PFC controllers cover a wide range

Two new power factor correction controllers are designed for use in power supplies with input levels all the way from 75W to several kilowatts.

Continuing to provide power supply manufacturers with innovative ways to reduce both standby and active power consumption, ON Semiconductor has released two new power factor correction (PFC) controllers designed for use in power supplies with input levels from 75W to several kilowatts.

The new NCP1653 and NCP1601 controllers are ideal for power factor correction in power supplies found in televisions, flat-screen monitors, PC desktop and notebook adapter SMPS, offline battery chargers and white goods such as refrigerators, washers and dryers.

The NCP1653 is a fixed-frequency, current-mode PFC controller designed to efficiently drive continuous conduction mode (CCM) boost convertors with mid-to-high power needs (100W to 3kW).

In addition to the usual fixed-output voltage operation, it can also operate with the output voltage tracking the input voltage, called follower boost.

In spite of its simplicity (8-pin package), it includes many of the features found in more complex controllers: Average current-mode or voltage-mode control, soft-start, input undervoltage lockout with hysteresis, undervoltage, overvoltage and overpower protection and thermal shutdown with hysteresis.

The NCP1601 is a controller designed for PFC boost circuits in the lower power ranges (up to 300W).

It operates in either fixed-frequency discontinuous conduction mode (DCM) and/or variable frequency critical conduction mode (CRM) and takes advantage of the best features of both modes.

In DCM it can be synchronised to an external frequency source or set at a fixed frequency.

As the load and line conditions cause it to approach the continuous conduction mode, the output drive is delayed to cause it to operate in CRM (operating frequency now becomes variable).

In both cases, the usual challenges of the recovery (soft turnoff) of the PFC diode are avoided, component stresses are reduced, along with the attendant costs.

Filtering requirements are simplified and light load efficiency is improved as a result of limiting the maximum frequency.

Both the NCP1653 and the NCP1601 are offered in compact PDIP-8 and SO-8 packages.

The NCP1653 is priced at $0.66 per unit in 10,000 unit quantities.

The NCP1601 is priced at $ 0.36 per unit in 10,000 unit quantities.

With the introduction of the NCP1601 and NCP1653, ON Semiconductor now offers the widest range of PFC solutions to meet the rapidly-emerging efficiency goals and the input harmonic limits of IEC1000-3-2.

These solutions cover a full power range from 50W to several kilowatts and cater to various PFC topologies.

Distinguishing the company's devices are innovative features such as follower boost option that allows reduction in PFC stage losses and component sizes, robust protection features including input power limiting and availability of complete design-in tools including easy-to-use design aids downloadable from the company's website.

The design software for these devices makes it possible to turn out a working circuit design, including stress analysis of key components, in a matter of minutes.

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