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Original question:

LM5056A: the reflow temperature curve of LM5056A

Current sensor for current-controlled FES circuit

john doe1
Prodigy 20 points
Part Number: LM5056A

Hi. Im looking for a current sensor that can measure +/-150mA and +/-100V with a resolution of about 5mA or less

The current sensor will be placed between a small transformer operating at 10kHz and a ~1kOhm load. If there isn't something that can handle the full range maybe there's a unidirectional sensor that can be protected against negative current or something. That would also work.

Here's a quick simulation I made so you can see the general layout of the circuit:

  • 0
    TI__Mastermind 29710 points

    Hello John Doe,

    I am sorry but we do not have a magic bullet for you.  If you need a device that measures both voltage and current we have limited device and they are digital.  This are limited to only the positive common mode.  From your circuit it looks like you are going to 144V.

    Another options is making a device that has have a power supply that moves along with your common mode voltage.  Then use a divider to measure the common mode voltage.

  • 0 in reply to Javier Contreras4
    Prodigy 20 points

    144V is peak to peak so +/-72V. I only need to measure current and I will use the current measurement to increase the voltage up to a maximum amount. I can control that with my microcontroller so I really only need the current feedback. Is there a way to limit the sensor to only read positive current/voltage?

  • 0 in reply to john doe1
    TI__Mastermind 29710 points

    I cannot think of a way.  Every way to limit the voltage will cause some error.  Like rectifying the voltage signal.  The easiest way to implement is with a current transformer.