UCC28C45-EP: RC Circuit

Ray Vincent Aranzaso

Part Number: UCC28C45-EP

Hi,

Good Day.

On the component datasheet, an example application schematic (sheets 9 & 10 – Figure 4) shows an RC circuit (see circled in red below) implemented between the Current Sense pin (#3) and the Primary of Transformer T1.

The customer is using the UCC28C45MDREP in a circuit without this RC and is nothing an inconsistent charging current.

What is the design intent of this RC network on the CS pin?
Are we damaging the PWM controller without this RC network in our device?

Please advise. Thank you very much.

Best Regards,

Ray Vincent

over 2 years ago

0 Sean Xu over 2 years ago

TI__Genius 14580 points

Hello,

R/C provides leading edge blanking to remove the current spike when the power MOSFET is turned on. Without R/C, the switch could be triggered by the switching spike.

0 Ray Vincent Aranzaso over 2 years ago in reply to Sean Xu

TI__Genius 15675 points

Hi Sean,

Good Day. Please confirm, does the "could be triggered" means that "after on state, the initial current spike on CS, pin3 could trigger the MOSFET to an "off state"?

Best Regards,

Ray Vincent

0 Sean Xu over 2 years ago in reply to Ray Vincent Aranzaso

TI__Genius 14580 points

Yes, that is correct.

Power management

Power management forum

UCC28C45-EP: RC Circuit