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INA310A: Adjustable High-side Current source

Part Number: INA310A
Other Parts Discussed in Thread: INA190, INA293, INA301

Hello,

I want to drive 3 resistive loads with controllable current source:

  • R1 = 6.5R; V1_max = 13V; I1_max = 2A
  • R2 = 11R; V2_max = 14.3V; I2_max = 1.3A
  • R3 = 400R; V3_max = 96V; I3_max = 0.25A

These are my inputs:

  • V_in = +12V
  • V_control = 0..2,5V (from DAC)

I can boost the +12V to +15V@4A (for R1 and R2) and +100V@0.3A (for R3).

Can you suggest the adjustable current source that can drive these 3 resistive loads?

I can build 3 separate current sources for these, that's no problem. It will be best if they use the same IC.

Ideally, they should be driven using high-side sensing, i.e with this INA310 (so that 1 pin of the load goes to ground).

Thank you very much in advance.

Best Regards,

  • Hello Takuchi,

    I am looking this over and will respond shortly.

    Best,

    Peter

  • Hello Takuchi,

    You could do something like this, where you have an op amp controlling a FET based upon feedback from a high-side shunt amplified by CSA (e.g., INA310):

    In this example, DAC_OUT is the controlling voltage which sets the current.

    This example is for an extremely slow application, hence the large R,C's and the INA190 is not a great option for fast feedback, which is why R2 and C9 are so large. You could directly replace INA190 with INA310.

    The INA310 model is still being developed, but should be done in about a month. If you want to simulate now, you could use the similar INA293 in its place, but you would not have the comparator function yet.

    There are plenty of circuits we have on our website that can be adapted similarly where feedback is from a CSA on the high-side.

    https://www.ti.com/sitesearch/en-us/docs/universalsearch.tsp?langPref=en-US&searchTerm=current%20source&nr=98276#q=current%20source&numberOfResults=25

    Sincerely,

    Peter

  • Hello Peter,

    Thank you very much for your answer. 
    Do you have any other options that's faster than the INA190 or INA310?

    Can this MOSFET CSD18534 work at my +100V application?
    Thank you very much in advance.

    Best Regards,

    Takuchi

  • Hello Takuchi,

    The only other faster amplifier we have is the INA296. The INA301 is comparable in overall comparator trip speed.

    The CSD18534 is a 60-V device. You have to search for >100V FETs.

    As for the op amp, you would want one with a unity gain bandwidth that is similar or greater than the closed-loop BW of the current sense amplifier.

    Sincerely,

    Peter