14 thoughts on “Dcoi revisited part 2 – muppet 2 project”
Hi Julian. Really nice work. I intend to make my own DCOI using EL817 from Mouser. Can you describe the specs of your sharp opto-coupler or otherwise check the specs of mine to ascertain that it would work.
I really wouldn't recommend relying on the solder to hold the MOSFET to the 2-pin header; just stick the MOSFET pins directly into the machined-pin sockets. Or solder some short lengths of stranded hook-up wire between the MOSFET and the 2-pin header; let the wire flex, rather than the solder connection. 🙂
Interesting take on a MOSFET driver using PC817 optoisolators. IIRC most power transistor drivers that I see and work with in AC drives, inverters and power supplies use a HCPL3120 , TLP250 , or some varient of a high current optoisolator designed to drive high capacitive, high current gates of IGBTs and MOSFETs. Although in some applications I do see an IR2110 being used instead.
Why is the pwm frequency so high at 31khz?what's the advantage of a higher or lower pwm switching rate?I know DC motor controllers for EV's normally run about 20khz but I've never understood why so high
5v – (1.2 + 1.8) / 150 ~= 13mA driving the opto. Ic to the gate is only 10-20mA at best at 9V. A higher voltage or better CTR opto would improve the Mosfet turn on time. I tend to find a way to use the 4N32 darlington because I have a stick full of them as well 😉
Hi Julian. Really nice work. I intend to make my own DCOI using EL817 from Mouser. Can you describe the specs of your sharp opto-coupler or otherwise check the specs of mine to ascertain that it would work.
Hi julian, ive got a 29v (out put )battery i just made. Its not balanced, what voltage should i use to charge it.
Okay that is pretty cool.
This kind of educational videos are the reason I subscribed. I'm very happy to see them again 🙂
I really wouldn't recommend relying on the solder to hold the MOSFET to the 2-pin header; just stick the MOSFET pins directly into the machined-pin sockets. Or solder some short lengths of stranded hook-up wire between the MOSFET and the 2-pin header; let the wire flex, rather than the solder connection. 🙂
Aaargh… totally expecting to see the scope in action… now desperately waiting for part 3…
(Still a very interesting mini-series nonetheless. Thanks!)
which component tester is that you are using? Thanks
Interesting take on a MOSFET driver using PC817 optoisolators. IIRC most power transistor drivers that I see and work with in AC drives, inverters and power supplies use a HCPL3120 , TLP250 , or some varient of a high current optoisolator designed to drive high capacitive, high current gates of IGBTs and MOSFETs. Although in some applications I do see an IR2110 being used instead.
dcoi spends so much current through leds. how about using IRLZ44N ?
Why is the pwm frequency so high at 31khz?what's the advantage of a higher or lower pwm switching rate?I know DC motor controllers for EV's normally run about 20khz but I've never understood why so high
Where did you get that bluetac? I cant find it in the Shops here in Germany 🙁
Is this circuit also working with an input voltage of 3,3 volts?
5v – (1.2 + 1.8) / 150 ~= 13mA driving the opto. Ic to the gate is only 10-20mA at best at 9V. A higher voltage or better CTR opto would improve the Mosfet turn on time. I tend to find a way to use the 4N32 darlington because I have a stick full of them as well 😉
Do you use the antix tips from maplin or do you use a tip form a different make, shop etc?