| Electronics > Beginners |
| Unexpected waveform class D output |
| (1/1) |
| lutkeveld:
I wanted to verify the output power of a Texas Instrument class D EVM (TAS5754MDCAEVM) After hooking up a 4 ohm test load and a 24V 5A power supply I got the following waveform after the LC output filter (see attachment) If I reduce the output to <1V the output is what I expected (two out of phase sines) However, when increasing the volume the individual outputs starts to distort, but the differential signal (purple) seems okay. Is this a problem? Do I measure incorrectly? My speakers dont seem to clip audibly. |
| Dat Tran:
Can you show me your circuit ? And which channel is output, input on your oscilloscope ? |
| lutkeveld:
The circuit is the TAS5754MDCAEVM, which is a 2x50W max class D amplifier. I am measuring one channel with a simple DSO. The output is differential, but the measurement is single ended. That is why I use the 'math function' on the scope to subtract the signals to get the differential output (purple). |
| T3sl4co1l:
Differential works, who cares? No idea why it's making unbalanced waveforms, you'd have to ask them (but I doubt they'll say why). Tim |
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