TPS3813: TPS3813K33DBVR

Akshay,

It seems by looking at your schematic that you are trying to program the window-watchdog using an external capacitor as described in section 8.5.2 of the datasheet. If this is the case, using your 180 pF capacitor at C73, you should not have it also connected to Vdd at WDT. The operation modes are either to ground, to Vdd, or to an external capacitor. Additionally, if you choose to use a programmed option, you must connect WDR to either GND or Vdd depending on what you want your lower window frame to be. Let me know if you need more help on the subject.

Thanks,
Abhinav.

Hello Abhinav,

My application requires 2 seconds of timer, so can you suggest what should be done in this as currently I have given every provision possible by using DNP in my schematic so as to not get stuck later if either of the case don't work.

Also let me know if i will have to change the capacitor value so as to get the 2 seconds in this application.

Thanks&Regards

Akshay Pathak

Dear Abhinav,

Thank you for your quick response and sorry for the delay.

I got this part num and tested it externally with my device and I have some query regarding this.
As i was testing when I give supply to this IC then it generates one reset in starting itself and it doesn't let my device wake up from standby mode (as in standby mode my device won't be sending any data to WDI pin of this IC) from the very starting.
It's because it generates one reset in the very starting when i try to wake up my device.

So can you suggest what steps should i take so as to resolve this thing and move forward in my application.

Thanks&Regards
Akshay Pathak

Akshay,

I'm a little confused by your wording. Are you saying that you are trying to generate a reset immediately or that you don't want a reset to be generated immediately? Could you clarify?

Thanks,
Abhinav.

Dear Abhinav,

I apologize if I created any confusion, what i wanted to say is that my device is not waking up as watchdog timer IC resets it in the starting.

I have controlled the supply of watchdog using Mosfet and i am driving it with my MCU as shown in the below image.

So whenever i wake up my device and Watchdog gets its supply then it generates reset function in the starting and my device again goes into standby mode, which is a problem as it won't let my device come into normal mode.

So i need your support about what should be done.

I hope this clarifies the confusion.

Thanks&Regards

Akshay Pathak

Akshay,

Is your RESET going high and then dropping low? Do you have any scope shots I could see to diagnose why you're encountering this? I'm still a bit unclear on the events. If your RESET is not staying high, it is most likely an issue with the application circuit, but I need a little help understanding what is happening now and what you are trying to accomplish. Scope shots would be very helpful.

Thanks,
Abhinav.