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Does MOSFET need current?
For bipolar transistors, a large base current is required to maintain low on-voltage. But because the input capacitance (Ciss) of the power MOSFET is rather large for high-speed switching, it is necessary to quickly charge the input capacitance with a low-impedance drive circuit. …
How fast is a MOSFET?
While it takes virtually no continuous current to turn the device on and off, it does take considerable pulse current to charge and discharge the gate quickly. Hundreds of milliamps or more are often needed for very fast switching. MOSFETs themselves can switch very quickly — often in 20 ns.
How to calculate the required gate current for power MOSFETs?
After my research I’ve come across two conflicting formula’s to calculate the amount of current needed to fully charge the gate capacitance of the power mosfets. Qgate = 115 nC from datasheet. Vgate = 12V from my circuit.
What is the dynamic characteristic of a MOSFET?
A dynamic characteristic which is the total charge of the MOSFET’s gate [nC]. It can be employed to estimate the instantaneous current needed to turn on a MOSFET in a specifed time. This is a design parameter to maximize or minimize the worst case input gate current [ns].
Can a MOSFET driver be used in a brushless DC motor?
In some small Brushless DC motor or stepper motor applications, the MOSFET driver can be used to directly drive the motor. For this application note, though, we are going to assume that a little more voltage and power capability is needed than what the MOSFET drivers can handle.
Which is the bridging element between the motor and MOSFET driver?
The bridging element between the motor and MOSFET driver is normally in the form of a power transistor. This can be a bipolar transistor, MOSFET or an Insulated Gate Bipolar Transistor (IGBT). In some small Brushless DC motor or stepper motor applications, the MOSFET driver can be used to directly drive the motor.