Other Parts Discussed in Thread: BQ24072,
Hi Experts,
Good day. I would like to ask confirmation about design help on your end for this case from client:
"1.) The concern in your response to case CS0746349 was that the device could break if the EN2 was tied to the input due to high voltage. But what if the EN2 pin is tied to the input using a pull-up resistor? Minimum voltage for a logic "1" is 1,4V according to datasheet. Let's say 2V to have some margin. With a standard 5V USB-charger as input, using a ~430kohm pull-up would create a 2V level on the EN2 pin together with the 285kohm pull-down, enough to set it high. With that setup, it would need an input voltage of ~17,5V before the voltage on the EN2 pin reaches the max limit of 7V. Would this setup be ok?
2.) Assuming the above is ok, and EN1 is pulled down. This would mean that with the USB-charger not attached to the circuit, EN2=low, EN1=low. If the USB-charger is connected, EN2=high, EN1=low. Would this cause any problems? Does the EN2/EN1 settings take action directly when changed?"
I understand the concern of the my customer here as they're not wanting to connect the EN2 pin to OUT since this would yield ~15uA current/power dissipation to internal pulldown (285kOhm) at 4.4Vout which is too high for low power application; thus they wanted it to be connected with lower signal to trigger HIGH logic. Datasheet shows input current source (HIGH) max of 10uA, but no minimum reading shared. Can you confirm if his turned voltage divider setup at EN2 pin would suffice? This voltage divider would give current flow ~3uA.
His 2nd question can be answered thru the graph shown at page 22 of its infosheet.
Thank you.
Regards
Archie A.
