UCC2806 Soft Start functionnality

Jean-Jacques Avenel

Other Parts Discussed in Thread: UCC2806, UC2846

Hi, on UCC2806 there's no specific soft start pin, is it possible to realize this function with external components please ?

UC2846 seems very similar to UCC2806 and we can see page 10 of UC2846 DS an example of soft start function with a simple capacitor in // with resistor divider connected on pin1 (current limit adjust). Is it possible to do it with UCC2806 ?

Moreover in free running mode, saw signal on RT pin is used to generate a slope compensation. But if part used with an external clock on Sync pin, this RT pin does'nt generate saw signal anymore, so how to generate a slope compensation signal ?

Thanks in advance for your support.

over 12 years ago

0 cristian naranjo over 12 years ago

Prodigy 10 points

hi, i don´t speak good english but..; you can to used the capacitor for soft start in the pin Vref, with this, the referent voltage increase slowly, you can to calculate this how a RC netwok the time that you need for a good soft start is around to 10-100ms, the resistor are the divisor to Vref, you anly need to calculate the capacitor. the anoter question don´t undertand so good .

0 Praveen Desireddy over 12 years ago in reply to cristian naranjo

Prodigy 70 points

I could not find a pspice model for UCC2806 on TI website. Does anybody know how to get it?

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UCC2806 Soft Start functionnality