Hi
I have several projects underway but all have common factors - logic level supply and high(ish) level outputs.
The logic is from Basic Stamps at the moment and the outputs need to drive Nitinol wires (muscle wire), stepper motors or cree high power LEDs. Operating frequencies are unlikely to exceed 200Hz.
I was hoping to make 'universal' boxes (one per coil for the steppers) to fit between these devices so that I can just re-use them in the future.
As I work in a school, the main sources of low volts tend to be chunky transformer units with full wave rectification and nothing much else. If needed I could scavenge the PSU out of a PC to give a cleaner source of power.
The circuit that I think would suit all of these is pretty much the one shown in figure 10 at the bottom of page 5 of http://www.vishay.com/docs/81227/81227.pdf but using a diode-protected power MOSFET instead of the IGBT.(I got some IRF540 Power Mosfet 28A 100V at 25p each which I hope to use). The only addition that I would make to the circuit is a current-limiting resistor for the muscle wire and the LED projects in series with the load and perhaps a resistor and/or zener diode to protect the input LED from over-voltage.
There seem to be several optocoupler gate driver chips and I can't see much difference between them at the frequencies that I am using. Fairchild FOD3180 (2A output), FOD3181 (0.5A output) as well as some made by NEC and others.
Somehow, this circuit seems too simple! Have I missed something?
I would greatly appreciate any insight you can give me on this, and I appreciate your time spent.
I have several projects underway but all have common factors - logic level supply and high(ish) level outputs.
The logic is from Basic Stamps at the moment and the outputs need to drive Nitinol wires (muscle wire), stepper motors or cree high power LEDs. Operating frequencies are unlikely to exceed 200Hz.
I was hoping to make 'universal' boxes (one per coil for the steppers) to fit between these devices so that I can just re-use them in the future.
As I work in a school, the main sources of low volts tend to be chunky transformer units with full wave rectification and nothing much else. If needed I could scavenge the PSU out of a PC to give a cleaner source of power.
The circuit that I think would suit all of these is pretty much the one shown in figure 10 at the bottom of page 5 of http://www.vishay.com/docs/81227/81227.pdf but using a diode-protected power MOSFET instead of the IGBT.(I got some IRF540 Power Mosfet 28A 100V at 25p each which I hope to use). The only addition that I would make to the circuit is a current-limiting resistor for the muscle wire and the LED projects in series with the load and perhaps a resistor and/or zener diode to protect the input LED from over-voltage.
There seem to be several optocoupler gate driver chips and I can't see much difference between them at the frequencies that I am using. Fairchild FOD3180 (2A output), FOD3181 (0.5A output) as well as some made by NEC and others.
Somehow, this circuit seems too simple! Have I missed something?
I would greatly appreciate any insight you can give me on this, and I appreciate your time spent.