I am trying to sense very low current (50 - 200 uA) on the high side of a circuit, and was considering LTC6102HV for the job since it can be "floated" to 105 V.
My problem however is that my circuit is not floated to +105 V but to -105 V and the current does not flow to the ground. if I understand it right, I cannot use LTC6102HV.
Here's a picture that illustrates the problem, I am trying to measure I_sense, across R_sense.
I can probably just use a diff amp (e.g. AD629), but since I am measuring microamps, I am not sure if it is the right way to do it.