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PFC Inductor Series Power Factor Correction (This spec sheet is also available in printable format) Features: Available for use in power ratings from 200W to 1000W. Operate with controllers from several IC manufacturers. Range from 1000µH to 100µH under full load, and are designed for 100kHz operation. Designed using the industry standard input voltage range 85VAC - 385VAC at 50/60Hz. Use a toroidal geometry to allow the use of thicker wire to decrease DCresistance and yield higher current capacity. Use industry standard vertical through-hole mounting configurations and have an operating temperature range of –20°C to +105°C.

				Key Considerations for PFC Inductors PL Product Calculator

Precision works with its customers to optimize a PFC solution for any specific application. In many cases, audible noise is not a problem. For example, when the power supply is housed in an enclosure with forced air, the PFC Inductor noise is not detectable and allows a lower cost solution. Also, if size is not the highest priority, there are many available options. Precision can provide additional windings on the PFC Inductor to supply power for the PFC control circuitry. Using a voltage doubler circuit with this bias winding provides a semi-regulated output that is quite stable over the entire duty cycle range. Power factor is the ratio of the real power to apparent power. Power factor can vary between 0 and 1, and can be either inductive (lagging, pointing up) or capacitive (leading, pointing down). In order to reduce a capacitive (or leading) power factor, an inductor is added to make the power factor equal 1. The whole purpose of making the power factor equal to one is to make the circuit look purely resistive (apparent power equal to real power).

Precision Part Number	Output Power (Watts)	Inductance @ 0A (µH)	Inductance @ Ipeak (µH)	Ipeak (Amps)	Iripple, p-p (Amps)	Irms (Amps)
PFC-01101-01	200	1980	830	4.2	1.1	2.6
PFC-01102-00	300	810	460	6.2	1.6	3.9
PFC-02301-00	400	570	375	8.3	2.2	5.1
PFC-04301-00	500	460	310	10.4	2.7	6.4
PFC-04302-00	600	430	250	12.5	3.2	7.7
PFC-05301-00	700	300	220	14.5	3.8	9.0
PFC-05302-00	800	260	185	16.6	4.3	10.3
PFC-05303-00	1000	220	148	20.8	5.4	12.8

Precision Model  Number Figure Number MAX A MAX B MAX C ± 0.005 D ± .005 E + 0.015 / 0.005 F PFC-01101-01 1 in 1.67  0.8 1.77 0.05 0.6 0.9 mm 42.5 20.3 45 1.3 15.2 22.9 PFC-01102-00 1 in 1.67 0.8 1.77 0.05 0.6 0.9 mm 42.5 20.3 45 1.3 15.2 22.9 PFC-02301-00 1 in 2 0.9 2.1 0.05 0.7 1.2 mm 50.8 22.9 53.3 1.3 17.8 30.5 PFC-04301-00 2 in 2.88 1.39 2.31 0.04 1.05 1.6 mm 57.9 35.31 58.7 1.02 26.7 40.64 PFC-04302-00 2 in 2.28 1.3 2.31 0.045 1.05 1.6 mm 57.9 33 58.7 1.14 26.7 40.64 PFC-05301-00 2 in 2.75 1.39 2.82 0.057 1.1 1.7 mm 69.9 35.3 71.6 1.45 27.9 43.2 PFC-05302-00 2 in 2.75 1.39 2.82 0.064 1.1 1.7 mm 69.9 35.3 71.6 1.63 27.9 43.2 PFC-05303-00 2 in 2.80 1.39 2.83 .072 1.1 1.7 mm 71.1 35.3 71.9 1.83 27.9 43.2 Notes: * Specification is subject to change without notice

Power Factor Correction (PFC) Magnetics Checklist
(This design checklist t is also available in printable format.)

In recent years, power factor correction (PFC) has been gaining momentum. While the U.S. does not have any existing regulatory requirements, in Europe, the employment of PFC in power supplies is necessary to meet the European EN61000-3-2 regulatory standard. As the U.S. government continues to emphasize energy conservation and efficiency, the domestic need for PFC is on horizon. While many design considerations exist for a PFC circuit, the design of PFC magnetics hinge upon a few key parameters. Precision Inc. has created a checklist to demystify these parameters and ensure that key design considerations are addressed.

	Power level in Watts • Output of the PFC • Do not fail to include the efficiency of the downstream DC/DC converter when determining the required PFC output power.	Lacking better information, assume 85% efficiency for the DC/DC.
	Input voltage range • Usually 85-265VAC	85-265V input range includes worst-case for a label rating of 100-240V
	Input frequency range • Usually 50-60 Hz	Some applications require 400 Hz. This doesn't usually affect the magnetics appreciably but it does have some implicationsfor the control method.
	Operating frequency • Fixed or variable	Fixed frequency operation is only available in Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) operation.Boundary Conduction Mode (BCM)) is variable frequency.
	Output voltage • Fixed, usually 390VDC or tracking	Tracking output voltage may offer some advantage at low mains voltages, but it requires a wider input range on the DC/DC. If this method is chosen, verify that the efficiency of the DC/DC does not degrade at low input.
	Conducted EMI requirements • Class A or Class B	EMI requirements will mostly affect the design of the input filter. Normally, at least one common-mode inductor will be required.
	Topology • Single-switch boost • Two-phase interleaved boost	Two-switch interleaved topology may result in smaller individual components, but there will be more of them and statistical reliability should be considered. Also the choice of controllers is not as great.
	Operating mode • Continuous inductor current • Boundary-mode • Discontinuous inductor current	Discontinuous and boundary mode control both produce high ripple current in the inductor (2x the average current) which increases the inductor loss and also the conducted EMI. But at low power levels (usually under 100W), these items are manageable and the control method is simple and robust. The inductor usually requires a sense winding for zero-current detection. At high power levels, CCM is the only realistic choice.
	Average vs. maximum output power	Many PFCs are used in applications where the maximum rated power output is not continuously required. This may allow some relaxation of the thermal requirements on the inductor.
	Auxiliary output requirements • Voltage • Number of aux windings • Isolation	CCM PFCs can very effectively use an auxiliary winding of a few turns to generate a surprisingly stable DC voltage for operating the controller after startup. Also, it is relatively easy to make the aux winding comply with SELV requirements so a secondary-side control voltage can be provided.
	Stray field from the PFC inductor	In some crowded applications, the stray field from the inductor may cause a problem. Toroids are not always the best solution in this regard, and some ferrite shapes can be considered (potcore, RM core).
	Physical size constraints and mounting considerations	Size can be partly driven by (9) above. Also, when calculating the inductance, it is important to understand that it is OK for the value to swing downward as much as 50% at maximum current. This is why materials other than ferrite are usually chosen. Ferrite saturates abruptly where powdered iron, Kool Mu, MPP and related materials do not.
	Temperature rise constraints • Usually the magnetics are not the issue	The inductor in a well-designed PFC is not usually a major loss item. Also, allowing a fair amount of swing may allow a smaller core which will have less core loss.
	Cost objective	Cost is driven mostly by choice of core material andmounting hardware

The checklist above presents a list of parameters generally applicable to most PFC applications. Contact Precision Inc. for custom requirements specific to the desired application.