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TPS92515: Regarding constant current feature with IADJ pin.

Jagdish Karamchandani
Expert 1420 points
Part Number: TPS92515

Hello TI support,

We intend to use TPS92515 in an constant current application with load of 156mH & 50 ohms (coil).

1. Can we use IADJ pin to set constant current of 250mA ? Or that pin can only be used to control max current & hence used in  protection?

2. Also will it be feasible to set 250mA with 10% ripple current in load?

Regards,

jagdish

  • 0
    TI__Genius 16180 points

    Hi, Jagdish, 

    What is the load target application? It takes up to 300S to charge 156mH inductive load to 250mA with 12V constant voltage.  

    1. Yes, you can adjust IADJ to set constant current of 250mA. If you need accurate output current, you might need to calibrate it, or consider other device like TPS92643. 

    2. Yes. You can. You may increase output capacitance and reduce ripple current in load accordingly.  

    However, please check my question above first. I'd like to make sure the load is correct and you can select TPS92515 for this application. 

  • 0 in reply to Xiaoguang
    Expert 1420 points

    Hello Xiaoguang,

    1. Our application is of electromagnetic flowmeter having coil resistance of 50 ohm and inductance of 150mH. It needs to be excited by constant current of 250mA. Will it be suitable for this load?

    Also what shall be accuracy difference between TPS92515 and TPS92643?

    2. OK, 

    Please let us know the suitability of TPS92515 or similar IC for our application.

    Regards

    Jagdish 

  • 0 in reply to Jagdish Karamchandani
    TI__Genius 16180 points

    Hi, Jagdish, 

    Frankly, I'm not familiar with electromagnetic flowmeter power supply. I think it be suitable for this load, while external H-Bridge circuit might needed to be considered after output to alternate excitation current direction. 

    TPS92643 uses average current mode control which can achieve 4% accuracy current. For TPS92515, it senses peak current instead of average current, thus, load current is a little lower than regulated peak current and be affected by some factors like inductance, temperature. etc. (Please refer to Equ 5, 6 in TPS92515 datasheet 

  • +1 in reply to Xiaoguang
    Expert 1420 points

    Hi Xiaoguang,

    Yes, we are to use H bridge to alternate excitation current in coil.

    Anyways, thanks for your support. We shall either use TPS92515 or TPS92643.

    Regards,

    Jagdish