Hey guys, I have a pedal (picture something like a sewing machine pedal) that has a micro switch inside of it to signal to the machine that its being pressed down. I then have a solid state relay (SSR) attached to the 2 wires (in parallel to the switch) so I can activate the pedal remotely. The 2 wires generally consist of a voltage source (not more than 15 volts), and a voltage sensor. The current draw is typically less than 20mA. This is the SSR I am using:
https://www.digikey.com/products/en?keywords=TLP3122A(TPLECT-ND
I'm driving the SSR directly with a STM32 GPIO and have a 180 ohm resistor in series with the SSR.
About 1 in 20 of these and the SSR fails in a closed/shorted mode. I can't understand why or how this is happening, or what I should do here? The voltage and current draw is far below the max values of the SSR. Some of them never fail, while others will fail within the first hour of use.
Any ideas what might be the problem, or how I should protect the circuit better? (or how to have it not fail in a closed/shorted mode, but have it open instead)? Thanks and any help/advice is greatly appreciated!
https://www.digikey.com/products/en?keywords=TLP3122A(TPLECT-ND
I'm driving the SSR directly with a STM32 GPIO and have a 180 ohm resistor in series with the SSR.
About 1 in 20 of these and the SSR fails in a closed/shorted mode. I can't understand why or how this is happening, or what I should do here? The voltage and current draw is far below the max values of the SSR. Some of them never fail, while others will fail within the first hour of use.
Any ideas what might be the problem, or how I should protect the circuit better? (or how to have it not fail in a closed/shorted mode, but have it open instead)? Thanks and any help/advice is greatly appreciated!
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