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Original question:

UCD9248: UCD9248

UCD9248: UCD9248

MaWü
Prodigy 220 points
Part Number: UCD9248
Other Parts Discussed in Thread: UCD7242

Hello TI engineers,

the setup is a UCD9248 controlling 2x UCD7242 with 4 rails in total.

I have trouble with the Fusion Digital Power Designr GUI:

In System Monitor is an orange Power_Good warning and all 4 rails have green status. PG thresholds are at -10% and -20 %.

Also in the Configuration window under Monitor, under Status Register/Lines, under Misc is an orange warning “Output Off, Power_Goood#” and SMBalert is asserted.

Any idea what could be the reason that for all rails Vout is down?

Thx in advcance 

MW

  • 0
    TI__Expert 5965 points

    Hi MaWu,

    Can you provide more details on how you enable the rails? From what you describe, it looks the rails have not been turned on yet.

    Regards,

    Weidong

  • 0 in reply to Weidong Zhu
    Prodigy 220 points

    Hi Weidong,

    I have 2 controllers and 4 rails as followed.

    Method to enable: Operation, command ON/OFF

     

    #1 3V3, Irated 3A --> running

    #2 3V3 , Irated 150mA --> CLF

    #3 0V8, Irated 2.5A --> running

    #4 3V3 , Irated 150mA --> CLF

     

    #1 3V3, Irated 100mA --> running

    #2 1V2 , Irated 400mA --> running

    #3 3V3, Irated 100mA --> CLF

    #4 1V8 , Irated 20mA --> TON_MAX Fault; UCF; OCF (OCW warning)

     

    Could it be that the small rated currents causing problems?

    What Iout limits would you recommend to set, resp. using the “set” button referring to the rated current value?

    BR MW

     

     

  • 0 in reply to MaWü
    TI__Expert 5965 points

    Hi MaWu,

    The current sense circuitry of UCD7242 can not support accuracy down to mA level. I would suggest you use higher current limit.

    Regards,

    Weidong