Hello!
I'm making a full bridge mains powered SMPS. It is operating at 170kHz, the mosfets are APT5015BVR, and the mosfet driver ICs are IR2113. The control circuits has a dedicates small 50Hz transformer. it's about 10-15VA.
When I first "launch" it up, I examined the small transformer, and the control circuits. Everything was OK, except the MOSFETs' GATE waveform wasn't as good as I expected.
After this, I feed the "power stage" from my variable voltage labPSU. And here came the problems...
I applied about 25V to the input of the SMPS, and the power consumption was about 0.6A. This means about 15W. There was NO LOAD at the output of the SMPS. I tried to remove the secondary side things (diode bridge), but no results.
Why was the idle power so high? Maybe the MOSFETs were cross-conducting? Or I made some mistake, while I was winding the transformer (ETD49), and I scratched the copper wire's insulation?
The previous prototype worked very good, I measured very good performance.
Here are some images of my 'scope:
The third image was taken from the current sense resistor. Thoose spikes show about 18-20A current-spike. 😱 😱
Here are the images in higher resolution:
http://sziget.mine.nu/~danko/aramkor/testbed/16/dscn9444.jpg
http://sziget.mine.nu/~danko/aramkor/testbed/16/dscn9446.jpg
http://sziget.mine.nu/~danko/aramkor/testbed/16/dscn9447.jpg
What can cause this?
I'm making a full bridge mains powered SMPS. It is operating at 170kHz, the mosfets are APT5015BVR, and the mosfet driver ICs are IR2113. The control circuits has a dedicates small 50Hz transformer. it's about 10-15VA.
When I first "launch" it up, I examined the small transformer, and the control circuits. Everything was OK, except the MOSFETs' GATE waveform wasn't as good as I expected.
After this, I feed the "power stage" from my variable voltage labPSU. And here came the problems...
I applied about 25V to the input of the SMPS, and the power consumption was about 0.6A. This means about 15W. There was NO LOAD at the output of the SMPS. I tried to remove the secondary side things (diode bridge), but no results.
Why was the idle power so high? Maybe the MOSFETs were cross-conducting? Or I made some mistake, while I was winding the transformer (ETD49), and I scratched the copper wire's insulation?
The previous prototype worked very good, I measured very good performance.
Here are some images of my 'scope:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The third image was taken from the current sense resistor. Thoose spikes show about 18-20A current-spike. 😱 😱
Here are the images in higher resolution:
http://sziget.mine.nu/~danko/aramkor/testbed/16/dscn9444.jpg
http://sziget.mine.nu/~danko/aramkor/testbed/16/dscn9446.jpg
http://sziget.mine.nu/~danko/aramkor/testbed/16/dscn9447.jpg
What can cause this?
Thanks Eva!
I'm going to increase the Dead-Time.
sss:
When I take thoose pictures, there were no snubber in the SMPS, but the place for them is on the PCB.
I'm going to increase the Dead-Time.
sss:
When I take thoose pictures, there were no snubber in the SMPS, but the place for them is on the PCB.
Watch out for current phase inconstancies which make maintaining correct dead times between bridge legs trickier.
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