DER-865 output current at light off
Hi,
The new DER-865 looks like a great improvement compared to the earlier no-neutral designs. Great work and we look forward to implement this in our design. I just want to confirm; Is it correct that the 70mA is a Continuous output, also when the light is switched off (with a no-neutral design)?
Thanks in advance!
Comments
Hi, thank you for your response.
Apologies, I did not mean the standby current of the complete circuit. I was wondering if the buck converter also can provide the 70mA at all times to the BLE/Zigbee module? So also when the bulb/load is switched off? (in a 2-wire/no-neutral situation)
Thanks!
Hi,
It can provide 70 mA at all times when the switch is OFF in 2-wire configuration. On the other hand, this current will also flow to the bulb since it is connected in series with the dimmer. The load has to bleed this current in order to prevent light flickering in OFF state.
When the load is switched ON (2-wire mode), we did not verify with 70 mA load but I it will be tough to supply 70 mA at maximum conduction angle which is around 130 degrees. Increasing the bulk capacitor and output capacitor can help. Also, limiting the input voltage to high-line can increase the power supply capability since the rms voltage will be higher.
Thank you for your response and clarifications. Is it possible to request a sample PCB to do some tests with the circuit? I used the request form, but have not received a response.
Hi,
I have seen your request. I will follow-up with our Marketing group regarding your sample request.
Hi,
Thanks for your interest in this DER.
At light off, the standby current is < 200 uA. Please refer to figure 16 in the report.
For the 70 mA, this is the capability of the buck converter. However, the system itself consumes a lot less than 70 mA. In no-neutral application, especially dimming, it is important to minimize the consumption of the dimming circuit because it will limit the maximum conduction capability of the dimmer. This is why using a BLE module or Zigbee module are often used in no-neutral designs.
If you are designing with Line and Neutral, then the buck converter is already optimized for 70 mA.
Now, the actual load itself (light bulbs) are specified up to 250 W. The only limitation here is on thermal. Most dimmers use the metal plate to act as heatsink for the triac or mosfet. In the DER, we only used PCB mounting as heatsink.