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Circuit Operation Description
5-1-3(C) PFC (Power Factor Correction) Circuit Descriptions
The current electric devices use DC power supply and require a rectifier circuit converting AC into DC.
As most rectifier circuits apply a capacitor input type, the rectifier circuit becomes the core of the occur-
rence of harmonics with lower reverse rate.If various electronic and electric devices are connected to a
power system, high-frequency current will occur due to a power rectifier circuit, a phase control circuit
with power input current of non-sine wave, or components with non-linear load characteristics, such as
capacitor, inductor, etc. As the result, the disturbance of voltage occurs, and finally a power capacitor or
a transformer generates heat, fire or noise occurs, controls malfunction, or the accessed devices abnor-
mally operate or their lives are shortened.To prevent those symptoms, IEC (International
Electrotechnical Commission) regulated standards for Power Supply Harmonics.
(Refer to IEC 1000-3-2.)Figure 8 shows the basic structure of Active Boost PFC and waveforms.
Scale: Devices accessed to 220V/380V, 230V/400V, 240V/425V and lower than 16A (IEC 100-3-2)
Devices with AC 230V and lower than 16A (IEC 555-2)
Applied Classes :
p Class A : Devices not included in another class
p Class B : Portable tools
p Class C : Lighting devices
p Class D : Devices with special current waveforms
Application Schedule : Except the devices less than rating input of 75W (1996~1999)
5-6
Standards for Power Supply Harmonics
Except the devices less than rating input of 50W (2000 and after)
Samsung Electronics
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