I've searched and have seen so many different ways and opinions on how to do this, I'm wondering which one is the simplest and best method (for a low side switch). Trigger is from computer and is 5V logic.
This is for use in an automobile ignition system to turn the ignition coil on/off. Typically the MOSFET will be on for a few mS and the maximum duty cycle at high RPM would have the MOSFET on for no more than 30-40% of the time, much less at lower RPM. The coil will draw a max of about 7A, and the computer is programmed to allow the coil just enough time to saturate before turning off. So the MOSFET will not have to carry 7A the entire time it's on, as it takes about 1-1.5 mS for the current to build to this level.
Some people say use a logic level MOSFET, others say use a transistor to provide the necessary gate drive and others say use a driver IC. I've looked at driver IC's as they seem like a foolproof method, but ones I've found seem to have pairs of drivers (H & L) which seems like a waste.
Any help much appreciated.
This is for use in an automobile ignition system to turn the ignition coil on/off. Typically the MOSFET will be on for a few mS and the maximum duty cycle at high RPM would have the MOSFET on for no more than 30-40% of the time, much less at lower RPM. The coil will draw a max of about 7A, and the computer is programmed to allow the coil just enough time to saturate before turning off. So the MOSFET will not have to carry 7A the entire time it's on, as it takes about 1-1.5 mS for the current to build to this level.
Some people say use a logic level MOSFET, others say use a transistor to provide the necessary gate drive and others say use a driver IC. I've looked at driver IC's as they seem like a foolproof method, but ones I've found seem to have pairs of drivers (H & L) which seems like a waste.
Any help much appreciated.
