Is there a way of turning a square wave signal of any duty cycle to a square wave with a 50% duty cycle (and same frequency)?

I'm trying to make a self-oscillating tesla coil driven with a PWM signal with a duty cycle of 50%. The PWM signal drives a full-bridge inverter, while the feedback signal is obtained via an antenna. But the feedback signal I receive doesn't have the same duty cycle. Is there a way of changing its duty cycle to 50% to drive the tesla coil?


For example, shown above in green is the actual signal I need to drive the tesla coil. The signal in red is the feedback signal I'm receiving.

I've also attached the ltspice simulation for clarity.

 

Is the feedback signal frequency fixed (albeit with varying duty cycle)? If so you could frequency-double it, then use the doubled frequency to clock a toggling latch to get back the original frequency with 50% duty cycle.

 

You could divde the frequency by 2 (toggle on one of the flanks) and then use a PLL to double the frequency.
The output of the PLL should be your desired frequency with a 50% duty cycle

 

you could frequency-double it

How would you do that so the output FF gives a 50% duty-cycle?

 

You could divde the frequency by 2 (toggle on one of the flanks) and then use a PLL to double the frequency.

Why half the frequency?
I would think the PLL would operate with the PWM signal as is for its input.

 

How would you do that

PLL if the frequency is not fixed. But if the feedback signal is a fixed known value then a simple pulse generator could do the job.

 

I'm trying to make a self-oscillating tesla coil driven with a PWM signal with a duty cycle of 50%

Why?

What is the oscillator frequency and the driving frequency? Are they related?

 

Why half the frequency?
I would think the PLL would operate with the PWM signal as is for its input.

Most PLLs need a duty cycle of 40-60%.

 

Why?

What is the oscillator frequency and the driving frequency? Are they related?

The oscillator frequency is the self resonance frequency of the tesla coil. The driving frequency should be equal to the self resonance frequency in this case.

 

Then it is not self oscillating. A self-oscillating coil would not be driven another oscillator, it would be part of the oscillator circuit.

Can you explain why you would drive it with a square wave at its resonant frequency? That does not sound right to me.

A traditional Tesla coil is driven by a sharp pulse (capacitor discharging through a spark gap) at a much lower frequency than the resonance.

 

Then it is not self oscillating. A self-oscillating coil would not be driven another oscillator, it would be part of the oscillator circuit.

Can you explain why you would drive it with a square wave at its resonant frequency? That does not sound right to me.

A traditional Tesla coil is driven by a sharp pulse (capacitor discharging through a spark gap) at a much lower frequency than the resonance.

You can drive a tesla coil without the capacitor, but you need to know the resonance frequency.