UC2842: Formula

Ray Vincent Aranzaso

Mastermind 18180 points

Part Number: UC2842

Hi,

Good Day.

1. What formula to calculate Vbulk (min)? Please provide the formula.

2. "Lm is inductance you chose", so it is 1.8mH or 1.5mH which is Lp. Why don't we say Lp but change the term to Lm?

Please advise. Thank you very much.

Best Regards,

Ray Vincent

over 3 years ago

0 Jerry Xu over 3 years ago

TI__Expert 3160 points

Hi,

(1) Vbulk (min) is the minimum value of input voltage. The typical value is 85V/AC. If you want to look for the formula of calculating bulky cap. Here is the reference.

(2) Lm and Lp represent transformer inductance. It's all right.

Jerry Xu

0 Tuyen Le over 3 years ago in reply to Jerry Xu

Prodigy 20 points

Hi Jerry,

I am confused. You said the typical value of Vbulk(min) is 85A/AC but Vbulk=75 is used in the example calculation. Did I miss some points here?

0 Jerry Xu over 3 years ago in reply to Tuyen Le

TI__Expert 3160 points

85V/AC is the peak value of input AC voltage. In bulky cap, the minimum value will be determined by bulky cap. Because the minimum value is rectified.

0 Tuyen Le over 3 years ago in reply to Jerry Xu

Prodigy 20 points

Thank you. It is clear now.

0 Jerry Xu over 3 years ago in reply to Tuyen Le

TI__Expert 3160 points

I will close this thread.

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UC2842: Formula