• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 47 subscribers
  • Views 249 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

AMC23C10: Clarification on Grounding and Neutral Connection for AMC23C10 in ZCD Application.

DEEPAK KUMAR
Prodigy 20 points

Part Number: AMC23C10

Hello Team,

I am planning to use the AMC23C10 isolated comparator for a zero-cross detection (ZCD) circuit with an AC mains input.

In the datasheet application circuit, it appears that the input return (GND1) on the primary side is connected in a way that could be interpreted as being tied to the AC neutral. Since I am using a low-voltage supply (around 5V) on the primary side, this raises a concern:

If the primary-side ground (GND1) is connected to AC neutral, does that effectively short the low-voltage ground to the mains neutral? Is this configuration safe and recommended?

I would like clarification on the correct way to connect:

  • AC mains (Line/Neutral)

  • Primary-side supply (VDD1, GND1)

  • Isolation boundaries between primary and secondary sides

Specifically:

  1. Should GND1 be directly connected to AC neutral, or should it remain floating?

  2. What is the recommended safe grounding scheme when using AMC23C10 for ZCD in mains applications?

Any guidance or reference design would be very helpful.

Thanks in advance.

Subject: Clarification on Grounding and Neutral Connection for AMC23C10 in ZCD Application

Hello Team,

I am planning to use the AMC23C10 isolated comparator for a zero-cross detection (ZCD) circuit with an AC mains input.

In the datasheet application circuit, it appears that the input return (GND1) on the primary side is connected in a way that could be interpreted as being tied to the AC neutral. Since I am using a low-voltage supply (around 5V) on the primary side, this raises a concern:

If the primary-side ground (GND1) is connected to AC neutral, does that effectively short the low-voltage ground to the mains neutral? Is this configuration safe and recommended?

I would like clarification on the correct way to connect:

  • AC mains (Line/Neutral)

  • Primary-side supply (VDD1, GND1)

  • Isolation boundaries between primary and secondary sides

Specifically:

  1. Should GND1 be directly connected to AC neutral, or should it remain floating?

  2. What is the recommended safe grounding scheme when using AMC23C10 for ZCD in mains applications?

Any guidance or reference design would be very helpful.image.png

Thanks in advance.

  • 0
    TI__Expert 7560 points

    Hi Deepak,

    DEEPAK KUMAR said:

    In the datasheet application circuit, it appears that the input return (GND1) on the primary side is connected in a way that could be interpreted as being tied to the AC neutral. Since I am using a low-voltage supply (around 5V) on the primary side, this raises a concern:

    If the primary-side ground (GND1) is connected to AC neutral, does that effectively short the low-voltage ground to the mains neutral? Is this configuration safe and recommended?

    The GND1 pin would be connected directly to Neutral or Line depending on your system and configuration.  The high-side supply of the device (VDD1 to GND1) would need to also be isolated from the low-side.  This supply could be derived from the mains on the high side or through a transformer or isolated supply from the low-side (You can take a look at this document for examples: https://www.ti.com/lit/an/sdaa154/sdaa154.pdf?).

    Also, please look at this app note on zero cross detection: Isolated Zero-Cross Detection Circuit

    Thanks.

  • 0 in reply to Saleh Ahmad
    Prodigy 20 points

    I have attached the draft schematic. Could you please verify if this is the correct approach to use?