[SOLVED] Pic 16f876a Pure Sinewave inverter

[Californiajoe]

GLCD needs more power, those two regulators are not strong enough.

Regards

 

[jami007]

how much current glcd need? what is its maximum power consumption?

 

[Californiajoe]

Very close to 100mA for Monitor_Inverter complete. I'll test suply of it over LM2940S-10.

Regards

 

[jami007]

hmmmmmm....its an excellent idea....

best regards

 

[Californiajoe]

Take a look into those pictures, C43 is not included into our circuit scheme?

Regards

 

[jami007]

but if we connect it in our circuit, and take output from in b/w Resistor and Capacitor it behaves like a low pass filter, what do you think?

---------- Post added at 17:37 ---------- Previous post was at 17:30 ----------

also if we connect it in our circuit, cutoff frequency will be 33.8799kHz, so i think it is connected to filter un wanted high freq. signals/distortion

 

[Californiajoe]

I don't know what to think, it is on the original datasheet. I'll test it some day for sure. Could be for filtering high freq. distorsions.

Regards

 

[jami007]

ok. Then post your results. Best wishes

 

[Californiajoe]

New testing version of Inverter_Monitor in Proteus.

Regards

 

[jami007]

what are your test results about low pass filter???

 

[Californiajoe]

I didn't test it yet, at the moment I am playing around Inverter_Monitor.
BTW, I found these days one quite good tip about the output mosfets. Every transistor should have resistor (1kohm) connected between gate and source. Resistor prevent appearing of electrical charge on gate, which can couse conductance in the wrong time.

Regards

 

[jami007]

hmmmm........ok my juniors just start working on this inverters so i'll let you know while we test it

Best regards

 

[daniello_85]

Hello jami007, CaliforniaJoe and everybody. I attache my desing in Orcad 9.2. I upload the schematic. I fedback all my analog signals, I remove the trimmers but it doesn't work the inverter. My problem is the output voltage drops 30V when i connected the lamp of 50W. Also I've test the blanking time of the mosfet on the same branch. Look the picture

Now i'm doing test. I will put a list with all components of this inverter for people can buy in Digikey.

Note: This design is output for 150W

Best regards
Daniel

 

[Californiajoe]

daniello_85, can you make a pdf file of your schematic?
regards

 

[daniello_85]

Yes!This file is my schematic
Best regards

 

[Californiajoe]

Quick look!
You don't use original mosfets? Also TLP250, pin 6 and pin 7 should be connected?

Regards

 

[daniello_85]

Hi Californiajoe
You are right, but my mosfet are totally compatible, even are less rds(on). I think that pin 6 and pin7 don't be connected. Look the datasheet! My inverter is the 150W, I think that i don't need eight mosfet.

What's do you think??
Best regards

 

[Californiajoe]

I think you need 8 mosfets, you have only 4 so that is the reason for loosing voltage with load, also I recomend to you to connect together pins 6 and 7 on TLP 250.
Also one more thing: make PCB connections around mosfets stronger(speciali for D and S pins).

Regards

 

[daniello_85]

Hello CaliforniaJoe
I did a new stage power, I connected pin 6 & 7 and i used 8 MOSFETs. Look the picture that i attache. Also I tested the Vgs between MOSFETS in branch A with the osciloscope, I think that "blanking time" is my problem. Thank you very much for you help

Regards

 

[Californiajoe]

Few posts back I mentioned resistor 1kOhm connected between gate and source. Also can you make photos of the output sine wave with and without load.

regards