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?
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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?
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
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.
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