UC2844 as Gate Driver

Takahiro Nishizawa

Genius 5575 points

Other Parts Discussed in Thread: UC2844

Please check the attached document.

We use UC2844 as Gate Driver.

We want to fix the frequency(50kHz) and Duty(25%).

We think that This IC can fix the duty cycle if we connect VFB pin and VREF pin. Because voltage of Vref is 5V fixed.

So It is not affected by voltage fluctuation.

Please tell us the value of R1 and R2 when Duty is 25%.

Best regards,

Takahiro Nishizawa

Question of UC2844.pdf

over 7 years ago

0 Peter Meaney over 7 years ago

TI__Mastermind 31580 points

UC384x VM.pdfHi Takahiro-san,

I have attached a marked up diagram that should get close to the application requirement.

Regards

Peter

0 Peter Meaney over 7 years ago in reply to Peter Meaney

TI__Mastermind 31580 points

Hi Takahiro-san

Since there has been no activity on this post for two weeks I am closing the post. Please open a new post if you have more questions.

Regards

Peter

0 Takahiro Nishizawa over 6 years ago in reply to Peter Meaney

Genius 5575 points

Thank you for your support!

We don't use VFB pin.
We use Dividing resistance between VREF pin and COMP pin.
We supply bias voltage to COMP pin.
But Duty cycle changes at a stretch from 2% to 50% when DC bias voltage increases.
Duty cycle can not be increased step by step.
We want to set 20% duty fixed.

Do you know the cause?
Please tell us the method that we set the duty cycle.

Best regards,

Takahiro Nishizawa

0 Takahiro Nishizawa over 6 years ago in reply to Takahiro Nishizawa

Genius 5575 points

Thank you for your support!

How about your situation?
We are waiting for your answer bout these questions.

We don't use VFB pin.
We use Dividing resistance between VREF pin and COMP pin.
We supply bias voltage to COMP pin.
But Duty cycle changes at a stretch from 2% to 50% when DC bias voltage increases.
Duty cycle can not be increased step by step.
We want to set 20% duty fixed.

Do you know the cause?
Please tell us the method that we set the duty cycle.

Best regards,

Takahiro Nishizawa

0 Peter Meaney over 6 years ago in reply to Takahiro Nishizawa

TI__Mastermind 31580 points

Hi Takahiro-san,

I am going to close this post as I believe we are discussing this question on another post.

Regards

Peter

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UC2844 as Gate Driver