UC3843: Compensation clculation

ALINA NAZ

Prodigy 30 points

Part Number: UC3843

I am making a non-synchronous buck converter.

Vin=400-840V

Vout=320V

Pout=4.4kW

I want to use a simple PWM IC for this circuit. UCx84x looks like a good solution, but I am confused how to calculate the compensation R and C for this circuit.

Is there any direct formula or if can you guide me on the design method?

over 2 years ago

0 Joseph Conrad over 2 years ago

TI__Expert 7860 points

Hi Alina,

I would recommend you look at the Power Stage Designer tool: POWERSTAGE-DESIGNER Design tool | TI.com

It has a module that can help calculate the component values based on loop characteristics and your system specifications.

Thanks,

Joseph

0 ALINA NAZ over 2 years ago in reply to Joseph Conrad

Prodigy 30 points

Thank you. I used the design tool and got the compensation values but it seems that I am not able to get the switch to work with the IC.

I am not sure how to fix this.

0 Joseph Conrad over 2 years ago in reply to ALINA NAZ

TI__Expert 7860 points

Hi Alina,

It looks you're using a non-TI device in this simulation (LT1242) which I can't support. I would recommend using the UC3843 PSPICE model to simulate the device and see its performance with your compensation values. We have a free PSPICE for TI software that you can download and run simulations.

Thanks,

Joseph

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UC3843: Compensation clculation