Philips Semiconductors
TDA1562Q application note
Koninklijke Philips Electronics N.V.
Application note Rev. 01.02 — 05 May 2006 44 of 62
At a signal frequency of 1kHz, the lift capacitors (8200 µF) can store sufficient energy to
sustain the sinewave even during heavy clipping (at Po=75W), which is shown in fig.32.
With smaller lift capacitors it might happen that the lift capacitors are drained
Fig 32. Current waveform during hard clipping
At an output level of 75W @ 1kHz the charge current for the lift capacitors reaches the
maximum value of 5A. As long as sufficient energy can be stored in the lift capacitors,
the amplifier will be able to sustain a continuous sine wave signal.
At low frequencies, the lift capacitors must deliver much more energy than at higher
frequencies, so at low frequencies the risk of “draining” the lift capacitors is much greater
than at high frequencies. Also, the charge circuitry is stressed much harder when low
frequency signals are amplified.
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