A question about Current Sense Amplifier and Overcurrent Comparator?

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A question about Current Sense Amplifier and Overcurrent Comparator?

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maxxu
Contributor III

Hi

    I have a question about Current Sense Amplifier and Overcurrent Comparator.

   I use the Hall current sensor to sample the current. I don't need the current operational amplifier on the chip to amplify the signal, but I need to use the over-current comparator. Therefore, I design the current operational amplifier as the emitter follower

    (i.e. AMPP [0] connects with the input signal, amp [0] connects with ampm [0])

    But the sampling data is not accurate. I would like to ask if this is not allowed.

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StanoA
NXP Employee
NXP Employee

Hello Maxxu,

Please read the AN5207: Hardware Design Guidelines for S12ZVM Microcontrollers and point to the Figure 29 and 30 with associated equations. You need the recalculate the feedback resistor and use the output voltage from the Hall sensor instead of the 200mV voltage from the current sense resistor.

The mentioned AN5207 - Hardware Design Guidelines for S12ZVM Microcontrollers is available on https://www.nxp.com/products/processors-and-microcontrollers/additional-mpu-mcus-architectures/s12-m...

I believe it will work properly for you.

 

 

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