Digging a little deeper, it seems that there will always be problems using aluminum as a conductor unless special care ($$$) is taken.
Found these related links when searching for "aluminum oxide contact resistance" which I thought were interesting...
Hello,
Looking for some help in understanding an issue that we are having which I think may be materials related.
We have an automotive module which is used to drive some relatively high current loads (5 - 20 A).
The module is roughly the size of a thick paperback book with a base made of A360...
Hi Mikekilroy,
Thank you very much for the information.
I double checked my notes and the motor inductance is actually ~ 100uH, so I'm actually only about 20x too low :)
I took the motor apart and found what I am pretty sure is a 470nF capacitor connected across the leads.
When I removed the...
I am not experienced with driving motors and would very much appreciate some guidance in a problem that I am having.
I am trying to drive a 12VDC, brushed motor, with a h-bridge driver / external MOSFETs combination.
I have no specs on the motor but I did measure ~ 1uH of inductance and 0.3...
Ian,
I have got a little further with how I think I want to proceed. I have selected the main components (I think) but still have to select some resistor values. I have installed LTspice and will try to simulate the circuit, but it may take a while as although I know how to "run" the...
LionelHutz - my first circuit does have this higher voltage clamp function, it was just my poor initial description of the circuit (in an attempt to limit discussion to the active clamp to BATT sub-circuit) that has caused confusion.
My symbol for Q1 shows a device with a PROT section connected...
murpia -
This is really not "basic" stuff" and I don't want you to hold my hand and lead me down the path of ignorance.
You have not read (or do not understand) what I am trying to accomplish. AGAIN! - I want to be able to turn on and off, a voltage clamp to BATT, with a minimal amount of...
LionelHutz -
The reason for having Q4 (and the overall reason for this posting) is that I have a couple of conflicting requirements for driving the injector during the "injection" event.
During the PWM, 1A current "hold" time, I want the current to recirculate through the injector for as long...
murpia,
Perhaps I was too quick to discount your suggestion.
Can you please detail your suggestion a bit more so that I can "see the light" (one less transistor is always better, unless it costs me $$$ to get rid of it).
I would appreciate it if you could identify an application note (or...
murpia and IRstuff,
I am looking to update a design that works fine with only a couple of transistors and a coupe of resistors, the only issue is that the Darlington will be have about 2V across it when it is on (only used in saturated mode). I am looking to update the design by using a...
Thank you dgallup for your reply, but I am aware of the LM1949. It is a very old part (not even available in surface mount) and really is intended for linear operation and not pwm. The transistor that it controls will act like a variable resistor and dissipate about 12W during the injector...
I am designing a peak-hold fuel injector driver and need some suggestions about modernizing a sub-circuit.
I need to have a means of "clamping" the injector to BATT during PWM of the "hold" current (a controlled "clamp"). I incorporated a "clamp" circuit that I found in an old injector driver...
