How to improve duty cycle in an oscillator at 1 MHz?

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hebu

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Improve duty cycle

I have an oscillator running at 1MHz, any method to improve the duty cycle
to 50%?
 

Re: Improve duty cycle

to set the VLT of oscillator to Vdd/2, and set the charge and discharge current of the ring/gate to the same. Or you can use a buffer to modulate the duty.
 

Re: Improve duty cycle

You can make a oscillator with 2Mhz ,
This signal devide by 2 with digital divider (1/2).(with Flip-flop )
This you can get 1Mhz 50% duty cycle signal.
 

Re: Improve duty cycle

tsanlee said:
You can make a oscillator with 2Mhz ,
This signal devide by 2 with digital divider (1/2).(with Flip-flop )
This you can get 1Mhz 50% duty cycle signal.

this is a standard solution and work very well
 

Re: Improve duty cycle

Ya, thanks guys, I know we can obtain 50% duty cycle by divide by two.
But now, 2MHz is not avaliable, so I would like to know any popular
method to get 50% duty cycle?
 

Re: Improve duty cycle

Calaulate the time btw clock "H" and "L" period by RC structure, and comparing by
each cycle. adjusting duty cycle by one step(maybe xxns) depend on the result above. continue first step.
 

Re: Improve duty cycle

Generate a short pulse (impulse) for each rising and falling edge. You have then effectively doubled the frequency. Now you can divide/2 to get your 50% duty cycle. It is easy to make an edge detector with RC and inverter gate. Then OR the pulses from 2 gates to get the X2 output for the F/F.
 

Re: Improve duty cycle

hebu said:
Ya, thanks guys, I know we can obtain 50% duty cycle by divide by two.
But now, 2MHz is not avaliable, so I would like to know any popular
method to get 50% duty cycle?

It depends on your circuit. Can you show your circuit here?
 

Re: Improve duty cycle

using DLL or PLL
 

Re: Improve duty cycle

Btrend said:
using DLL or PLL

I can't realize why PLL can control the duty cycle?
 

Re: Improve duty cycle

PLL didn't control the duty cycle, but instead it will give u 2*f clock which is only depent on the rising edge of ur input clock.
By doing this, u can do a div by 2 to get exactly 50% duty cycle.
 

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