Power factor control scheme (NCP1654) - power circuit - circuit diagram - Huaqiang Electronic Network

The NCP1654 is a controller for Continuous Conduction Mode (CCM) power factor corrected step-up pre-converters. It controls the power switch conduction time (PWM) in a fixed frequency mode and is dependent on the instantaneous coil current.

The circuit uses an SO8 package structure that minimizes the number of external components and greatly simplifies PFC devices. It also features high security protection, making the NCP1654 a driver for rugged, compact PFC controllers, like an efficient input supply runaway clamp circuit.

Main features of NCP1654

• Meet the requirements of IEC61000-3-2

• Average current continuous conduction mode

• Fast transient response

• Very few external components

• Very low startup current (<75μA)

• Very low shutdown current (<400μA)

• Low operating power consumption

• 1.5A push-pull output circuit gate drive

• Accurate fully integrated 65/133/200kHz oscillator

• Closed loop PWM for cycle-by-cycle duty cycle control

• Internally balanced internal reflection

• Hysteresis undervoltage lockout

• Soft start for smooth start-up

• Shutdown function

• Pin to pin meets industry standard requirements

• Lead-free components


Figure 1 NCP1654 functional block diagram