TIDA-01494: PFC_LLC

Priyanka Kumari

Prodigy 80 points

Part Number: TIDA-01494

How to calculate the output voltage of PFC section?

How is the input of LLC section related with PFC output section?

The given design have given LLC input voltage range of 300-397-410. Please elaborate it how it comes?

over 2 years ago

0 Priyanka Kumari over 2 years ago

Prodigy 80 points

We have 85-190V derating & 190-265V full rating

0 Benjamin Lough over 2 years ago in reply to Priyanka Kumari

TI__Mastermind 26495 points

Hi Priyanka,

1. The output voltage of the PFC section is set by 5V * (R33+R19+R18+R24)/R33. For this particular design, the PFC output voltage is set to 395V.

2. The input range of the LLC is 300V up to 410V with ~395V typical. The LLC power stage is optimized for typical input voltage. The motivation for allowing down to 300V input is to give some holdup time from when AC input is removed to when the output voltage shuts down. Up to 410V is to allow some margin for load transient and low frequency bus ripple that may increase the bus voltage (it is for design margin).

Best Regards,

Ben Lough

0 Priyanka Kumari over 2 years ago in reply to Benjamin Lough

Prodigy 80 points

Ans 2 is not clear to me. can you please simplify it. Actually i want an idea of how the voltage, current, power flow correlate if we are using PFC+LLC in our design.

0 Benjamin Lough over 2 years ago in reply to Priyanka Kumari

TI__Mastermind 26495 points

Hi Priyanka,

The output voltage of the PFC is the input of the LLC. The PFC takes the AC input, converts it to a 395Vdc bus and sends it to the LLC. The LLC converts the 395Vdc bus to an isolated 24Vdc.

Best Regards,

Ben Lough

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TIDA-01494: PFC_LLC