i have constructed the circuit below to control a halogen bulb with two MOSFETS.
previously i had been having issues trying to derive a dc supply voltage for my gate drive opto.
Though the circuit above seems to work and the uneven power dissipation seen prior appears to have been solved.
Onto the capacitor question: when i vary my duty cycle i can see the voltage of my cap (C1) drop from 12V to around 8.5V. This isnt much of an issue for the fets that i'm using as Rds(ON) reaches a minimum around 8V.
Though i was wondering what steps i could take to keep the capacitor voltage higher?
The cap i have in place is a 330uf bog standard electrolytic, though i do have a few 35V 220uf low ESR caps i can butcher from fried buck converters.
I guess i could use caps with a higher rating?
Also, i am wondering if there is any recommended MOSFET heat-sink types? (my fets are TO-247AC)
The Fets get above 100 Celsius at the moment.
This is breadboarded currently but i will be using Vero-board when i am confident with the circuit.
Any guidance is appreciated, as always.
Thanks!
previously i had been having issues trying to derive a dc supply voltage for my gate drive opto.
Though the circuit above seems to work and the uneven power dissipation seen prior appears to have been solved.
Onto the capacitor question: when i vary my duty cycle i can see the voltage of my cap (C1) drop from 12V to around 8.5V. This isnt much of an issue for the fets that i'm using as Rds(ON) reaches a minimum around 8V.
Though i was wondering what steps i could take to keep the capacitor voltage higher?
The cap i have in place is a 330uf bog standard electrolytic, though i do have a few 35V 220uf low ESR caps i can butcher from fried buck converters.
I guess i could use caps with a higher rating?
Also, i am wondering if there is any recommended MOSFET heat-sink types? (my fets are TO-247AC)
The Fets get above 100 Celsius at the moment.
This is breadboarded currently but i will be using Vero-board when i am confident with the circuit.
Any guidance is appreciated, as always.
Thanks!
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