Gate Drive Transformer Tutorial

Driver ics typically come in an 8 pin dip soic or power tssop package.

Gate drive transformer tutorial. The gate drive transformer provides both the floating supply as well as the level shifting of the switching signal to the power semiconductor thereby eliminating a separate floating power supply. Gate drive ics the simplest way to drive a gate is to use a gate drive ic. This ic contains the necessary circuitry to source and sink high current pulses and usually simply requires a power supply and a logic level input. Gate drive transformers are not suitable for dc and can be used only for ac signals time varying signals.

The larger ones may come in a 5 pin to 220 package. 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. A gate drive transformer is needed in a smps to control the timing of the circuit. They also are used for voltage isolation and impedance matching.

It can be used to directly drive the power switch mosfet igbt gates or it can be used to just isolate the control signal which is then applied to a gate driver ic. Designed is the gate drive transformer in a switch mode power supply smps. This gate drive transformer gdt circuit allows the drive signal to the mosfet to range from 50 down to 0 while still offering a fast turn off that cannot be accomplished with a simple load. A special section deals with the gate drive requirements of the mosfets in synchronous rectifier applications.

Large duty ratios more than 50 cannot be handled by the transformer without being saturated due to the transformers operating only at ac signals the core flux must be reset each half cycle in order to maintain a volt second balance unless ac coupling capacitors and zener diodes are employed.