TDA4817 Siemens Semiconductor, TDA4817 Datasheet - Page 11

• Manufacturer Part Number: TDA4817
• Description: Power Factor Controller IC for High Power Factor and Active Harmonic Filtering
• Manufacturer: Siemens Semiconductor

The TDA 4817 controls a boost converter as an active harmonic filter, drawing a sinusoidal line
current and providing a regulated DC voltage at the converter output.
The active harmonic filter improves the power factor in electronic ballasts for fluorescent lamps and
in switched-mode power supplies, reducing the harmonic content of the incoming, non rectified
mains current and if suitably dimensioned permitting operation at input voltages between 90 V and
270 V.
Benefits of TDA 4817 in Electronic Ballasts and SMPS
Semiconductor Group
Sinusoidal line current consumption
Power factor approaching 1 increases the power available from the AC line by more than 35 %
compared to conventional rectifier circuits. Circuit breakers and connectors become more
reliable because of the lower peak currents.
Active harmonic filtering reduces harmonic content in line current to meet VDE/IEC/EN-
standards.
Wide-range power supplies are easier to implement for AC input voltages of 90 to 250 V without
switch-over.
Preregulated DC output voltage provides optimal operating conditions for a subsequent
converter.
Reduced smoothing capacitance:
For a given amplitude of the 100/120 Hz ripple voltage the smoothing capacitance can be
reduced by 50 % in comparison to a conventional rectifier circuit.
Reduced choke size:
Rectifier circuits capable of more than 200 W usually employ chokes to decrease the charging
current ot the capacitor. These chokes are larger than those used in a preregulator with power-
factor control.
Higher efficiency:
A preregulator does cause some additional losses, but these are more than compensated for by
the cut in losses created by the rectifier configuration and the optimum operating conditions that
are produced for a subsequent converter, even in the event of supply-voltage fluctuations.
11
TDA 4817