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UCD9081: Power sequence up/down

Shay Mor
Intellectual 870 points
Part Number: UCD9081

Hi,

I want to use ucd9081 for power up and down 2 devices. which device are using 4 EN and 4 MON separately. 

device_1 (MON1,MON2,MON3,MON4,EN1,EN2,EN3,EN4) device_2(MON5,MON6,MON7,MON8,EN5,EN6,EN7,EN8)

my Q is: if I what to shutdown only 1 device for example device_1 with save the right power sequence down without using I2C register, can I? (while the other device_2 keep alive)

  • 0
    TI__Guru 65700 points

    Hello

    UCD9081 is used to control two different power groups. Most time the power down sequencing is trigger by fault. when a fault is detected, device can shutdown rails based on how they are configured. For example. if MON1 has UV/OV fault, you can configure to shutdown EN 1/2/3/4, but let EN 5/6/7/8 stay.

    if there is no fault, you have to use I2c to turn off the rails.

    Regards

    Yihe

     

  • 0 in reply to yihe
    Intellectual 870 points

    thank,

    if I have the following sequence:

    EN1->EN2->EN3->EN4

    and

    EN5->EN6->EN7->EN8

    where should I put the 2 FATs for fault? on MON1 and MON5 or MON4 and MON8?

    if I put the FAT on MON1 could I sequence down like: EN4->EN3->EN2->EN1 or EN1->EN4->EN3->EN2 ?

  • 0 in reply to Shay Mor
    TI__Guru 65700 points

    Hi

    It is better to put FATs on all  rails since any rail could have a fault during the runtime.

    You have to set different shutdown delay on rails respectively so that the EN will be off based on the delay.

    Regards

    Yihe