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Unread 11-23-2005, 12:27 AM   #158
starbuck3733t
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Join Date: Nov 2002
Location: State College, PA
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The fact that I used R1 as a 1K resistor to simulate the load didn't help... should be more like 20 or 30 ohms. That and the fact that the VDC at the left of the schematic is me being lazy and simulating a TTL level input. Q1 acts as a switch to fully turn M2 off... 5V straight into Gate won't do it. With Q1 off, there are ~12V the Gate of M1 and it is turned on and therefor passes the V1 source through.

with Q1 turned on, M1 is turned off w\ 0V at it's gate and M2 is turned on with 0V at its gate and passes V2 into the load.

V1 simply represents a given voltage input, not a 7V source. V2 is the same. In reality when this is incorporated into the rest of the chassis control system, V1 will be full 12V and V2 will be the input from the mobo's PWM (speedfan rox!).

(the encrypted bit is the SPICE netlist run through rot13 )
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