A power amplifier that takes in the low power input with the help of a controller IC and generates a high current gate drive for a power device is known as a gate driver. It is utilized whenever a PWM controller is not able to provide the output current needed to drive the gate capacitance of the power device linked to it.

In the power electronic systems, the gate driver circuit is the most important part. It forms an interface between the control circuits and the high-power electronics and is utilized to drive powerful semiconductor devices. The output from the SMPS and DC-DC converters depends mainly on the gate driver's circuits. This leads to the conclusion that if the gate driver circuit is not able to drive the gate of a power device in the right manner, the output of the DC-DC converter will not be as per the design requirement. Thus, the gate driver circuit’s design is significant in the structuring of power electronic converters.

Gate Drivers Types

1. High Side Low Side Drivers – This kind of gate drivers is utilized in driving 2 switches that are connected in the bridge arrangements (both ground referenced and floating switches).
2. Low Side Drivers - This kind of gate drivers is utilized in driving ground-referenced switches.

Gate Driver Isolation

Gate drive circuits for power converters and inverters commonly require electrical isolation for both safety and functional purposes. Isolation is ordered by administrative and security accreditation organizations to forestall stun dangers. The gate drivers also help in protecting low voltage electronics from any kind of damage caused by faults on the high power side circuit. On the control side, these drivers also provide protection from error due to humans. In the system, due to the electrical separation between several functional circuits, a direct conductional path between them is prevented. Not only this, but it also enables individual circuits to have different ground voltage. Power and signals can still pass between isolated circuits with the help of capacitive, optical, or inductive methods.

Several applications of power devices need an isolated gate drive circuit. For instance, in power converter topologies like the two-switch forward, buck, active-clamp forward, full-bridge and, half-bridge, both the high as well as low switches are present because low side drivers cannot be utilized directly for driving the higher power equipment. This equipment needs an isolated gate driver because the emitter and source of the upper devices are not sitting at the ground potential.

Two things are required for driving high side switches:

• Level shifter - to pass on the PWM control signal to the floating driver circuitry.
• Floating Supply – to support any circuitry by providing power with this floating midpoint potential.

Techniques of Isolation

Generally, there are two most common methods to actualize isolated gate drivers:

• Optical – Takes place with the help of Opt coupler.
• Magnetic – Takes place with the help of Gate drive transformers.

This was all we have regarding Gate drivers. Hope you liked going through it. Brands that manufacture them are TE Connectivity, ITT, and Molex. Make sure to visit them using the links as provided.

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