Introduction: Proper GDT (Gate Drive Transformer) Construction (Half / Full H-Bridge)

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It's important to use GDT for high voltage projects like SSTC (Solid State Tesla Coil)., DRSSTC (Dual Resonant Solid State Tesla Coil), or you can even use it for flyback transformer or induction heater. It also allows you to drive High Side N-Ch MOSFET without specialized high side MOSFET driver.

Supplies

1x Toroid Core (Buy from reputable sources like Digikey / Mouser)

1x Cat 5 cable

2-3 zip ties (optional)

Step 1: Choose Material for Toroid

Ok materials:

3C11, 3E6, 3E12, 3E10, 3E15, 3E25, 3E26, 3E27, 3E65

Ideal materials:

PC40, PC200

N27, N30, N35, N41, N49, N51, N72, N87, N88, N92, N95, N96, N97

T35, T37, T37, T38, T46, T57, T65, T66

3C90, 3C91, 3C92, 3C93, 3C94, 3C95, 3C96, 3C97

Step 2: Calculate Number of Turns

Example calculation:

Outer_Diameter = 41.8mm, Inner_Diameter = 26.2mm, Length = 12.5mm

Area = Length * 0.5 * (OD-ID) * Pi/4 ‎ = 76.576


Flux Density @ (25C, 100C)

Flux N97 ‎ = 510, 410 mT


flux = 0.5 T

freq = 25 kHz ==>> time = 500 / freq ‎ = 20 us

volts = 24


Turns = ( time * volts ) / ( flux * area ) ‎ = 12.537 turns

Step 3: Winding and Configuration

Wind the number of turns on toroidal core. Taking above example: 13-15 turns is ok. Less than 12 turns is not ok.

Wind the wire tightly. It’s important to use twisted cable to keep league inductance low.


Configure the wire for Half/Full H-Bridge configuration and connect them to appropriate pins of MOSFETs / IGBTs