dandelion wrote on Jul 7th, 2008, 6:36pm:Visjnoe wrote on Jul 7th, 2008, 8:12am:Dear,
1. What do you mean by supply voltage pumping?
2. 2nH seems a good value for the bondwire inductance.
Would increasing it to 5nH let you replicate measurements?
3. Did you use an ideal voltage source for the supply in your simulations?
Or did you use some finite impedance?
Regards
Peter
Hi Oeter,
Thanks for the help.
1.About the supply voltage pump, pls. refer the link
http://www.diyaudio.com/forums/showthread/t-50861.html2.Yes, I tried the 5nH inductance, but it seemed no much effect
3.Yes, I uesd the ideal supply voltage in my simulations. Maybe U should add some finite impedance for my system verifications. I wonder how do you describe the supply voltage in system simulations?
Thanks a lot
To see if it is supply voltage pumping, try to add a small resistor(10ohm) between the VDD and the ground. The reverse current will be sunken by the small resistor.
Or you can add a huge capacitor between the VDD and the ground to minimize the rise in the VDD caused by the reverse current.
Monitor the signal after the LC filter and the pumped VDD. If the VDD is pumped up when the signal is negative, it should be due to the reverse current.
questions?
Are you using a single ended load not BTL?
Are you using the same regulator for the both of the digital VDD and the power stage?