Hey,
I am having some problem with some bad rining on my power supply which is causing all kind of problems. I would like to understand why this occurs and figure out how to stop it. Any help resolving this would be appreciated!
I am trying to drive a linear actuator but am finding some strange ringing when I initially retract the actuator which dissapears quickly. The problem is this ringing appears all over my system! When using an alternative rotational motor I do not see any ringing, the problem is I am stuck with this linear actuator!
I have made an H-Bridge using the HIP4081. I am using the demo board provided by Intersil described in the data sheet with IRF520 FETs and have put two 680uF caps across the supply as suggested. I am driving the HIP4081 with an 8 bit AVR, feeding two 5V phase correct PWM signals into ALI and BLI and pulling BHI and AHI high.
I can see the rininging on the battery, 4 gates, and two PWM drives. The ringing seems to be full scale and have a frequency of 10 or 20 MHz.
I've uploaded two pics of captures of the two low side gate drives and two high side gate drives. These are not at the same time period (I only have two channels!)
[img=http://img407.imageshack.us/img407/5559/ablow160lin.th.jpg]
[img=http://img13.imageshack.us/img13/2852/abhigh160.th.jpg]
I am using the phase correct PWM method described here (http://web.mit.edu/orca/www/2004_motorController.shtml) and should be avoiding any shoot through.
If anyone has any thoughts I'd appreciate it.
Colin
I am having some problem with some bad rining on my power supply which is causing all kind of problems. I would like to understand why this occurs and figure out how to stop it. Any help resolving this would be appreciated!
I am trying to drive a linear actuator but am finding some strange ringing when I initially retract the actuator which dissapears quickly. The problem is this ringing appears all over my system! When using an alternative rotational motor I do not see any ringing, the problem is I am stuck with this linear actuator!
I have made an H-Bridge using the HIP4081. I am using the demo board provided by Intersil described in the data sheet with IRF520 FETs and have put two 680uF caps across the supply as suggested. I am driving the HIP4081 with an 8 bit AVR, feeding two 5V phase correct PWM signals into ALI and BLI and pulling BHI and AHI high.
I can see the rininging on the battery, 4 gates, and two PWM drives. The ringing seems to be full scale and have a frequency of 10 or 20 MHz.
I've uploaded two pics of captures of the two low side gate drives and two high side gate drives. These are not at the same time period (I only have two channels!)
[img=http://img407.imageshack.us/img407/5559/ablow160lin.th.jpg]
[img=http://img13.imageshack.us/img13/2852/abhigh160.th.jpg]
I am using the phase correct PWM method described here (http://web.mit.edu/orca/www/2004_motorController.shtml) and should be avoiding any shoot through.
If anyone has any thoughts I'd appreciate it.
Colin