546

Changing the primary inductance value does not greatly affect the design parameters therefore a value of 800 H was used throughout. A higher inductance value would help lower the MOSFET peak current however a very large amount of inductance is needed to lower the ripple current by only a few mA. Additional cost spent on the magnetics is not worth the slightly improvement in current ripple. 2. Cout value is the amount of capacitance necessary to meet the 10 output voltage ripple requirement and...

Application Note

Power Factor Correction (PFC) is very much a necessity for off-line switchmode power supplies requiring output powers of 75 watts or more. Boost converters using discontinuous mode and critical conduction mode design approaches to PFC have been mostly relegated to the low power end of the power spectrum because of the low cost and simplicity of the circuitry. It turns out that the critical conduction mode approach offers the same simplicity and low cost for power factor correctors in the...

J2

2 Ttotal Vin min ) Vin min Another design criterion is the high current ripple in CRM. As a result of the high ripple, the core flux swing is bigger compared to the CCM mode. Higher flux swing results in higher core losses and rules out materials such as powdered iron. Detailed discussion on properties of the material is beyond the scope of this paper, but it is something to keep in mind in the design of the inductor. It is apparent from the above equations that the follower boost approach...