UC2525A: SYNC

Martin Wen

Part Number: UC2525A

Hi Bros,

My customer is using UC2525A to design 5 channel half bridge power which using sync function. For the first UC2525A, it is in master mode. Change the R27, the frequency can change from 800Hz to 1.5KHz.

For the other UC2525As, they are in slave mode.

During testing, we found the slave frequency cannot always the same as the master especially when the master frequency is higher than 1.35KHz. I cannot find anything relationship between the sync frequency and RT,CT frequency. Do we have anything equation to set the slave UC2525A's RT, CT, RD in OSC mode? Thanks.

over 8 years ago

0 Martin Wen over 8 years ago

TI__Prodigy 615 points

Sorry for the mistake of master mode sch.

0 Peter Meaney over 8 years ago in reply to Martin Wen

TI__Mastermind 31580 points

Hi Martin,

I have asked one of our applications engineers to respond to your post. Your should see a reply later today.

Thanks

Peter

0 Oliver Pan91 over 8 years ago in reply to Martin Wen

TI__Intellectual 2230 points

Hi Martin,

Usually, the oscillator frequency of slave should be around 90% of that of the master. Please see more information in this post:
e2e.ti.com/.../522755

Best Regards
Oliver

0 Martin Wen over 8 years ago in reply to Oliver Pan91

TI__Prodigy 615 points

Hi Oliver,

Thanks for the answers. So if the master frequency is changed by variable resistor, it is impossible to using OSC output function? Thanks.

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UC2525A: SYNC