M2500.1d output help.

[rhempz01]

The board I'm working on is a standered China class d. I fixed the power supply and driver board new 640 in the power supply. And it still draws current. And I think something is off. I took 2 pictures of the output mosfets. One side is at a way lower voltage than the other. One side is at -4.6v the other -61.5v.

 

[rhempz01]

Other side.

 

[rhempz01]

I can't seem to figure out what's wrong with it. All gate drives are good. Could use some help. It starts to draw current when it gets up past 9.3v that's the voltage I been working on it with. Ideas?

 

[Perry Babin]

Do any of the FETs get hot when you go above 9.3v?

 

[rhempz01]

I'll check perry I tested the power supply without the regulators, none got hot good clean drive signal. All the irf640's are new from mouser.? Maybe a driver to the outputs. Or a soder bridge. But I went thru everything again. Nothing out.. I'll check the fets again at 12.3 it runs a 4amps....

 

[Perry Babin]

Regulators or rectifiers?

 

[MarioRestucci]

The board I'm working on is a standered China class d. I fixed the power supply and driver board new 640 in the power supply.

irf640 is not powersupply fets but amp stage fets.
In the power supply, the correct fet is irf3205

 

[rhempz01]

Nothing getting hot amp is running fine .88amps at 12v. The outputs do not have any voltage higher than mv?

 

[rhempz01]

These the drivers for the outputs?

 

[rhempz01]

Rectifier perry sorry.

 

[Perry Babin]

With all of the rectifiers out and the rail caps discharged, post a photo of the low side drive with the same settings as you used for the high-side FETs.

 

[rhempz01]

Low side is the middle leg on the 640n perry? This I have a nice sqaure on the legs of the boards but I can't get that at the outputs.

 

[rhempz01]

I think I see how it works. Each side high and low.

 

[Perry Babin]

The high and low side waveforms should be very similar. The last image you posted is nothing but noise.

 

[rhempz01]

And they should be square correct? I don't have any clear signal on any of the legs of the outputs. Only a sqaure on the driver board on three of the legs. I should have a square for the high and low side correct. I do not.

 

[Perry Babin]

The following images are low and high-side drive (look at the file names of the images) with NO rectifiers.

Both images have the source leg grounded.

 

[rhempz01]

I removed the rectifiers to solve the drive problem. I don't think the ic failed. It has a board with 2 74hc02d for drivers. That the signal I get from the board legs, but not at the output fets. It must be the transistors? 2l, 2x I don't have any of those, is there another transistor I can use? L6, m6? Anyway I check again tommorow. I been using auto function on the scope to find the drive signal. The pictures help I had that before something failed as soon as I installed new psfets.?

 

[Perry Babin]

Do you have a good signal on the input and output of the opto-coupler?

 

[rhempz01]

Should I have a good sqaure wave at the octa coupler perry? I learned as much as I could about the high side and low side last night. I'm a bit more knowlegable. Do you know what these chips are in the center? I have the driver I/c's. Is it some sort of op amp? I just got off work I'm going to check that signal now.

 

[rhempz01]

Should I have a good sqaure wave at the octa coupler perry? I learned as much as I could about the high side and low side last night. I'm a bit more knowlegable. Do you know what these chips are in the center? I have the driver I/c's. Is it some sort of op amp? I just got off work I'm going to check that signal now.