This seems pretty fast for a DPDT 8 amp 250 VAC relay.
I think this is public. Dropbox makes a positive effort to be confusing.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
We use a similar relay
It has 8ms turn in time, and we have tested for 1million operations. One of the guys wrote a program for an ESP32 so we can monitor it real time
Why are you using a TVS? To have it open faster? (we just use a tiny diode, current is maximum the same as relay peak current
Cheers
Klaus
The actual driver will be a TI TPIC6595, which has a flyback clamp voltage around 50 volts. The TVS is a pretty good model. TVS vs no TVS (mosfet avalanche?) doesn't seem to affect contact timing much. A clamp diode across the coil really does.
It makes a lot less audible noise with a diode across the coil.
My customer is asking if we can simulate a transient open circuit fault, and it looks like we can offer him a programmable open-circuit of maybe 10 milliseconds and up. We can do that in software, in a 1 ms IRQ kicking the SPI into the string of TI chips. We'd fudge the customer time request a bit, subtract 5 or 6 ms maybe.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
tirsdag den 25. februar 2020 kl. 20.49.26 UTC+1 skrev Klaus Kragelund:
"discharging" the coil with 48V-12V vs. the ~0.7V with a diode is faster
with right FET it can do the clamping, most drivers for things like fuel injectors are done like that to get fast closure
The TI driver has, essentially, a 45 volt zener drain to gate on each of its output fets. We'll just be careful to keep the relay driver traces away from any logic signals, although they are probably fairly slow.
My test board doesn't model the TI chip for slew rate.
I have just let the mosfet avalanche in other applications. Some are rated to do that safely. SiC can usually be allowed to avalanche too; GaN usually not.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
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