Increase 2V to 20V

[Rockzinstruz]

Hi all....

I designed the function generator using max038 and output voltage of this circuit is 2v .
My question is,...How I increase the output voltage of the circuit upto 20v..If anybody know the amplification circuit for this problem..Please suggest me..
Important Note:the supply voltage this circuit should be in 5V





Thanks,
Rockzinstruz

 

[4pyros]

You are going to need a higher supply voltage or maybe a charge pump like a RS232 driver maybe.

 

[ronv]

The Max032 puts out +/- 2 volts with a +/- 5 volt supply. So you will need about a +/- 12 volt supply to get a +/- 10 volts from a very good high frequency high power op amp. It will need to be built on a well designed printed circuit board because at 20 Mhz it is more like RF than just an analog signal. Something like this might come close.

https://www.electro-tech-online.com/custompdfs/2012/01/ths3120.pdf

 

[Rockzinstruz]

Thanks for ur idea....is there any transistor based amplifier circuit to improve the output voltage upto 20v.?Suggest me....

Note:the i/p voltge of the function generator using max038 is 2v.and also the supply voltage of the amplifier circuit should note exceed above 5v.

 

[unclejed613]

there's no such thing as a free lunch. you could use a transistor amplifier with a transformer to get the required voltage, but that's the only way you're going to do it with a 5V rail, unless you want to build a DC-DC converter to get the +/-12V for an op amp. (+5V in, +/-12V out)

 

[simonbramble]

You'll need a boost converter. A charge pump will only give you a multiple of the input voltage (and normally only a multiple of 2). Here is my guide to boost converter design:
http://www.simonbramble.co.uk/dc_dc_converter_design/boost_converter/boost_converter_design.htm

 

[Rockzinstruz]

According to your idea...max produce 2v output in 5v supply voltage.yes i need amplification circuit it has to produce 10v output in 12 supply ...
Note:maximum the operating frequency in 1MHz.
Operating frequency is 1Hz to 1MHz.

 

[unclejed613]

what kind of waveform are you amplifying? if it's a sine wave, the op amp needs a bandwidth of 5 Mhz or more. if it's not a sine wave, it should be an op amp with 50Mhz or more bandwidth. the bandwidth is shown as the Gain Bandwidth Product, which means the frequency at which the op amp's gain is 1 without feedback. you are looking for a gain of 5, so the amp needs to be capable of a gain of 5 at 1Mhz. if it's not a sine wave,the amp needs to be capable of amplifying harmonics of the fundamental frequency, which requires a much greater bandwidth. in the chart below, you see where the gain curve crosses 0db (i.e. a gain of 1) at 10Mhz. this particular op amp has a GBW of 10Mhz, and at 1Mhz is capable of a gain of 10 (which is 20db on the chart). this op amp (TLE2072) would work ok at a gain of 5 for a sine wave, but only a sine wave, because with a square or triangle wave, the harmonics (which change the shape of the wave) will not be amplified the same as the fundamental frequency sine wave. within the audio and ultrasonic ranges it will work fine, but as you approach 1Mhz, the lack of amplification for harmonics will make it look more and more like a sine wave.

if you find this kind of confusing, understand that a pure sine wave only consists of it's fundamental frequency. if you have a square wave or triangle wave, it's harmonics of the fundamental frequency that get added to the sine wave that change it's shape. if you pass a square wave through an amplifier that only amplifies the fundamental frequency, the harmonics go away and you have a sine wave again.

 

[Rockzinstruz]

obtained waveform is sine wave ,square wave and triangular wave....at 1Hz to 1Mhz

 

[unclejed613]

obtained waveform is sine wave ,square wave and triangular wave....at 1Hz to 1Mhz

... which will require an op amp with 50Mhz or more bandwidth. while most op amps capable of this are current feedback types, there are some voltage feedback types that will work. here's one with a 70Mhz bandwidth: https://www.ti.com/product/ths4051

make sure you read the data sheet, especially the "circuit layout considerations" on page 20
https://www.electro-tech-online.com/custompdfs/2012/01/ths4051.pdf

 

[kylemaes]

Reversed tranformer? Im not sure if it would work.. It might.

 

[unclejed613]

not over that wide a bandwidth, and it wouldn't maintain the wave shape.... make a transformer that can do that, and you can sell it for it's weight in gold. to keep a reasonably square shape to a square wave, you need to pass up to at least the seventh harmonic AND keep the same phase relationships, so the transformer would need to have AT least a 7Mhz flat bandwidth (1hz-7Mhz) with no phase shifts between harmonics. that's 6 and a half decades of frequency response, it's hard enough to get 4 decades flat response out of an audio transformer (and there are lots of phase funnies in the process).

 

[Rockzinstruz]

How I get the amplitude changes of these 3 waveforms(sine,square&triangular) within the minimum possible specification requirement.
Then anybody know the solution of this problem ,suggest your ideas & views...
At which possible specification ,I design that amplification part?

 

[unclejed613]

errrrr, ummmmm, what?

with an op amp with a gain of 5, you get 5 times out what you put in. if you turn the input signal down to 1 volt, the output will be 5 volts.... at least i think that's what you're asking....

or are you also trying to AM modulate the output? clarify the question......

 

[Rockzinstruz]

As my requirement ,i have to design the amplitude 20v with 1hz to 1mhz operating frequency range.but it's difficult to design the amplifier circuit for 3 waves..each wave having different harmonic frequency .if i design the amplifier circuit for one wave i couldn't use this circuit for another wave ,if i use this wave shape will be change..i have to maintain wave shape also..

Thats why,I reduce my spec amplitude level 12v in 1hz to 1mhz ..

 

[unclejed613]

actually it's quite simple. go to page 25 of the THS4051 data sheet, and build that circuit, with one change. change R4 to 250 ohms. you now have a circuit with a gain of 5 and a bandwidth of 14Mhz, plenty to correctly amplify your function generator output.

either you're over-thinking this, or i gave you too much information to digest (or both)...

 

[ronv]

My guess is he doesn't want to use an op amp - only transistors. Is that it Rock?

 

[Rockzinstruz]

No...just I want to design the possible amplifier circuit as per my spec,whether it's not op amp based or transistor based ...that's not a matter.

 

[ronv]

Then you can use one of the wide bandwidth op amps listed in the posts above.

 

[Rockzinstruz]

OKay..