Hey Lewis. I know your channel is very small but the information you publish has been very valuable. My professor used your some of your TTL logic level shifting circuits in my undergrad engineering degree. We even use some of your circuits at work for our industry (Building Automation). Keep up the good work.
@LewisLoflin I really appreciate all the videos you have done and have seen most of them. I started looking at power electronics because I wanted to build a remote controlled lawnmower using 24v 250-350w wheelchair motors. I could not believe the price of the sabretooth 2x60 and for this reason have spent probably too much time learning about these. What I would really like you to confirm please, is that for simple pwm dc motor control, the use of even a half-bridge is actually a real waste of time, money and in fact is inefficient especially important if you want to run things off batteries. All you need is mosfets on one side of the motor only. Indeed you just waste increased amounts of heat through the second set of mosfets in the half-bridge. Relays would be a more efficient way of reversing at the ouput stage of a quarter h bridge to the motor, to change the polarity of the motor connections. H bridges are wasteful unless you need 3 of them for brushless dc motor control, or where there are low current requirements. One interesting thing watching youtube videos is that even with mosfets of a relatively low rds that are driven fully, how much heat they need and the requirement for cooling. I cannot see that smd components do anything but cut that by half from 1mOhm to 0.5mOhm (still valuable). One thing which shocked me was how hot the even "1/4" h bridge controllers get.
I watched the other video that is associated with this, in which you have an LM317 for current limiting on a separate PCB. Any chance you've looked to convert the pair of circuits to limit current via feedback to the switcher, rather than limiting in a linear fashion?
That is a drawback of SPS. I used larger caps than the spec. sheet called for. I had no problem. As for audio amps, I'm not sure, to be honest. I'm building a 2nd generation version of this and will use an oscilloscope to check for noise.
Hey Lewis. I know your channel is very small but the information you publish has been very valuable. My professor used your some of your TTL logic level shifting circuits in my undergrad engineering degree. We even use some of your circuits at work for our industry (Building Automation). Keep up the good work.
I always admire your videos. Cant expect such technical error Sir.
@LewisLoflin I really appreciate all the videos you have done and have seen most of them.
I started looking at power electronics because I wanted to build a remote controlled lawnmower using 24v 250-350w wheelchair motors. I could not believe the price of the sabretooth 2x60 and for this reason have spent probably too much time learning about these.
What I would really like you to confirm please, is that for simple pwm dc motor control, the use of even a half-bridge is actually a real waste of time, money and in fact is inefficient especially important if you want to run things off batteries. All you need is mosfets on one side of the motor only. Indeed you just waste increased amounts of heat through the second set of mosfets in the half-bridge.
Relays would be a more efficient way of reversing at the ouput stage of a quarter h bridge to the motor, to change the polarity of the motor connections.
H bridges are wasteful unless you need 3 of them for brushless dc motor control, or where there are low current requirements. One interesting thing watching youtube videos is that even with mosfets of a relatively low rds that are driven fully, how much heat they need and the requirement for cooling. I cannot see that smd components do anything but cut that by half from 1mOhm to 0.5mOhm (still valuable).
One thing which shocked me was how hot the even "1/4" h bridge controllers get.
This is better the 2nd time around. 😎 Thank you.
I watched the other video that is associated with this, in which you have an LM317 for current limiting on a separate PCB. Any chance you've looked to convert the pair of circuits to limit current via feedback to the switcher, rather than limiting in a linear fashion?
Excellent - ERROR FORGIVEN
Very interesting content
Glad you think so!
Thanks for the video, how about noise? if I use this switching circuit on a radio or amplifier, will I hear noise from the switching supply? thanks!
That is a drawback of SPS. I used larger caps than the spec. sheet called for. I had no problem. As for audio amps, I'm not sure, to be honest. I'm building a 2nd generation version of this and will use an oscilloscope to check for noise.