Procedure for ground referenced and high side gate drive circuits ac coupled and transformer isolated solutions are described in great details.
Gate drive transformer circuit.
They also are used for voltage isolation and impedance matching.
In some applications digital isolators or opto couplers may provide the means to drive mosfet s directly but gate drive transformers are preferred for higher voltage requirements and have the advantage of much lower turn on and turn off delay times as well as the capability to.
These devices provide electrical pulses for turning on and off semiconductors such as high voltage power mosfets or igbts.
This transformer is a bi directional link between the ground referenced control ic and the floating gate drive.
A gate drive transformer functioning in this manner could also be called a pulse transformer.
A gate drive transformer isolates the controlling gate drive circuit from the switch node when driving the mosfet gate and may also scale the output voltage via an appropriate primary to secondary turns ratio.
Gate driver circuits need an isolated floating bias supply to maintain the required turn on bias when the fet source rises to the input voltage.
Zeners are frequently used to protect the gate from transients.
A gate drive transformer isolates the controlling gate drive circuit from the switch node when driving the mosfet gate and may also scale the output voltage via an appropriate primary to secondary turns ratio.
They also are used for voltage isolation and impedance matching.
Gate drive transformers are essentially pulse transformers that are used.
The gate drive described in this paper uses a printed circuit board based transformer in combination with the memory effect of the power mosfet input capacitance to achieve the isolation.
Most circuit designers would consider these gate drive transformers to be a type of pulse transformer.
This is explained in more detail in the next section.
Some gate drive transformers simply deliver a voltage pulse or a series of voltage pulses to a semiconductor gate.
Gate drive transformer may be used to deliver voltage to the grids or plates of a vacuum tube or flash tube.
For more information see the overview for mosfet and igbt gate drivers product page.
In addition to the transformer it also consists of the associated reset components such as the blocking capacitor c primary resistor r gate resistor r g back to back zener diodes etc.
These devices provide electri cal pulses for turning on and off semiconductors such as high voltage power mosfets or igbts.
A gate drive circuit with very low impedance insures that the gate voltage is not exceeded in normal operation.
A special section deals with the gate drive requirements of the mosfets in synchronous rectifier applications.
A gate drive transformer is needed in a smps to control the timing of the circuit.
The basic circuit of a transformer based isolated gate drive is relatively large.
