UCC28064A: maximum switching frequency

Shubiao Wang

Part Number: UCC28064A

Hi,

I want to know that is there a limiting value of maximum switching frequency for UCC28064A, no matter in any unexpected condition.

for example, the FAN9611 has a maximum fsw shown in its datasheet.

Best regards!

Shubiao Wang

over 6 years ago

0 Eric Faraci over 6 years ago

TI__Expert 8210 points

Shubiao

In the UCC28064A datasheet on page 8 the minimum switching period is specified at 2.7 us typical. The inverse of this is the maximum switching frequency, which is slightly above 370 kHz.

Best Regards,

Eric

0 Shubiao Wang over 6 years ago in reply to Eric Faraci

TI__Intellectual 1490 points

Thanks Eric,

What about the minimum fsw?

the max FET on time at high VINAC, tonmax_H= 2us, considering the duty cycle D=(Vout-sqrt(2)*VINmax)/Vout=(390-264*1.414)/390=4.27%, so the min fsw at high VINAC is 21.3kHz.

the max FET on time at low VINAC, tonmax_L=20.4us, D=(390-85*1.414)/ 390=69.2%, so the min fsw at low VINAC is about 33.9kHz.

So the min fsw that ucc28064A support is 21.3kHz, does it right?

Best regards,
Shubiao

0 Eric Faraci over 6 years ago in reply to Shubiao Wang

TI__Expert 8210 points

Shubiao

Minimum switching frequency is set by parameter t_START.

So fswmin=1/t_START = 4.762kHz Typ value.

Best Regards,

Eric

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UCC28064A: maximum switching frequency