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Is there a recommended methode to an insulated control of the ACST435-8?

AHabe.1
Associate II
 
1 ACCEPTED SOLUTION

Accepted Solutions

It always depends on your load - inductive/resistive/capacitive/mixture/etc.

You can find some information in e.g. AN4993, additional information can usually be found in the application notes from the suppliers of the (zero crossing) optocoupler.

Regards

/Peter

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6 REPLIES 6
Peter BENSCH
ST Employee

Yes, by implementing galvanic isolation, e.g. using an optocoupler or zero crossing optocoupler, depending on your needs.

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Good luck!

/Peter

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AHabe.1
Associate II

Yes, of course we have to add an optocoupler or optotriac, but are there special requirements for the optocoupler or for the connection of optocoupler to the ACST435?

Is there an application note?

Thank you in advance.

Albert

It always depends on your load - inductive/resistive/capacitive/mixture/etc.

You can find some information in e.g. AN4993, additional information can usually be found in the application notes from the suppliers of the (zero crossing) optocoupler.

Regards

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.
AHabe.1
Associate II

Thank you Peter.

The AN4993 is very helpful.

AHabe.1
Associate II

Hi Peter,

now I have found the AN5114 on ST site.

This AN describes in a good manner the isolated controll of a TRIAC.

In chapter 3.3.1 there are the equations for determining the resistors.

But it seems that this equations do not really work for a ACST435 with 35mA gate current and for a photo-TRIAC with 1A surge current.

Could you please give me the recommended values for this TRIAC combination?

Thank you in advance

Albert

The values for the surrounding devices depend on several factors of the environment. That's why ST also provides TRIAC, SCR and ACS Simulator to simulate is using your parameters, like e.g. load type, conduction mode, controller topology and heat sink.

Regards

/Peter

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