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Correct Schematics added for reference.
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Prashant
Prashant
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I am working on a DC load circuit and have put together a simple configuration based on templates available online. As you can see in 3rd image attached, I am noticing a small ringing in the load circuit measured at R1 which is a current sense resistor. I am assuming its being generated from the OPAMP not being able to stablise quick enough and so I tried different random solutions like adding 10 pF capacitor between MOSFET base and ground however I am unable to completely get rid of the ringing.

Can anyone suggest a methodological approach to stablise the opamp and remove this ringing?

Thanks,

  1. Schematics Schematics

  2. Full output Vsingal vs I(R2)

Full graph

  1. Ringing zoomed Ringing

Edit 1 in response: Final schematics with added RC filter on 2nd stage opamp to Spehro'sfilter out ringing. Adding to original post in case anyone's looking for similar solution: Schematic with capacitor c1

Final Schematics

I am working on a DC load circuit and have put together a simple configuration based on templates available online. As you can see in 3rd image attached, I am noticing a small ringing in the load circuit measured at R1 which is a current sense resistor. I am assuming its being generated from the OPAMP not being able to stablise quick enough and so I tried different random solutions like adding 10 pF capacitor between MOSFET base and ground however I am unable to completely get rid of the ringing.

Can anyone suggest a methodological approach to stablise the opamp and remove this ringing?

Thanks,

  1. Schematics Schematics

  2. Full output Vsingal vs I(R2)

Full graph

  1. Ringing zoomed Ringing

Edit 1 in response to Spehro's solution: Schematic with capacitor c1

I am working on a DC load circuit and have put together a simple configuration based on templates available online. As you can see in 3rd image attached, I am noticing a small ringing in the load circuit measured at R1 which is a current sense resistor. I am assuming its being generated from the OPAMP not being able to stablise quick enough and so I tried different random solutions like adding 10 pF capacitor between MOSFET base and ground however I am unable to completely get rid of the ringing.

Can anyone suggest a methodological approach to stablise the opamp and remove this ringing?

Thanks,

  1. Schematics Schematics

  2. Full output Vsingal vs I(R2)

Full graph

  1. Ringing zoomed Ringing

Edit: Final schematics with added RC filter on 2nd stage opamp to filter out ringing. Adding to original post in case anyone's looking for similar solution:

Final Schematics

added 130 characters in body
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Prashant
Prashant
  • 131
  • 7

I am working on a DC load circuit and have put together a simple configuration based on templates available online. As you can see in 3rd image attached, I am noticing a small ringing in the load circuit measured at R1 which is a current sense resistor. I am assuming its being generated from the OPAMP not being able to stablise quick enough and so I tried different random solutions like adding 10 pF capacitor between MOSFET base and ground however I am unable to completely get rid of the ringing.

Can anyone suggest a methodological approach to stablise the opamp and remove this ringing?

Thanks,

  1. Schematics Schematics

  2. Full output Vsingal vs I(R2)

Full graph

  1. Ringing zoomed Ringing

Edit 1 in response to Spehro's solution: Schematic with capacitor c1

I am working on a DC load circuit and have put together a simple configuration based on templates available online. As you can see in 3rd image attached, I am noticing a small ringing in the load circuit measured at R1 which is a current sense resistor. I am assuming its being generated from the OPAMP not being able to stablise quick enough and so I tried different random solutions like adding 10 pF capacitor between MOSFET base and ground however I am unable to completely get rid of the ringing.

Can anyone suggest a methodological approach to stablise the opamp and remove this ringing?

Thanks,

  1. Schematics Schematics

  2. Full output Vsingal vs I(R2)

Full graph

  1. Ringing zoomed Ringing

I am working on a DC load circuit and have put together a simple configuration based on templates available online. As you can see in 3rd image attached, I am noticing a small ringing in the load circuit measured at R1 which is a current sense resistor. I am assuming its being generated from the OPAMP not being able to stablise quick enough and so I tried different random solutions like adding 10 pF capacitor between MOSFET base and ground however I am unable to completely get rid of the ringing.

Can anyone suggest a methodological approach to stablise the opamp and remove this ringing?

Thanks,

  1. Schematics Schematics

  2. Full output Vsingal vs I(R2)

Full graph

  1. Ringing zoomed Ringing

Edit 1 in response to Spehro's solution: Schematic with capacitor c1

edited body; edited title
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winny
winny
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Ringing issue in DC Loadload circuit simulation in LTSpice

I am working on a DC Loadload circuit and have put together a simple configuration based on templates available online. As you can see in 3rd image attached, I am noticing a small ringing in the Load Circuitload circuit measured at R1 which is a current sense resistor. I am assuming its being generated from the OPAMP not being able to stablise quick enough and so I tried different random solutions like adding 10pF10 pF capacitor between MOSFEtMOSFET base and ground however I am unable to completely get rid of the ringing.

Can anyone suggest a methodological approach to stablise the opamp and remove this ringing  ?

Thanks,

  1. Schematics Schematics

  2. Full output Vsingal vs I(R2)

Full graph

  1. Ringing zoomed Ringing

Ringing issue in DC Load circuit simulation in LTSpice

I am working on a DC Load circuit and have put together a simple configuration based on templates available online. As you can see in 3rd image attached, I am noticing a small ringing in the Load Circuit measured at R1 which is a current sense resistor. I am assuming its being generated from the OPAMP not being able to stablise quick enough and so I tried different random solutions like adding 10pF capacitor between MOSFEt base and ground however I am unable to completely get rid of the ringing.

Can anyone suggest a methodological approach to stablise the opamp and remove this ringing  ?

Thanks,

  1. Schematics Schematics

  2. Full output Vsingal vs I(R2)

Full graph

  1. Ringing zoomed Ringing

Ringing issue in DC load circuit simulation in LTSpice

I am working on a DC load circuit and have put together a simple configuration based on templates available online. As you can see in 3rd image attached, I am noticing a small ringing in the load circuit measured at R1 which is a current sense resistor. I am assuming its being generated from the OPAMP not being able to stablise quick enough and so I tried different random solutions like adding 10 pF capacitor between MOSFET base and ground however I am unable to completely get rid of the ringing.

Can anyone suggest a methodological approach to stablise the opamp and remove this ringing?

Thanks,

  1. Schematics Schematics

  2. Full output Vsingal vs I(R2)

Full graph

  1. Ringing zoomed Ringing
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Prashant
Prashant
  • 131
  • 7