Low cost DC to AC converter / inverter

[jenard1605]

Hi guys,

I build this circuit out of curiosity to make DC to AC converter for my workbench (sorry 'bout the drawing in it). Try to configure this i use 555 timer to generate 120hz to make the flipflop generate 60hz then I added 10k, 1k resistor and a 1uF resistor then i use a d flipflop as my inverted output at the same time i used it as driver of H-bridge n-type mosfet (feel free to choose any) then i use 7805 ic to power up the timer and flipflop..... why d-flipflop? Because its cheap that simple...

 

[andre_luis]

Are you saying that the FF was able to drive the bridge and worked fine without any additional circuit to ensure dead-time / voltage shift ?

 

[FvM]

"I build this circuit" should be read as "I didn't yet operate it"?

 

[jenard1605]

To andre: it was given that FF output current is max of 20ma said on the datasheet if your looking at 1.... ofcourse it can drive low-profile (low power) mosfet... duh.... i used it on my project at school..... but if you want more sophisticated device i prefer use sg3524n... please be reminded to read the datasheet carefully.......

 

[dick_freebird]

How much more would it really cost to use a designed H-bridge
driver IC to buffer the DFF's output up to reasonable sized FET
gate loads? Or are you looking for a trivial output current on
this project (claiming a DFF can drive a power FET, might be
true in some sense for some size of FET, but liable to be a
disappointment). I would expect the gate transition times to
be rather leisurely and prone to cross conduction in the bridge
legs.

 

[jenard1605]

Well... to tell the truth our professor challenge us to built a circuit using DFF as part.. to give an Alternating output atleast upto 100mA enough to drive a motor in 60hz frequency... the only parts i do have is 2n7000 and a 555timer... but if you have any suggestions please let me be advised....

 

[schmitt trigger]

The 2n700 is a very small mosfet. it has a typical RDSon of 1.2 to 5 ohms. And that is with a very low 60 volt breakdown voltage.

As others have mentioned, you may still use a D flip flop to generate the basic timing signals, but a legitimate bridge driver, with high voltage withstanding and current sourcing capabilities, plus dead time adjustments, is necessary to properly drive an AC-motor capable inverter.

For instance: http://www.irf.com/product-info/datasheets/data/ir7184s.pdf

 

[FlapJack]

What voltage is the motor you have to drive.