INTRODUCTION OF OUR PRODUCT
The TPA2008D2 is a third generation 5-V class-D amplifier from Texas Instruments. Improvements to previous generation devices include:
DC volume control
Lower supply current
Lower noise floor
Higher efficiency
Smaller packaging
Fewer external components.
Most notably, a new filter-free class-D modulation technique allows the TPA2008D2 to directly drive the speakers, without needing a low-pass output filter consisting of two inductors and three capacitors per channel. Eliminating this output filter saves approximately 30% in system cost and 75% in PCB area.
FOR A TRADITIONAL CLASS D AMPLIFIER
The traditional class-D modulation scheme, which is used in the TPA032D0x family, has a differential output where each output is 180 degrees out of phase and changes from ground to the supply voltage, VCC. Therefore, the differential prefiltered output varies between positive and negative VCC, where filtered 50% duty cycle yields 0V across the load. The traditional class-D modulation scheme with voltage and current waveforms is shown in Figure 14. Note that even at an average of 0 V across the load (50% duty cycle), the current to the load is high, resulting in a high I2R loss, thus causing a high supply current.
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FOR OUR CLASS D AMPLIFIER
The TPA2008D2 uses a modulation scheme that still has each output switching from 0 to the supply voltage. However, OUTP and OUTN are now in phase with each other with no input. The duty cycle of OUTP is greater than 50% and OUTN is less than 50% for positive output voltages. The duty cycle of OUTP is less than 50% and OUTN is greater than 50% for negative output voltages. The voltage across the load sits at 0 V throughout most of the switching period, greatly reducing the switching current, which reduces any I2R losses in the load.
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Our produc is more performant because it doesn't create significant variations of current.
If it's necessary we can complement the systeme with a filter pass low:
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Download the Data sheets... (Document Adobe Acrobat)