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Old 09-26-2013, 01:41 AM   #157 (permalink)
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Hi Adam,

Originally Posted by adamj12b View Post

As for the pads for the terminals, I just place 3 holes intersecting. It has not been a problem yet.
I just read that some pcb houses do not like it because it breaks their drill bits. But maybe it is a bigger problem with smaller size drills.

Diodes are MUR1100E.
I see D1, connecting to VCE of the VLA500 is a MUR1100E, but what about the others, D2-D7 in the gate drive part of the circuit? On the pcb they look smaller and on your schematic they do not have values.

Talking of the drive circuit, I see in the Semikron document, on page 44 they mention using resistors on the emitter side of the circuit too. Ever experimented with that? The document I read was:
www . evbmw . com / igbt.pdf

The precharge circuit is as follows.

Pin 3 of the 23 pin connector is a connection to the B+ before contactors. This is feed through a 100R high power resistor, switched by Q8, an N channel MOSFET and then connects to the cap + terminal. The contactor output is justa 12V signal common to the 12V in the vehicle. The 15V dc-dc output shares a ground with the negative side of the capacitor. I dont think I realized this before. It was something I think I thought about thought about but did not correct because the Uprising driver has a second dc-dc and isolated the controls from the battery. I might need to look back into this. I dont want to add another dc-dc converter so the fet that switch's the precharge resistor. I didnt want to use the battery feed to power the fet as this would restrict what voltages could be used with the logic board. I want to be able to precharge anything between 12 and 400VDC.
That is how I read it, but wanted to make sure that I miss not miss something. One can probably use a small relay, like many other designs, the solid state would be nice though.

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