I am using the BOB12009 llc to convert 3.3V signals to 5V. One of the signals is a data stream to neopixel strips. and that works as it should. The second signal is used to activate a solid state relay (SSR25 DA 3 to 32 volts input). The relay then turns on a power supply. I have checked that the 3.3 v signal is applied correctly, and that the high voltage side of the LLC changes from 0V to 2.7V, and therefore does not activate the relay. I thought the LLC module might be bad, so I replaced it with a new one, and I get the same voltages. I unhooked the wire from the output of the LLC, and found that the voltage now changes from 0V to 5V. Also, I connected the relay input directly to 5V and the relay worked OK. Could it be that the relay is drawing too much current? Perhaps Ill have to build a driver using a transistor circuit. Or could I use two LLC outputs to try to drive the relay?
Hi strickce.
The Bi-Directional Logic Level Converter is used for converting digital logic from one voltage to another at low current and can’t source enough current to switch a relay.
You might try the 3.3 volt signal you have now on it’s own to see if it can switch the relay by itself. If it’s not able to, a small NPN transistor like the 2N3904 should be able to drive a SSR with no trouble at all.