Which pin did you have the ch2 probe on for the high-side waveform?
Yes. It should be more square.
Yes. It should be more square.
What's the DC voltage (multimeter) measured directly across the capacitors CL1 and CL2?
If you look at the voltage across those capacitors with the scope (differential mode), do you get a straight line at about the same vertical deflection as you read with your meter?
If you look at the voltage across those capacitors with the scope (differential mode), do you get a straight line at about the same vertical deflection as you read with your meter?
Do you have another all N-channel class D amp that you could check the waveforms on (for the high-side) to see how they compare to this amp?
I'm not 100% sure that your scope is showing the correct high-side and simply want to confirm.
I'm not 100% sure that your scope is showing the correct high-side and simply want to confirm.
I´ve got another 8000D where i can measure the waves too, but the other one isn´t working either so far.
I measured the waveforms directly at the pins of the 21844.
I measured the waveforms directly at the pins of the 21844.
It doesn't need to be another 8000. Any all N-channel class D amp would be helpful. A 21844 amp would be a bonus.
I wouldn't ask you to buy one but if you do, a simple amp like the lightning audio - LA-1000MD (below) is a good amp to learn with. It's very simple but has a 21844 and a common PS driver board. Even if you break something when testing/learning, it's dead-simple and inexpensive to repair.
Attachments
How is this (the way it was taken) different from the original posts?
The originals were somewhat useless. That's why I wanted you to use differential mode.
The originals were somewhat useless. That's why I wanted you to use differential mode.
The high-side source is being driven rail-rail. Connecting the scope ground to the HS FET source will generally cause the amp to fail or will damage the scope's internal ground.
Does this scope have a ground pin on the mains power plug?
Does this scope have a ground pin on the mains power plug?