Hello All,

I want to generate a 0 to -30 V Sine Wave @ 60 - 100 Hz frequency. Any suggestions ???.

 

What's a "-30 V Sine Wave"? Sine waves don't have a (+) or (-) polarity.

So let's assume you want to generate a 30 volt sine wave. Is that 30 volts RMS? Or 30 volts peak? Or 30 volts peak-to-peak? Also, how much current does this device have to supply (or, alternatively, what load resistance must it drive)?

 

It's a 30 V Peak to Peak Sine Wave.
The Load will draw 500 mA current from it.

 

It's a 30 V Peak to Peak Sine Wave.
The Load will draw 500 mA current from it.

Do you want a wave with some arbitrary frequency between 60 and 100 Hz or do you need it to be adjustable across that range?

A 12V transformer will do the job if you live in a 60Hz land.

 

Pure sine waves can be tricky. What percentage distortion is tolerable?

 

It's a 30 V Peak to Peak Sine Wave.
The Load will draw 500 mA current from it.

In that case, a suitable 60Hz - 100Hz oscillator circuit followed by an audio power amplifier chip such as an LM1875, or something a bit more powerful like an LM4766, would do the trick.

 

Or, an automotive subwoofer amplifier fed by an audio generator. And a AC voltmeter to show 30V peak to peak as 10.5 RMS AC when adjusting the gain knob.

----> https://www.ebay.com/itm/DC-12V-25V...hash=item3d36765649:m:mkZ0GWQyOKKgAOCw_EDzP2Q

----> https://www.ebay.com/itm/12V-24V-TP...138062?hash=item282139f44e:g:1MIAAOSwTA9X6iL6

 

If the load can "float" (no connection to circuit common/"ground"), a class D (switching) stereo audio amp configured for a "bridge tied load" (BTL) would be simple, the efficiency would be high and it would run on a single supply of probably 18 volts or greater. This is the type of amp in Externet's link, above. It is actually two amplifiers already configured for BTL. There are similar boards that can be used for either two separate channels or configured for BTL with a jumper or two.

If BTL isn't acceptable, a switching amp still is efficient and comparatively simple, but it will require a "split"/"dual"/"bipolar" (positive and negative) power supply. Buying a ready-to-use amplifier board off the shelf is probably still possible, but they are less popular because of the power supply requirement.

 

I just noticed the waveform generator in Externet's link is called "DDS" ("... ICL8038 DDS Signal Generator ...") which means direct digital synthesis. It is no such thing. I doubt the term had even been coined when the ICL8038 was designed by Intersil many decades ago. But the 8038 is still a decent part for the job.

 

Maybe the TS want's to do this?

 

Maybe the TS want's to do this?View attachment 146902

No, the TS clarified in post 3...

It's a 30 V Peak to Peak Sine Wave.
The Load will draw 500 mA current from it.

 

Maybe the TS want's to do this?View attachment 146902

Yes this is exactly what i want. With the negative Voltage going till -30 V.

I'm trying to explore the configuration suggested by Externet where Sine Wave Signal required will be generated in first Stage by ICL8038 and in secound stage it will be amplified by TPA3116D2.

Now i want the signal to produce Max and Min Voltage between 0 and -30 V. Can i acheive the same using this configuration. ???