Testing PFC/PWM Controller (CM6800) Out-of-Circuit

[OpenCircuit]

Are there any tests I can perform on this IC out-of-circuit that will allow me to draw any conclusions as to proper functionality?

My tool chest is rather limited: 12, 5 and 3.3v power supply, DMM (UT61E) and a DSO138 oscilloscope.

I have ordered replacement controllers, but this is just staring at me on my desk until they arrive. Testing MUST commence



I did supply 12v to Vcc and Gnd to Gnd expecting 7.5v on the reference signal that was not present.






I probed Ramp 1 and 2 with scope and got a flat signal. Every other terminal on the IC gave 60Hz
Thanks for any suggestions.

[danadak]

According to block diagram  the ref directly powered by Vcc and I see
no enable on the part. Double check your connections/dvm, you should
see the Vref. DVM should be on DC, scale for 10 V or so, leads plugged
into correct jacks. In fact check DVM by reading a 9V battery.


Regards, Dana.

[OpenCircuit]

Tried a few of the circuit simulators. It would be really nice if they had these ICs that we could drag /drop then mess around with.

I see PartSim has some PWM/PFC controllers in their database, but only pictorial

[lordvader88]

Yeah I just took a CM6800 PCB out of a Corsair CX600W, and also with just 10.5Vcc and gnd connected, I get NOTHING on any output, maybe a few millivolts, thats it. Total current is 490uA. Now I need to check it on the scope as I apply power. Its certainly not shorted out.

The 3M03X tri-MOSFET on that PCB is not shorted

According to this CM6800 Design Guide
http://www.bannerspan.com.tw/technical/Champion%20Micro/CM6800%20Design%20Guide.pdf

We should see Vref regardless.