor the current as well to add some safety to it?

Maybe the following links would help.
http://f-cpu.seul.org/~nico/astromech/motor_control/tipntrick_motor.pdf
http://ww1.microchip.com/downloads/en/AppNotes/00894a.pdf
http://ww1.microchip.com/downloads/en/AppNotes/00898a.pdf
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2125&param=en026178

How much current you need for your 12V line?

[iugmoh]

I need a help to this problem , I have these things :
1) ATX power supply with +5v GND GND +12V
2) a transformer from 220 to 110 and a bridge to get +110V and GND

but when I connect the two grounds of ATX power supply to GND of bridge (after a transformer) then the circuit breaker is down. and disconnect all connections to these terminals but the porblem is the same I don't know where is the probelm.
I measure from GND of ATX to positive terminal of bridge it gives me +50 but with the GND of bridge it gives me -50V ???????///

I need help ?