Convert +12V DC to -30V DC

[oussa]

Hi everybody
I need a schematic of a circuit which converts +12V dc input to -30V dc output, thank you.

 

[eetech00]

search for "Boost Converter"

 

[elektrroda]

you must write how current you need

 

[AnalogKid]

Maximum output current
Minimum output current?
Adjustable?
Isolated?

ak

 

[oussa]

you must write how current you need

I don't know exactly but it is for supplying a rail-to-rail ampliop so it is in the mA range

 

[AnalogKid]

opamp part number?
Circuit schematic?

 

[oussa]

opamp part number?
Circuit schematic?

the opamp is AD820, in the datasheet is wrote that it has a 5V to 30V single supply capability and ±2.5V to ±15V dual supply capability, does that mean that i can't supply it with ±30V??

 

[duke37]

Yes

 

[davenn]

the opamp is AD820, in the datasheet is wrote that it has a 5V to 30V single supply capability and ±2.5V to ±15V dual supply capability, does that mean that i can't supply it with ±30V??

as Duke said, that's correct

single supply it with your +12V

 

[elektrroda]

do you want output symmetrical( i mean voltage will be symmetrical from -U to +U ) , Maybe will be good single supply for this circuit. How circuit you build? you can use single supply , and later use capacitor to filter constant current.

 

[Colin Mitchell]

"the opamp is AD820, in the datasheet is wrote that it has a 5V to 30V single supply capability and ±2.5V to ±15V dual supply capability, does that mean that i can't supply it with ±30V??"

duke37 "yes"

How can you make a mistake like this after being in electronics for 40 years ?????????

 

[duke37]

To Colin
What mistake?
Electrroda said that he can't supply with +/- 30V and I agreed with him.
Of course he could supply with +/-30V but the result would not be happy.

40 years is a bit of an underestimate but I only do it as a hobby.

 

[AnalogKid]

How can you make a mistake like this after being in electronics for 40 years ?????????

What's the big deal? You do it all the time.

ak

 

[AnalogKid]

I need a schematic of a circuit which converts +12V dc input to -30V dc output, thank you.

You can search for a buck-boost or inverting-boost or inverting flyback schematic and get many images. But from the thread it sounds like that is not what you actually need.

For your application circuit, which you still have not posted, what is the input signal voltage range from positive peak to negative peak?
What is the output signal voltage range from positive peak to negative peak?

ak

 

[BobK]

"the opamp is AD820, in the datasheet is wrote that it has a 5V to 30V single supply capability and ±2.5V to ±15V dual supply capability, does that mean that i can't supply it with ±30V??"

duke37 "yes"

How can you make a mistake like this after being in electronics for 40 years ?????????

Unless you are being extremely literal on the word "can't", there is not mistake here. Yes, you can supply it with ±30V, but the result will not be good.

Bob

 

[oussa]

I prefer a linear converter, the input is simply 12V and the output is just -30V, just like that

do you want output symmetrical( i mean voltage will be symmetrical from -U to +U ) , Maybe will be good single supply for this circuit. How circuit you build? you can use single supply , and later use capacitor to filter constant current.

Both of them are fine symmetrical or single supplied the most importint for me is to get -30V.

 

[Colin Mitchell]

Why do you want -30v?

 

[oussa]

Why do you want -30v?

To supply an amplifier

 

[BobK]

If the negative supply is at -30V the positive supply can be no higher than 0V. So why not just supply it with 0 and 30V?

Bob