I need to turn ON/OFF an 12V 10A SMPS supply by a relay. I want to switch the SMPS via its line input using a microcontroller. I need a normally open non-latching magnetic relay such that the SMPS should be ON only if the microcontroller digital output is ON. The SMPS sources 6A on the DC side but sinks less than 1A RMS from the grid. I found this 110 mW relay which can be controlled 5VDC. Here is the relay datasheet.
From the datasheet what I understand is that when 5VDC is applied to its coil terminals, it passes 22 mA and its DC resistance is 227 Ω.
I'm planning to use the following single transistor interface to control the relay coil:
I have made a DC sweep in SPICE. Here are the plots:
With the above values the 2N2222 goes into full saturation at around 1.8V. In my case I will use a 3.3V microcontroller digital output. I also used a 1N4148 diode as a fast flyback diode to prevent high voltage spikes at the collector node.
The 2N2222A can handle collector current up to 800mA. In this case, the current is around 22 mA.
So far I couldn't find a problem myself in the above circuit interface for that particular relay.
Are there be any fundamental problems with this in terms of the components and their values, such as EMI causing false switching etc? I thought there may be some more details I might need to look into about the relay and transistor specifications.