EVL90WADP-LLCSR STMicroelectronics, EVL90WADP-LLCSR Datasheet - Page 28

• Manufacturer Part Number: EVL90WADP-LLCSR
• Description: EVAL BOARD PORTABLE PWR SUPPLY
• Manufacturer: STMicroelectronics
• Type: Power Factor Correctionr

Specifications of EVL90WADP-LLCSR

• Main Purpose: AC/DC, Primary and Secondary Side with PFC
• Outputs And Type: 1, Isolated
• Power - Output: 90W
• Voltage - Output: 19V
• Current - Output: 4.75A
• Voltage - Input: 90 ~ 264VAC
• Regulator Topology: Boost
• Frequency - Switching: 130kHz
• Board Type: Fully Populated
• Utilized Ic / Part: L6563H, L6599A, SRK2000
• Input Voltage: 90 V to 264 V
• Output Voltage: 19 V
• Dimensions: 65 mm x 155 mm
• Product: Power Management Modules
• Supply Current: 4.75 A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: L6563H, L6599A, SRK2000
• Other names: 497-10377

Application information
6.4
Figure 41. THD optimizer circuit
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THD optimizer circuit
The L6563H 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 results in both minimizing the time interval where energy transfer is lacking and fully
discharging the high-frequency filter capacitor after the bridge.
Figure 41
shows the internal block diagram of the THD optimizer circuit.
Doc ID 16047 Rev 3
L6563H