EVL6564-100W STMicroelectronics, EVL6564-100W Datasheet - Page 22

• Manufacturer Part Number: EVL6564-100W
• Description: BOARD EVAL PFC FOR L6564D
• Manufacturer: STMicroelectronics
• Type: Power Factor Correctionr

Specifications of EVL6564-100W

• Main Purpose: AC/DC, Primary Side
• Outputs And Type: 1, Non-Isolated
• Power - Output: 100W
• Voltage - Output: 400V
• Voltage - Input: 90 ~ 265VAC
• Regulator Topology: Boost
• Frequency - Switching: 40kHz
• Board Type: Fully Populated
• Utilized Ic / Part: L6564
• Input Voltage: 90 V to 265 V
• Output Voltage: 400 V
• Dimensions: 90 mm x 83 mm
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption
• Current - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: L6564
• Other names: 497-10164

Application information
6.4
Figure 30. THD optimizer circuit
22/33
THD optimizer circuit
The L6564 is provided with a special circuit that reduces the conduction dead-angle
occurring to the AC input current near the zero-crossings of the line voltage (crossover
distortion). In this way the THD (total harmonic distortion) of the current is considerably
reduced.
A major cause of this distortion is the inability of the system to transfer energy effectively
when the instantaneous line voltage is very low. This effect is magnified by the high-
frequency filter capacitor placed after the bridge rectifier, which retains some residual
voltage that causes the diodes of the bridge rectifier to be reverse-biased and the input
current flow to temporarily stop.
To overcome this issue the device forces the PFC pre-regulator to process more energy
near the line voltage zero-crossings as compared to that commanded by the control loop.
This will result in both minimizing the time interval where energy transfer is lacking and fully
discharging the high-frequency filter capacitor after the bridge.
Figure 30
shows the internal block diagram of the THD optimizer circuit.
Doc ID 16202 Rev 2
L6564