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UCD90160: Timeout usage on GPI used as "PGOOD" signal

Other Parts Discussed in Thread: UCD90160

Hello,

I use a power sequencer UCD90160 to switch on/off many power supplies. Due to the high number of monitored power supplies, the UCD90160 analog inputs are not sufficient to monitor all voltages. So, two of the voltages are sequenced by the UCD90160 using their « enable » and « PGOOD » signals. 

I want to realize the following power-on sequence:

  1. Wait for Main powers presents
  2. 3V3 -> 1V0 -> 1V8 -> 1V5 -> 1V2
  3. 1V8_0 (activate 1V8_0_EN with GPIO8) and 1V8_1 (activate 1V8_1_EN with GPIO7)
  4. Start 1V025 as soon as 1V8_0_PGOOD and 1V8_1_PGOOD are ‘1’
  5. 1V35

My project works fine, and the power-on sequence is correct. Nevertheless, this configuration doesn’t control the switch-off in case of 1V8_x rise issue. Indeed, I had activated the “GPI Seq on dependencies” for 1V025 rail, in order to wait for 1V8_x_PGOOD signals.

But if one (or more) of the 1V8_x power supplies doesn’t rise, its associated PGOOD signal doesn’t goes high and the startup sequence stops, waiting for this signal. In this case, the board is partially powered, with 1V025 and 1V35 off.

So, I’d like to add a timeout on 1V8_x_PGOOD rise. This can be easily performed using the “Max turn-on delay” when the power supply is monitored by an analog input, but I can’t do the same using a logic input (my PGOOD signal). Nevertheless, it seems to be possible when reading the UCD datasheet (DLVSAC8A - rev Apr 2011 - page 22)

=> How could it be performed ?

 Best regards,