Inquiry for ISO5500 internal block

Atsushi Okui

Hello, all

Now I am considering to use ISO5500 for the replacement from HCPL-316J.

I am referring your datasheet to have investigation on this constructure.

I would like to know how this device avoid internal charging into capacitor, since generally the method to use capacitor could have charging then results in suppressing the internal transmission.

I assume that the RESET pin could ratch the internal capacitor to avoid the charging, which could suppress the internal transmission for input stage.

But, I would like to know how the output stage is processed to have internal communication smoothly.

Thank you in advance for your information.

Best regards,

over 12 years ago

0 Thomas Kugelstadt over 12 years ago

TI__Mastermind 28265 points

Please click on the Files section above or on the link below and download the document IIF-Digital Isolator Training. Here you find the principle operation of the isolator within the ISO5500.

regards, Thomas

0 Atsushi Okui over 12 years ago in reply to Thomas Kugelstadt

Genius 4015 points

Hello, thank you for your prompt reply.

Could you let me know once again the link for the download of IIF-Digital Isolator Training, since I could not find that on your comment?

Best regards,

0 Thomas Kugelstadt over 12 years ago in reply to Atsushi Okui

TI__Mastermind 28265 points

Okui-san,

I have attached an explanation of the ISO5500 internal isolation channel.

Regards, Thomas

ISO5500 Isolation Channel.pdf

0 Atsushi Okui over 12 years ago in reply to Thomas Kugelstadt

Genius 4015 points

Kugelstadt-san,

Thank you for your disclosing ISO5500 internal block.

As I referred the internal block, I would like to know the reason why VREF located between /A and /B, and A and B,

since on this case I assume that the charged capacitance on internal from VREF could not be discharged either.

Thank you once again for your clarification.

Best regards,

0 Oleksiy Pazyuk over 12 years ago in reply to Atsushi Okui

Expert 2585 points

Hi Okui,

As isolation capacitors create AC coupling between PWM and comparators to proper operation of the comparators DC bias should be provided to the comparator inputs.

Vref is only for biasing purpose thus this shouldn't create any issues with AC performances.

Reset pin exist only to reset DESAT fault condition which is indicated by low signal at /Fault pin.

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Inquiry for ISO5500 internal block