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UCC28061: UCC28061

xiaojun sun
Prodigy 50 points
Part Number: UCC28061
Other Parts Discussed in Thread: UCC28063

Dear

i have used UCC28061 to design a PFC with about 600W. the design parametre is same as the application of 600W PFC design.

Now i have a trouble that there are much interference caused by CS protection. there are much noise on the CS pin, so the PFC are protected just like hiccup. ( the driver's duty cycle is small and big), so there are more interference for other circuti.

could you give some suggestion how to improve it? i need the CS protect normally.

i have tried to added the RC filter on the CS pin.

My email is sxjbiti@163.com

best regards

sun xiaojun

  • 0
    TI__Mastermind 34465 points

    Hello sun xiaojun

    The UCC28061 is a transition mode controller and 600W is above its optimum power capability.

    At this power level the switching currents are going to be pretty high and you can expect large amounts of dI/dt induced noise.

    The CS pin is an overcurrent detection input to the UCC28061 and it has a very low trip level (200mV) .

    This makes the pcb layout very important in high power applications.

    A few things you should check:

    1. Do you have the Rsense value correctly calculated ?
    2. Do you have an RC filter on the CS pin as detailed in the reference applications
    3. Consider using the UCC28063. This is pin for pin compatible with the UCC28061 and it has a 100nS blanking on the overcurrent detection

    Regards

    John

  • 0 in reply to John Griffin1
    Prodigy 50 points
    Dear John
    1 the Rsense is 5mOhm, it's just refered the application
    2 the RC filter is 100Ohm 10nf
    3 i will tried the UCC28063, hope it works

    i think the noise caused by my layout, but it's have no time to redesign it later

    thanks