Hi Team,
1. My customer use INA199 in detect charging current.
Recently, during trial production, it is found that the IN + / IN- input has low impedance to the ground after charging.
Could you please check the schematic to see if anywhere needed to be modified?
ISO_5V = USB Adapter 5V/1A
CHARGER_5V = load current<90mA
2. If I use a USB charger and the load current is less than 80mA, do I need to add protection to the input terminal?
Thanks and best regards,
Jamie
Hi Jamie,
The partial schematic looks fine.
Low impedance to ground implies that the input pins are damaged, the first place I would look into is transient events. The datasheet devotes a section talking about this issue and potential pitfalls of A version devices in certain applications. Please refer to section 8.4.5 “Improving Transient Robustness”.
Particularly this paragraph:
It is recommend using B or C versions for this customer’s configuration. The issue should go away if the nature of the transients is similar to described, and no extra protection should be required.
Regards, Guang
