23 September 2018
- Last edited 23 September 2018
Please remember, my Electronics skills are only enough to be dangerous, I am not skilled in the Art! However, I will try to answer the best to my ability.
The IRF3205 Datasheet, shows a Max Gate voltage of ±20 Volts:
This means you want to stay below ±20 Volts.
The Datasheet shows Gate Voltage Plot:
The Maximum Gate Voltage shown in this Plot is 12 Volts, well below the Maximum Rated ±20 Volts.
There are many solutions, and it depends on your requirements, but one solution would be to use a DC to DC Converter:
Isolated Board Mount DC/DC Converter, 2 Output, 2 W, 15 V, 66 mA, -15 V, 66 mA
On a lot of PCB's you will see circuitry like so:
It seems to be more so standard practice to implement DC Converters when a voltage change is required, this is why I chose this option first.
Or, as I have shown above, have your source Voltage at the required Voltage, say 15 Volts, and step down this supply to 5 volt or 3.3 volt using a Voltage Regulator:
The same can be done with a 3.3 Volt Regulator.
In my circuit:
I had a 12 Volt Source Supply, marked as VCC, and the following circuitry stepped down, and supplied, 5 Volts, (USB Cable) and 3.3 Volts, (small PCB Mount Voltage Regulator) to the Microcontroller using the following part:
USB-Serial SP Module:
Its worth noting, most Mosfet Circuits incorporate an 18 Volt Zener Diode for Gate protection, sometimes back to back:
Where D1 and D2 are Zener Diodes rated to 18 Volts. Meaning anything over 18 Volts is dumped to Ground. D1 might be a Ultra Fast Diode in some cases, and not a Zener Diode. The purpose of D1 is to stop the Mosfet turning on from reverse stray voltages. In this case one would not use R1, the pull down resistor and a proper Mosfet Driver to pull down the Mosfet.
So, it is common to use 12 to 15 volts as the Gate Voltage for Mosfets.
Please note, again, I am not skilled in the art, so others much more knowledgeable than me please correct me where I am not correct.
P.S: The VCC Pin on the Mosfet Driver, Pin 6 in the Datasheet marked as VDD, for the MCP1403 Driver, is the voltage supplied to the Mosfet Gate. No other Circuitry is required.
MCP1403 Mosfet Driver Circuit
For those skilled in the art, they already know my terminology is not correct:
VCC stands for "voltage at the common collector"
VDD stands for "Voltage Drain Drain"
Technically Vcc/Vee is for bipolar and Vdd/Vss for FETs, but in practise today Vcc and Vdd mean the same, and Vee and Vss mean the same.
And, Voltage Source Symbols should be marked as: