Looking for a Single Channel IC with Schmitt trigger and ESD Protection on its pin

Thread Starter

mohtishamali

Joined Jul 9, 2021
6
Greeting of the day to all,
I am working on thyristor gate driver and to make my design robust against any sort of parasitic interference's i want to introduce schmitt trigger as well as ESD protection on my control signal which will trigger my gate driver. i have 24 V DC coming from outside world and i have to protect it from ESD protection and also have to apply schmitt trigger. I did this with opamps with clamping diodes but unfortunately the propagation delay is not acceptable for my application. Can anyone here can please recommend a single channel driver IC having schmitt trigger and ESD protection on its pin for 24 V DC signal. I found many myself but they are from 3.3 to 5 V signal. Thanks in advance
 

Ian0

Joined Aug 7, 2020
3,766
Does the logic signal share a common ground with the thyristor cathode?
What voltages are your upper and lower input thresholds?
How much drive current does the thyristor gate require?
 

Thread Starter

mohtishamali

Joined Jul 9, 2021
6
NO Logic signal shares DC ground of 24 V DC supply while cathode has AC ground which is for voltage applied between anode to cathode that is 325 Peak to Peak. for 5 V of control signal i need 3.5 V for upper and 2.2 V for lower threshold. thyristor will trigger at 100mA.
 

Ian0

Joined Aug 7, 2020
3,766
If your logic ground is isolated from the thyristor cathode, then you need an opto-thyristor to trigger the thyistor, such as TLP748, or an opto-triac such as MOC3021 with a diode in series.
If you use a 555 to drive the opto-coupler, you will get thresholds of 3.33V and 1.67V. If 2.2V is s rigid requirement, then the upper and lower levels can be modified with resistors.
Don't use a MOC3041 zero-cross opto-triac as the zero-crossing detector doesn't work properly if there is a series diode.

Also worth bearing in mind that half-wave control of mains will fail EMC regulations in most countries, unless it's a hair-dryer.
 
Top