I'm having a problem with load regulation errors on my board. When I engage our load with a relay, it causes a metering chip in our system to reset. I've placed a picture of the relay with the flyback circuitry below.
Some detail on the project:
The project details are sensitive, so we can only put so much online. But, let me know if you need any more specific details.
- We are controlling LED light ballasts.
- We are specifying
- the ballasts may draw up to 16A
- the ballast shall range from 85 - 277VAC, single-phase
- We are using a relay to disconnect the lamp from the AC line.
- The relay is in a normally closed configuration.
- We are taking the 90-267VAC down to 5V with a simple AC to DC converter and using that to power our system.
- We are metering the line using an IC meter.
For the sake of having reproducible results, we thought to use a large wattage rated resistor on an actively cooled heat sink to act as a constant load.
- The resistor is 500Ω rated for 150W
- We are running the system off of a BK Precision power supply that seems to drift by maybe 0.5VAC @ 120VAC (spec'd at 0.2% ±0.6VAC)
- The system draws about 0.249A of which about 25mA belongs to our circuit.
- When the relay is engaged, the load is disconnected, we see a ringing on the 5V line as well as on a regulated 3.3V line.
- When the relay is disengaged, we see the same ringing, but much more exaggerated. This is primarily when the metering chip resets.
- If we disconnect the load from neutral using a normally closed momentary switch, we see some 5V and 3.3V line voltage regulation errors. But, it very rarely causes a fault in our DC system as a whole.
So I was wondering if you can help me understand what I'm doing wrong in the circuit. I think it's related to the relay so that's the part of the schematic I included, if you need to see or know more, let me know.
Thank you very much.