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INA199: INA199

Debanjan chatterjee
Intellectual 325 points
Part Number: INA199
Other Parts Discussed in Thread: AMC1301

Hello,

I am trying to sense current flowing through a GAN device for peak current mode control and also for over current protection.  The gan will conduct peak current of over 20A and will block above 200V when off. I intend to introduce a sense resistor in the gate to source power path of the GAN. I intend to use a current sense amplifier to amplify the signal across a 2mOhm sense resistor and use it for my purpose in comparator , Is INA199 the ideal amplifier for the application?

If the use the amplifier in the source path of will the common mode voltage exceed the value specified since the gan blocks 200V?  What should be the common mode voltage of  an amplifier connected in low voltage side of power mosfets if the mosfet blocks " xV" voltage when off.

Regards

  • 0
    TI__Mastermind 32395 points
    Hello Debanjan,

    The the common-mode voltage of the inputs for a current shunt monitor (CSM or CSA) should never exceed the Absolute Maximum range. If you place the CSM on the low-side (in between ground and the MOSFET), then you should not have to worry about a 200V common mode at the input pins, but you will need a device that withstand a 0V common-mode (e.g., INA199). If you place on the high-side, then you need a device that can withstand a 200V common-mode (AMC1301).

    If you place your CSM and shunt resistor in-line, then the device must be able to withstand common-mode voltages of 0V and 200V (if that is the DC voltage input to your GAN).

    Unfortunately, we do not have regular CSM's with 200V common-mode capabilities. We do have special isolated CSMs that can withstand very high voltage (e.g, AMC1301). Additionally, we have have TI design called "48V 3-Phase Inverter with Shunt-based In-line Motor Phase Current Sensing Reference Design" which discusses the theory in measuring current with GaN drivers.

    Sincerely,
    Peter Iliya
    Current Sensing Amplifier Applications