NCP1623ASNT1G

The NCP1623 is a controller designed to drive PFC boost stages. Based on an innovative Valley Synchronized Frequency Fold-back (VSFF) method, it operates in critical conduction mode (CrM) until the power drops below a threshold level. The PFC controller enters discontinuous conduction mode (DCM) with increased dead-time as the load further decays (frequency foldback). VSFF maximizes the efficiency at both nominal and light loads. In addition, an internal circuitry ensures a near-unity power factor even when the switching frequency is reduced.

Housed in a TSOP-6 package, the circuit also incorporates the features necessary for robust and compact PFC stages, with few external components. The A version provides the follower boost capability for drastic low-line efficiency improvement. This controller is also available in the SOIC-8 package, which features an ultra-low-consumption mode externally controlled by the disable pin.

Key Features

• Critical Conduction Mode (CrM) in heavy load conditions
• Discontinuous Conduction Mode (DCM) with Frequency Foldback in light load
• Follower Boost capability (NCP1623A only)
• Sleep Mode with circuit consumption below 100 µA (SOIC-8 version only)
• Zero Current Detection via Drain sensing
• Dynamic Response Enhancer
• Near unity power factor over the load range

Application

• Power Factor Correction
• Offline Power Supply