Charging the gate capacitor turns the power device ON and allows current flow between its drain and source terminals, while discharging it turns the device OFF and a large voltage is blocked across the drain and source terminals. The power device switching behavior is affected by the parasitic capacitances between the three terminals, i.e., gate-to-source (C gs), gate-to-drain (C gd) and drain-to-source (C ds) which are usually non-linear and a function of bias voltage. In order to drive these switching devices into conduction, the gate terminal must be made positive with respect to its source/emitter. To operate a MOSFET/IGBT, typically a voltage has to be applied to the gate that is relative to the source/emitter of the device. The other terminals of these devices are source and drain or emitter and collector. The gate of a MOSFET or IGBT is the electrically isolated control terminal for each device. The metal oxide semiconductor field effect transistor (MOSFET) and insulated gate bipolar transistor (IGBT) are two of the most popular and efficient semiconductor devices for medium to high power switching power supplies in most applications.
Power level requirements and switching frequency are increasing in the power electronics industry. Modern technology evolution in power electronics has generally followed the evolution of power semiconductor devices. These systems utilize many gated semiconductor devices such as ordinary transistors, FETs, BJTs, MOSFETs, IGBTs, and others as switching elements in switched-mode power supplies (SMPS), universal power supplies (UPS), and motor drives.
Power semiconductor devices are the heart of modern power electronics systems. As requirements for power electronics continue to increase, the design and performance of the gate driver circuitry are becoming ever more important.
A gate driver is a power amplifier that accepts a low-power input from a controller IC and produces the appropriate high current gate drive for a power device.
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