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Thank you for the reply.
I am not familiar with the terms "2-level" or "3-level" PWM. When I tried searching, all I seemed to get were references to inverter topologies (generating sinewaves).
Can you please point me to a reference as to how these terms relate to driving a DC motor with an...
I started working on an already partially designed h-bridge driver for a DC brushed motor.
Long story - short, the bulk capacitors are getting very hot.
As I have never designed an h-bridge circuit before (and I don't think the original engineer did either), I started by trying to find some...
eem2am,
This "problem" is not making any sense at all, so I will not continue beyond this message.
If your system cannot detect the water temperature fast enough to prevent scalding, then your system is deficient.
If the mixing valve is in an environment that is "well below zero C" then the...
eem2am,
Assuming that your thermistor is in the "mixed" pipe, I have a hard time believing that it would be 0C from the ambient temperature without any water flow (who takes a shower in a 0C environment). So let's say that the thermistor is reading 23C, once you attempt to "dribble" the cold...
eem2am,
You have described having a problem that just doesn't make any practical sense.
Is your product specified to work with 0C water?
Was this a single customer, that had an issue one time, because magically he knew that he had 0C water available but that the valve would not operate?
How...
Hi,
Not sure I understand. You are breaking valves because you are applying to much force to them when they are frozen.
Is there not a clear driver current difference when operating the motor normally and when the valve is frozen?
I think that this has gotten way more complicated than it needs to be (too many chefs?). Just place a suitable value resistor between the uC and the MOSFET (470?). Where do you see a problem with doing just this? And why are you PWMing this solenoid at such a high frequency?
eem2am -
I have read through this thread and the many suggestions offered, but I am still a bit confused.
I see that you are concerned about the gate drive not going to 0V from .4V quickly, but as others have already pointed out, the MOSFET is turned off at this point anyway.
What exactly...
Hi Genomerics,
For some reason I was not notified of your latest replies. I appreciate all the assistance that you have provided.
I will load your circuit into LTspice and "play" with it and let you know what I come up with.
Thank you
Genome -
I think I am ready to ask you some questions (please forgive my ignorance).
1. Why turn on the M2 mosfet with a current limited source (why can't I get rid of Q2 and connect the Q1 emitter to gnd?)?
2. Under what scenario is the zener protecting the gate of M2?
Thank you
p.s. I...
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...
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