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...

7

Winding limits the current into this pin. Additionally, by pulling this pin to ground, the drive pulses are disabled and the controller is placed in a low current standby mode. The NCP1606 features a powerful output driver on pin 7. This driver is capable of switching the gates of large MOSFETs in an efficient manner. The driver incorporates both active and passive pulldown circuitry to prevent the output from floating high when Vcc is off. Pin 8 (Vcc) powers the controller. When Vcc is below...