TPS3823: DO you know what meaning " RESET is stuck at a logic low......"?

Eggsy Pang

Part Number: TPS3823
Other Parts Discussed in Thread: TPS3820, , TPS3828, TPS3824

Hi team，

from the dataseet， customers sea below "

In applications where the input to the WDI pin is active (transitioning high and low) and the TPS3820, TPS3823,
TPS3824, or TPS3828 is asserting RESET, RESET is stuck at a logic low after the input voltage returns above
VIT–.

DO you know what meaning is?

over 5 years ago

0 Michael_DeSando over 5 years ago

TI__Genius 12630 points

Hi Eggsy,

The meaning is when RESET occurs and goes logic low, if WDI signal arrives on WDI pin, RESET stays low even if VDD rises above threshold. The RESET output latches and remains low. If you do not want this latching type, then please use version A or use the external transistor such as MOSFET to keep WDI signal from arriving on WDI pin when RESET is active and logic low.

Please let me know if this is clear or if you have more questions. Thanks!

-Michael

0 Eggsy Pang over 5 years ago in reply to Michael_DeSando

TI__Expert 4985 points

Hi Michael,

You said " if WDI signal arrives on WDI pin, RESET stays low". May I know what WDI signal is like? Square wave? or just logic high? or just logic low?

0 Michael_DeSando over 5 years ago in reply to Eggsy Pang

TI__Genius 12630 points

Hi Eggsy,

To answer your question, the WDI signal is a pulsing signal with the rising or falling edge arriving within the watchdog timeout. If the WDI is pulsing while /RESET is active and logic low, the /RESET will latch even if VDD rises above the under voltage threshold. You can choose the A version if you do not want latching behavior or you can use a decoupling MOSFET as the datasheet mentions.

Please let me know if you have any more questions or if this is unclear. Thanks!

-Michael

0 Eggsy Pang over 5 years ago in reply to Michael_DeSando

TI__Expert 4985 points

Hi Michael,

Thanks! If the /RESET latch, how to make the RESET come back to high logic ?

0 Michael_DeSando over 5 years ago in reply to Eggsy Pang

TI__Genius 12630 points

Eggsy,

You have to restart the device. This would be best for safety applications that require the user to investigate the issue before allowing the device to operate again. If you do not want the latch version, please user device version A

-Michael

Power management

Power management forum

TPS3823: DO you know what meaning " RESET is stuck at a logic low......"?