Part Number: tps386000
My customer meet an issue of TPS386000: as it`s timer will enable after power on or reset, but their processor will take long time(>10S) to start up, or they need to download firmware some time, thus need long than 10S, but at these condition, TPS386000 will output WDO to reset the processor, so do we have solution to fix this issue?
As i know lots of other supervisor device will need to triggle the time after power on, i don`t know why TPS386000 enable timer automaticly after power on.
Thanks very much.
The TPS386000 timer will automatically be enable once the SENSE inputs are above their threshold voltages and the /MR signal is high, which I assume is happening with the customer's application. Is there a signal that the customer can use to pull /MR low or pull WDI high during start-up?
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In reply to Ben Chan:
Any feedback from the customer? I wanted to follow up with you on this particular application. At this time, there is not a product within our portfolio that has this level of integration and performance like the TPS386000.
Many thanks for your comments, so do you mean if customer pull MR low or WDI high will prevent reset signal generated? if so i think we can ask customer to add another signal.
In reply to Sunny Qin:
I am not sure if my suggestion will work. I just realize that /MR only affects input #1 and not all of the other inputs. Let me get back to you so I can give you the correct answer for your customer.
Thanks for comments, I also found that pull low MR may can not precent reset signal happen.
As customer`s processor need tens of second srart up time, so customer need a solution that TPS386000 not output reset signal during start up. Add a MUX between processor`s reset pin and WDO(use another signal to control the MUX) do can fix the issue, but this is too complex for customer.
Pull WDI high you mentioned will be a quite good solution, but i can`t find any description on datasheet, so may need you confrim on that.
Has the customer committed to use the TPS386000? The other option is to use individual voltage supervisors (TPS3851) with programmable delay. Pulling up on WDI will not work as I was looking at the wrong waveform and misspoke. I apologize for giving the wrong information.
customer can only choose TPS386000 as it`s the only AVL in customer. Do you mean we have no way to prevent reset signal happend duiring processor`s long start up time?
If so i wll try to ask cusotmer add an external MUX.
Unfortunately, there is not a way to prevent the RESET signal on the TPS386000 from RESET'ing once it is operating.
You can suggest to the customer to mux a signal into the WDI pin to prevent the output of /WDO to reset during startup.
Got it, many thanks for commetns.
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