How can I proportionally increase current draw from a load?

[doublec4]

Hi all,

I have a powered RFID tag that consumes very little current (~2mA). I would like to use a high side current sensor to read the current... however the load of the RFID tag is low compared to the range of the current sensor (let's say 1-10mA).

Is there a way to proportionally increase the current draw from the RFID tag to somewhere closer to the middle of the sensor range, ie. 5mA ?

So when I say proportionally increase, for example if the RFID tag current drops to 1mA, the current being seen by the current sensor would also drop by 1/2 to 2.5mA

Hope this isn't a silly question! I know another option is to change the R_sense of the current sensing device but if possible I would not like to try and modify the surface mount part if I do not have to.

Thank you

[ledtester]

How about use a current sensor with a programmable gain amplifier? For instance, the INA219 can be programmed for /1, /2, /4 or /8 gain.


Nice summary of current sense modules commonly used with microcontrollers:

https://youtu.be/cG8moaufmQs

[S. Petrukhin]

No amount of persuasion and arrangement can get more current consumption from RFID, you will have to change the circuit. Maybe you will be satisfied with a parallel shift of the current consumed to the sensor's sensitive area by simply installing a resistor in parallel with the RFID power?

[David Hess]

Either offset the current by adding another fixed current through the current sensor or multiply the current, which can be done with a current mirror.