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UCC28950: How to shutdown UCC28950 PWM output by SYNC?

Vincent Li00
Intellectual 2035 points
Part Number: UCC28950

Hi Guys

UCC28950 configured as Slave mode, suddenly interrupt its SYNC (Pin 16) pin PWM signal during its operation, can it immediately turn off the UCC28950 drive signals OUTA, OUTB, OUTC...? 

If we want to immediately turn off /disable drive signals such as OUTA, OUTB, OUTC, etc., which pins can be controlled?

Thanks

-Pengfei

  • 0
    TI__Mastermind 25570 points

    Hello Pengfei

    The best, and correct, way to stop the UCC28950 from switching is to pull the SS/EN pin below its turn-off threshold at 500mV nominal (250mV min) using Q217A in your schematic. This will immediately, and asychronously set all OUTx signals to 0V within about 1us.

    If the SYNC signal to a Slave controller stops while at 0V then the controller will continue switching at its free running frequency set by the resistor at RT. Note that if the SYNC signal stops while HI, the OUTx signals will remain in whatever state they were at - you can expect power stage damage if this happens.

    Regards
    Colin