AC Rectified - DC Mosfet dimmer - Hints please

[Benta]

 

I never directly answer any one persons issue directly.

Fine.

That FET is pretty dinky.

It's an industry-standard IRF730.

I'm doing 480Hz quite often.

Fine.

My gates are at least six times that capacitance.

And? That would make matters worse.

I also don't allow short pulses at either end of the duty cycle.

20KHz was mentioned.

Not by me.

There doesn't seem to be any practical reason to have a resistance that high.

Do the calc.

As long as you are aware.  This is for those that might consider copying parts of your circuit.

Yes. We're warned.

[TJ232]

Any specific reason that you are not looking also to a more classic solution, with ZCD and Triac?

You can find a nice example here:


It has all the MAINS related funtions onboard (including phase detection, ZCD,etc), you just need to provide a VCNT voltage control to drive it. Voltage control can be provided by a DAC, PWM, even a 10k pot between Vcc and GND with the viper on VCNT input pin

Also on the same channel you can find a lot of AC dimmer implementation tutorials with ESP8266, Domoticz, RaspberryPI, etc .

Happy Easter!

[bingo600]

Any specific reason that you are not looking also to a more classic solution, with ZCD and Triac?
..

Happy Easter!

I am interested in PWM'ing the dimmer , and avoid ZCD issues.

For me the "DC" dimmer is "elegant" ,  i do think i'll put in a small 12v 500mA psu , and see if i can get rid of the capasitive psu.
Just bought a few small ones.

I have seen your page(s) , nice projects. But i'd like to go with the DC version.
Happy easter to you too.

Ps: My EE friend says a 10uF/400v would be suficcient , if one goes down that route.

/Bingo

[bingo600]

Any specific reason that you are not looking also to a more classic solution, with ZCD and Triac?
..

Happy Easter!

I am interested in PWM'ing the dimmer , and avoid ZCD issues.

For me the "DC" dimmer is "elegant" ,  i do think i'll put in a small 12v 500mA psu , and see if i can get rid of the capasitive psu.
Just bought a few small ones.

I have seen your page(s) , nice projects. But i'd like to go with the DC version.
Happy easter to you too.

Ps:
My EE friend says a 10uF/400v would be suficcient , if one goes down that route.
And that i should use a 100nF X2 after the diode bridge , to be nice to the environment.


/Bingo

[TJ232]

Any specific reason that you are not looking also to a more classic solution, with ZCD and Triac?
..

Happy Easter!

I am interested in PWM'ing the dimmer , and avoid ZCD issues.

For me the "DC" dimmer is "elegant" ,  i do think i'll put in a small 12v 500mA psu , and see if i can get rid of the capasitive psu.
Just bought a few small ones.

I have seen your page(s) , nice projects. But i'd like to go with the DC version.
Happy easter to you too.

Ps: My EE friend says a 10uF/400v would be suficcient , if one goes down that route.

/Bingo

Thank you

But what's so appealing about PWM'ing the dimmer in that way, what do you consider to be the main advantage of it?

[Zero999]

Any specific reason that you are not looking also to a more classic solution, with ZCD and Triac?
..

Happy Easter!

I am interested in PWM'ing the dimmer , and avoid ZCD issues.

For me the "DC" dimmer is "elegant" ,  i do think i'll put in a small 12v 500mA psu , and see if i can get rid of the capasitive psu.
Just bought a few small ones.

I have seen your page(s) , nice projects. But i'd like to go with the DC version.
Happy easter to you too.

Ps: My EE friend says a 10uF/400v would be suficcient , if one goes down that route.

/Bingo

Thank you

But what's so appealing about PWM'ing the dimmer in that way, what do you consider to be the main advantage of it?

Advantage compared to what? A huge variable transformer?

Personally, I'd prefer to use good old fashioned phase control.

[TJ232]

Any specific reason that you are not looking also to a more classic solution, with ZCD and Triac?
..

Happy Easter!

I am interested in PWM'ing the dimmer , and avoid ZCD issues.

For me the "DC" dimmer is "elegant" ,  i do think i'll put in a small 12v 500mA psu , and see if i can get rid of the capasitive psu.
Just bought a few small ones.

I have seen your page(s) , nice projects. But i'd like to go with the DC version.
Happy easter to you too.

Ps: My EE friend says a 10uF/400v would be suficcient , if one goes down that route.

/Bingo

Thank you

But what's so appealing about PWM'ing the dimmer in that way, what do you consider to be the main advantage of it?

Advantage compared to what? A huge variable transformer?

Personally, I'd prefer to use good old fashioned phase control.

This was actually also my question, a more classical phase control solution with ZCD and Triac versus the DC PWM MOSFET as above.

[mrTheWheel]

@Benta,

Can you please provide me the schematic of your improvements for a AC PWM dimmer circuit?

It seems dimmable LED bulbs need PWM. I wanted to build the revised circuit (the one without the red cross) but indeed the big 400volt capacitor is not going to fit in a small enclosure so I like your idear of placing the cap. between the R4/R5.

Thanks in advance!