low-side measurements disadvantage

Hi Takao-san,

High-side measurement:

If the load is shorted like on the schematic above, the current through the short which is the same through the resistor will increase a lot and will be detected by the INA part.

Low-side measurement:

If the load is shorted on the schematic above, the current go through the short and nothing goes through the load and then the Rshunt. The sensing part is then not able to detect if there is a short or just no current consumed.

Best regards,

Aymeric Nicolas

Dear Aymeric,

Thank you for your answer.

However the short situation is different between Hi-side and Low-side.

I could understand Hi-side case.

Should we think like following about Low-side?

When the load is shorted like above, can the sensing part detect?

If it can do that, Low-side measurement has the same advantage to detect fault as Hi-side measurement.

Best regards,

Hi Takao-san,

For my first post the two situations show a "short to ground". In that case only the high-side sensor is able to detect it.

On your example you have a "load shorted". In a certain way the "short to ground" in the high-side configuration is also equivalent to a "load shorted".

In the case of a "load shorted" you can indeed detect it in both cases. For the high-side it's the same reason that explain above and for the low-side it's because in case of a "load shorted" the voltage to the pin+ will increase from a really small value to the value of the power supply. Then the output will basically rail up.

Best regards,

Aymeric Nicolas