AC/DC Converter used L6566B

[wei-hung]

Posted on October 24, 2013 at 03:35

Dear Sir,

I try to use eDesign Suite to inquiry the reference design and power controller IC, and it suggest to use L6566B for my application. I would like to use combination controller with PFC and PWM functions, and L6566B should be ok. But 1. there is no formula in datasheet or no item in eDsign Suite to estimate hold-up time in input capacitor(Cin). And I found in eDesign Suite if we change input capacitor with higher value, then will need to change not only switching MOSFET with higher breakdown voltage but also transformer with higher area product. What is the rule to achieve the optimal parameters? 2. Traditional approach will need PFC boost inductor and PWM transformer to achieve higher efficiency and lower ripple. Why does the scheme with L6566B not need PFC boost inductor? 3. And how about the THD property if using L6566B? Could you provide me a test data about THD for any L6566B EVM? Thanks David #hold-up-time #ac/dc #thd #l6566b

[ramator]

Posted on October 26, 2013 at 17:45

2. Traditional approach will need PFC boost inductor and PWM transformer to achieve higher efficiency and lower ripple. Why does the scheme with L6566B not need PFC boost inductor?

L6566B implements a voltage feed-forward function via a dedicated pin. Therefore, VCSX is modulated by the voltage on the VFF pin (#15) sensing the mains voltage through a resistor divider.