Help needed in push-pull circuit for Inveter.

Hi,

Yeah i would not be surprised if every modern converter on the market today uses a uC chip (DC input, AC output). Many PC power supplies sill use the old TL chips or similar but that's a DC output with AC input.

I think he's looking for ultra simple single pulse type 'modified' sine converter.

It sort of cracks me up that they even call that a "modified sine". Yeah it's modified alright, modified soooo much that it's not even a sine anymore but just a pulse <big chuckle to follow>.

RITESH KAKKAR said:

Hi,

I am making/testing small MOS-based Inverter in which the freq is generated from 555 and as per diagram IRF540 is used the output transformer is of 12-0-12V to 220V i found when the one side of mos is connected at certain freq the output of inverter was 130-134V and when other part was connected the output voltage reduce to 40-45V.
so, why the push pull circuit is not giving double voltage as it should be please give me solution of it!


Thanks

Click to expand...

Why make it more difficult than it needs to be? Here's a design I came up with a few years back (attached). If you don't require logic control, so much the better. Use a MC74HC04A hex inverter as the driver. Connect three of its gates in parallel to drive each phase. These can source/sink 20mA each, so that's 60mA of possible drive current.

Figure the operating frequency:

f= 1 / [2ln(2)RC] (Where C is the timing capacitors C3-4 and R is the base resistors R5-6)

If you're using a common, line frequency xfmr, set the frequency to 50Hz or 60Hz, as applicable. No duty cycle problems as the collector coupled multivibrator generates two signals in anti-phase naturally. The use of a CMOS logic gate as a driver unloads the oscillator to improve its frequency stability.

Used this to make a 12Vdc-to-4KVdc inverter that runs at 21.6KHz. Works just great.

Interesting, whats the control input from?

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This inverter is a subsystem for a basic "light show" made from an ES CRT. This was part of the +/-2000V needed to light up the CRT. The deflection voltages coming from the R and L channels of a stereo. This draws random squigglies on the screen.

The CNTL signal was derived from a logic circuit that sensed the absence of a signal that prevented a dead spot from staying on the screen. When the CNTL line drops, the driver transistors cutoff, removing the high voltage from the CRT.

Miles Prower said:

^
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This inverter is a subsystem for a basic "light show" made from an ES CRT. This was part of the +/-2000V needed to light up the CRT. The deflection voltages coming from the R and L channels of a stereo. This draws random squigglies on the screen.

The CNTL signal was derived from a logic circuit that sensed the absence of a signal that prevented a dead spot from staying on the screen. When the CNTL line drops, the driver transistors cutoff, removing the high voltage from the CRT.

Click to expand...

Cool

Anyway, i have gone to UPS production company in my town the owner was an Engg he inform me that in my circuit to add the short ckt protection at every Mosfet. please help.

can one here can help me with this...??

Hi,

The SG3524 is working but the problem is the square wave which is not efficient as more current is draw at no load than modified sin wave...
can u please help me with modified wave circuit with voltage regulation..

thanks