Offline Controller, PFC and Half Bridge Resonant Mode, for LED Lighting

The NCL30051 is a combination of a power factor correction (PFC) and half-bridge resonant controller optimized for off-line LED lighting applications. The device integrates all the features needed to implement a hightly efficient and small form factor LED driver. It contains a critical conduction mode (CrM) fixed on time boost controller and a half-bridge resonant controller with a built-in 600 V high side gate driver. The half-bridge stage operates at a fixed frequency - greatly simplifying the control implementation. The output (current or voltage)regulation can be achieved by adjusting the PFC stage output voltage based on a feedback signal generated external to the controller. This device includes an enable input on the FFC feedback pin, PFC open feedback protection, and PFC overvoltage and undervoltage detectors. Other features included in the NCL30051 are a 600 V startup circuit and an adjustable frequency oscillator with a divide by 2 circuit to assure a balanced duty ratio. Controller sequencing is built-in simplying the system design.