Hello,

i want to simulate a push pull converter to check my knowledge. So i came up with the circuit from the internet.
The green plot on the image is the voltage on the inductor which doesnt make much sene to me. What i was expecting is
a voltage on the inductor between -6V to 6V (PWM type of signal). Can anybody help me with this stuff?
What i also noticed is the voltage between the 2 capactiors is not 6V instead it seems like one capacitor is getting 9V and the other one only 3V. Why is that? The two capacitors form a voltage divider and they re equal....

Any hints or working simulations for me? Or a design tutorial with calculations?

I have also checked the pulses of the gates and they are 180° shifted in phase, so that only one of the transistors is turned on, then the other and the cycle repeats.

pleaseee thank u

 

The upper Mosfet is a follower that needs its gate pulse voltage to be at least 4.5V higher than the supply voltage.
A voltage converter uses "bootstrapping" with a capacitor and a diode to obtain that boosted gate voltage.

 

What is the purpose of the two capacitors?
If you want to block DC to the transformer, then just use a single capacitor between the push-pull output and one transformer input with the other transformer input to ground.

 

The upper Mosfet is a follower that needs its gate pulse voltage to be at least 4.5V higher than the supply voltage.
A voltage converter uses "bootstrapping" with a capacitor and a diode to obtain that boosted gate voltage.

My god, how could I miss that. Thank you so much.

What is the purpose of the two capacitors?
If you want to block DC to the transformer, then just use a single capacitor between the push-pull output and one transformer input with the other transformer input to ground.

The two caps form a capactive voltage divider. So what i get is 6V between them since they equal.


Seems to be working now. Im getting what I was expecting.

 

See

 

The two caps form a capactive voltage divider. So what i get is 6V between them since they equal.

But you don't need two caps.
One cap in series with the transformer is all that's required.