TMS320F280049C: Optocoupler and TL431 rejection of line frequency ripple

Cherry,

How did the customer design the control loop of LLC? do you have the frequency response plot?

If you are specifically asking TL431, it's better to create a separate thread.

Best,

John

Hi John,

Thanks for your support.

The customer made a 300 kHz power supply using optocoupler and TL431 in closed loop, and the ripple was always below the requirement.

Why are TI's related closed-loop reference designs using optocoupler+TL431 all 100 kHz? Is optocoupler and TL431 not suitable for high frequency digital power?

Thanks and regards,

Cherry

Hi Cherry,

Did the customer design their own solution based on TI reference design? if so, can you specify the reference design number?

Best,

John

Hi John,

No, the customer  just wonder if LLC can use optocoupler +TL431 for closed loop at high frequencies such as 300 kHz or 1 MHz. And will optocouplers not respond as quickly as possible? 

Thanks and regards,

Cherry

Cherry,

Please create another thread for TL431 and ask for support from TL431 experts.

Best,

John