L6563HTR STMicroelectronics, L6563HTR Datasheet - Page 29

• Manufacturer Part Number: L6563HTR
• Description: IC PFC CTRLR TRANSITION 16SOIC
• Manufacturer: STMicroelectronics

Specifications of L6563HTR

• Mode: Discontinuous (Transition)
• Current - Startup: 90µA
• Voltage - Supply: 10.3 V ~ 22.5 V
• Operating Temperature: -25°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• For Use With: 497-9082 - EVAL BOARD L6563 (200W)497-8850 - BOARD EVAL FOR L6563/STW55NM60N497-8834 - BOARD DEMO FOR L6563/LL6566A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-9075-2

L6563H
Figure 42. THD optimization: standard TM PFC controller (left side) and L6563H (right side)
6.5
Essentially, the circuit artificially increases the ON-time of the power switch with a positive
offset added to the output of the multiplier in the proximity of the line voltage zero-crossings.
This offset is reduced as the instantaneous line voltage increases, so that it becomes
negligible as the line voltage moves toward the top of the sinusoid. Furthermore the offset is
modulated by the voltage on the VFF pin (see “Voltage Feedforward” section) so as to have
little offset at low line, where energy transfer at zero crossings is typically quite good, and a
larger offset at high line where the energy transfer gets worse.
The effect of the circuit is shown in
PFC controller are compared to those of this chip.
To take maximum benefit from the THD optimizer circuit, the high-frequency filter capacitor
after the bridge rectifier should be minimized, compatibly with EMI filtering needs. A large
capacitance, in fact, introduces a conduction dead-angle of the AC input current in itself -
even with an ideal energy transfer by the PFC pre-regulator - thus reducing the effectiveness
of the optimizer circuit.
Tracking boost function
In some applications it may be advantageous to regulate the output voltage of the PFC pre-
regulator so that it tracks the RMS input voltage rather than at a fixed value like in
conventional boost pre-regulators. This is commonly referred to as “tracking boost” or
“follower boost” approach.
With the L6563H this can be realized by connecting a resistor (RT) between the TBO pin
and ground. The TBO pin presents a DC level equal to the peak of the MULT pin voltage and
is then representative of the mains RMS voltage. The resistor defines a current, equal to
Input current
Imains
Rectified mains voltage
Input current
MOSFET's drain voltage
Vdrain
Doc ID 16047 Rev 3
Figure 42
Input current
Imains
, where the key waveforms of a standard TM
Rectified mains voltage
MOSFET's drain voltage
Input current
Application information
Vdrain
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