Inquiry regarding Slope Compensation Detail on UCC28220-Q1

Hiroshi Doi35

Wallinger-san,

Thank you. But my customer give up too much tolerance of slope compensation.
He will do the compensation outside IC. And he asked me another question.
Is it no problem "Slope terminal #5 --> Open ( no resistor )" ?

Regards,

H.DOI

over 8 years ago

0 Karl Wallinger over 8 years ago

TI__Genius 16030 points

Doi-san,

I'm sorry for the delay. Please let me investigate this. At first glance, I wouldn't recommend leaving SLOPE pin floating, in case it is setting the PWM comparator input to an undefined level, or maybe susceptible to noise.

Regards,
Karl

0 Hiroshi Doi35 over 8 years ago in reply to Karl Wallinger

Expert 2845 points

Wallinger-san,

Please accept this way to stop Slope compensation.
Insert 1kohm and 0.01uF by series between SLOPE terminal and GND.
SLOPE connect 1kohm connect 0.01uF connect GND.
It's impedance is very low. And my customer checked CS, Slope OUT REF terminal
There is no oscillation and no problem .

Regards,UCC28220Slope.pdf

0 Karl Wallinger over 8 years ago in reply to Hiroshi Doi35

TI__Genius 16030 points

Hello Doi-san,

I'm glad you got it to work. I don't see any issue with your proposal, as long as the regulation is stable.

Regards,
Karl

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Inquiry regarding Slope Compensation Detail on UCC28220-Q1