So I designed a circuit to drive mosfets through which high powered devices will be connected to.

These devices are mainly a led bar of (24 V, 3 A), a high powered relays (24 V, 30 A) and a dc motor (12 V, 30 A) in my lab.

The low side gate driver I choose is the UCC27517DBVT and it will be controlled by a microcontroller such as the arduino. The LED bar will be driven with pwm and the relay as a switch.

One of my concerns was the choice of mosfet I made, knowing that the one selected only dissipates 26 W and that the vgs optimal for a low RDS On is 10V and full current of ID = 40 A.


Basically I'd like to get feedback to know if these circuits need to be modified or if they are over engineered for the purpose of device control and flexibility.

Thanks !

 

Mainly good, but the 1k resistors spoil it. No point in using a 4A driver, then limiting its current to 10mA!
The gate drive resistors should be in the region of 10Ω.
However, if you are not using PWM to dim the LEDs or speed-control the motor, it is questionable if a low-side driver is required at all with a logic-level MOSFET. It is a good idea in that it protects the microcontroller from any nasty voltage around the MOSFET and probably will protect the microcontroller if the MOSFET fails.
Be careful that you don't exceed the maximum gate voltage (which must be elsewhere on the datasheet)

 

And why do you think you need a TVS on the gate of your MOSFET?

 

Your Relay specifications are vague, does it have ~30-Amp-Contacts,
or does the Armature-Coil draw ~30-Amps ?

Does Your LED-Array have built-in Current-Regulation, or are they raw LEDs ?.
Do the LEDs need to be dimmable ?

Is the Relay supposed to control Power to the LEDs ?, or does it have some other function ?

Assuming that the Relay draws around 1/2-Amp,
and that it is supposed to control the LEDs,
I would completely skip the Relay altogether,
but if the Relay serves some other unknown function, I suppose it could somehow be useful,
but there are probably more elegant Solid-State solutions.

With the vague descriptions it's hard to say whether these setups are good or poor-choices.

My first guess would be that a better solution to both Circuits
would be to simply use a ~30-Amp FET-Gate-Driver to simplify things greatly, and add to Circuit versatility,
( the suggested Gate-Driver would be the only active Component, and can handle ~8-Amps continuous ).
( It also will Source and Sink 8-Amps, whereas the usual FET can only Sink-Current, and contains a Diode ).
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