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Another INVERTER we can talk about..


Guest Kasamiko
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oh i see.....then is there IC would replace the previous 1? and the multiplier in the circuit..what is the usage?? just multiply the current or it have other usage? and its port connected to an XOR to invert the waveform ?? because the input from the multiplier is always big so it is 1 and the function generator will give 1 and 0 so the output from the XOR will be inverted??? ??? ???

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the XR 2206
port connected to an XOR to invert the waveform ??

The output current from the MM5369 is very low, so an XOR is used to increase the current. It doesn't need to be inverted and works the same if it is inverted or not.

because the input from the multiplier is always big

The MM5389 will try to give a 12V output but is clamped to 5V by the input protection diodes of the XOR.

so it is 1 and the function generator will give 1 and 0 so the output from the XOR will be inverted???

The function generator needs a perfect square-wave at its input. The output of the MM5369 is not perfect, it has assymmetry, so the XOR drives a filter.
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if so...then i can straight use the xr2206 by changing the value of the capacitance and resistance shown in the datasheet to get 50HZ? in the datasheet there is many ways to generate the sine wave...which 1 should i choose? sinewave generation without external adjustment or sinewave with minimum harmonics distortion? and what is the different between this 2 circuit? thanks ;D

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can i add more mosfet and caps to increase it performance aslo efficiency??

Of course adding Mosfets will result in the same total amount of power wasted as heat because the Mosfets operate as a linear amplifier. Therefore the low efficiency will be exactly the same.
You could add more Mosfets to share extra heat and get more power output.

Which caps have anything to do with efficiency?

why we want to invert the signal from XR2206??

The transformer is driven push-pull so the Mosfet on one side needs its drive to be inverted.

why we need to have voltage reference 6V??

All opamp circuits need a DC reference voltage. This one is half the supply voltage.
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is there any alternative way to increase the efficiency without using the pwm??

Make the circuit switch and produce a modified sine-wave that is a square-wave with a couple of steps in it. Switching circuits are much more efficient than linear circuits.
Use a ferroresonant transformer with a square-wave driving it.

and the negative feedback u meant is used for??

It keeps the output voltage regulated so that it doesn't drop with loading.
It also keeps the output a sine-wave when a non-linear load tries to make it distorted.
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This is a linear sine-wave inverter and it wastes a lot of power and its output Mosfets get extremely hot because they conduct a high current all the time.


Did you consider that the MOSFETS run for a long time in their "Ohmic Region" as the cause of them getting hot?

Since the current, like the voltage, is a sinusoid, at "crossover", the MOSFET's shouldn't  be conducting any current at all.



All opamp circuits need a DC reference voltage. This one is half the supply voltage.


As a general statment, that's a little misleading to those that aren't familar with op-amp circuits. Yes a reference is chosen, but it can also be ground just as easly as a DC... or for that matter, an AC signal.
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Make the circuit switch and produce a modified sine-wave that is a square-wave with a couple of steps in it. Switching circuits are much more efficient than linear circuits.
Use a ferroresonant transformer with a square-wave driving it.

dear audioguru,
do you have any suggestion to modify the circuit as u meant ??? the cost isnt a problem as i know you said before the ferroresonant transformer is expensive enough.....i just want to learn more about the inverter projects  ;D ;D ;D so after i can sucessful make it work so i can share to other ppl in this forum
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Hello everyone . I found a circuit to generate a modified sine wave. Can it be used with the inverter as an oscillator .

THe Opamp just filters the modified digital sine wave . so if you dis regard the opamp it gives a approximation sine wave or a modified sine wave , digital sine wave , whatever.

Both outputs are shown , with and without op amp

post-15126-14279143003114_thumb.jpg

post-15126-14279143003333_thumb.jpg

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Hello everyone . I found a circuit to generate a modified sine wave.

No. It isn't a modified sine-wave for an inverter, it is just a linear sine-wave with steps in it.

A modified sine-wave allows the output transistors to switch fully-on so there is not any voltage across them, or fully-off so there isn't any current in them. Therefore the power dissipation in the transistors is very low for good efficiency.
With many pulses per wave, Pulse-Width-Modulation is used like in a class-D amplifier to reduce power dissipation in the output transistors.

post-1706-14279143003532_thumb.png

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Now its your duty to explain it to all.

Hi Sasi,
I asked about the circuit you attached because you have made many more inverters and power supply circuits than me. Your circuits use that IC frequently but I have never seen that IC.

At 1st glance, I think the inverter has a square-wave output. But it might have a modified sine-wave with its voltage too low if the IC's "dead-time" can be long enough.
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