ADUM 4221 and miximum duty cycle and power supply of the high side

Hi Michael,

Thanks for using the ADuM4221 in your design.

In the schematic, I can only see the Bootstrap circuit and not the DC/DC that you mentioned.

May I know how you implemented the DC/DC regulator that supplies the secondary side of the ADuM4221? Is the DC/DC regulator for high side and low side isolated with each other? Where is the power from the DC/DC coming from - Primary side or Secondary Side?

Thanks and regards,

Jefferson

Hello Jeco,

Thank you for your help !

We actually using with the bootstrap but we want to test the ADUM4221 without bootstrap to go to 100% of our PWM, so we just make a prototype and remove R4/D2 and R5/D3 and add one DC/DC converter for each high side of the driver to power up each side individually (as you can see on the picture)

but when we start our new prototype the driving failed after 1/2 seconds and burn the driver

Hi Michael,

correct me if I'm wrong, you tied the low side supplies to a single +12V supply and you add 2 more 12V supplies to supply each of the 2 High-Side drivers.

Does the High-side and Low-side 12V supplies for each Leg were isolated with each other? Your 3 supplies need to be isolated with each other.

Where are the 12V supply powered from? Did you try checking the GND connections of your 3 12V supplies to see if they are all isolated with each other?

Thanks and regarrds,

Jefferson

Hi Michael,

correct me if I'm wrong, you tied the low side supplies to a single +12V supply and you add 2 more 12V supplies to supply each of the 2 High-Side drivers.

Does the High-side and Low-side 12V supplies for each Leg were isolated with each other? Your 3 supplies need to be isolated with each other.

Where are the 12V supply powered from? Did you try checking the GND connections of your 3 12V supplies to see if they are all isolated with each other?

Thanks and regarrds,

Jefferson