These days, the spotlight often shines on devices utilizing cutting edge wide bandgap (WBG) materials like silicon carbide (SiC) and gallium nitride (GaN). Amidst this focus, it's convenient to overlook that merely a few years ago, the insulated gate bipolar transistor (IGBT) stood as the preferred solution for numerous applications.
What Are IGBT Transistors?
IGBTs represent a prominent category of power electronic devices extensively applied across various power electronics applications. Functioning as a hybrid of two distinct transistor types, namely the BJT and MOSFET, IGBTs amalgamate the high input impedance and rapid switching capabilities of MOSFETs with the low saturation voltage of BJTs, resulting in a superior transistor configuration.
The tranzistor IGBT stands on the verge of being recognized as an almost perfect switch. Nevertheless, one might wonder about the distinctions between an IGBT and a MOSFET. What benefits does an IGBT provide, and what is its operational mechanism?
In communities dedicated to power electronics, inquiries like the following are commonplace: "I'm tasked with designing an H-bridge for motor control with specifications including a voltage of 320 V, current of 2 A, and a switching frequency of 30 kHz. To err on the side of caution, I'm in search of a switch with a 600 V blocking capability. However, I'm unsure whether to opt for MOSFET or IGBT. Any guidance on the criteria for making an informed selection?"
In this scenario, the decision isn't straightforward, given the absence of key parameters. Both 600 V MOSFET and 600 V IGBT solutions could be considered for the specified requirements. Crucial but unmentioned criteria in the query revolve around size, efficiency, and cost targets.
The Insulated Gate Bipolar Transistor (IGBT) has emerged as the predominant power electronic component in industrial applications, playing a central role in inverters for diverse electric drives, battery chargers, as well as solar and wind power plants. But what sets this component apart? What are its strengths, and what challenges must be addressed when employing this technology? The answers to these questions lie within the intricacies of the technology itself.
The Wide Portfolio of Available Parts
From controlling the speed of low power compressors in refrigerators to propelling traction drives in railways, the IGBT insulated gate bipolar transistor has asserted its dominance over the past few decades. The user now has a plethora of options, ranging from discrete designs with a 300 V capacity to robust power modules supporting up to 6500 V. The current carrying capability of a single transistor spans from a few amps to several kilo-amps.
In addition to the well established TO-package series, surface mount device (SMD) components are available, complemented by power modules designed to meet the most demanding power requirements. Depending on the power specifications, soldering or press-in connectors are utilized, while applications with currents surpassing 200 A typically necessitate screw-type terminals.
IGBT: A Simple Technology
At its core, the primary function of an IGBT is the rapid and efficient switching of electric currents, aiming to minimize switching losses. The nomenclature "Insulated Gate Bipolar Transistor" indicates that an IGBT is essentially a bipolar transistor featuring an isolated gate structure, where the gate functions as a MOSFET. Consequently, the IGBT seamlessly integrates the benefits of a bipolar transistor, including high current-carrying capabilities and high blocking voltages, with the capacitive and nearly zero-power-based control attributes of a MOSFET.
The schematic provides a broad overview of the structure, but in reality, the technical design doesn't rely on two separate entities. The comprehensive functionality is the result of integrating the structure at the chip level.
In this integrated design, the MOSFET serves as the gate structure, leading to the absence of a distinct Base for the bipolar transistor. Instead, the device is now interconnected through the Collector, Gate, and Emitter.
IGBT: Cleverly Integrated in Power Modules
In many instances, a singular switch proves insufficient for developers constructing a design. Typically, within a frequency converter, two units are requisite. Initially, the supplied voltage drawn from the grid undergoes rectification, and the DC-voltage level may need adjustment or stabilization. Subsequently, an inverter is employed to transform the DC-link voltage into the desired AC system, which may differ from the supplying grid in terms of frequency, amplitude, and even the number of phases.
If the application doesn't require regenerative operation, a simple diode rectifier can be selected. The energy from the application results in an elevation of the DC-link voltage. In this scenario, a break chopper is incorporated. In the event of surplus energy, it provides a pathway for safely managing energy by converting it into heat.
Manageable Thermal Characteristics
Contemporary IGBTs closely emulate the characteristics of an ideal switch. This ideal switch is defined by zero current when in the off state and zero voltage across the device when in the on state. Consequently, an ideal switch incurs no losses and, by extension, generates no heat. While modern IGBTs achieve efficiency levels exceeding 99% for each individual switch, it is crucial not to overlook the significance of thermal management in ensuring optimal performance.
Trench Gate Field Stop Construction
Within the realm of IGBTs, a design that elevates the performance of these devices to another tier is the trench gate field-stop (TGFS) architecture.
In TGFS construction, trenches are intricately etched into the silicon of the device and subsequently filled with a gate material, typically polysilicon. This trench-gate structure supersedes the planar gate structure present in conventional IGBTs, enhancing channel density and consequently reducing the on-state voltage drop, thereby improving the device's conduction characteristics.
The "field-stop" attribute in TGFS pertains to an additional N-layer situated near the collector. This N-layer induces a rapid decline in the electric field within the adjacent N-drift layer upon reaching the P+ collector.
The integration of trench-gate and field-stop technologies in TGFS IGBTs yields devices that surpass the performance of traditional planar IGBTs. They demonstrate reduced conduction and switching losses, leading to heightened overall efficiency while maintaining a robust breakdown voltage.
Check out all of igbt insulated gate bipolar transistor or mosfet transistor options to find what you need and contact GUOYUAN ELECTRONICS for more imformation.
Discrete Semiconductor Products
Discrete Semiconductor Products
Motors, Actuators, Solenoids and Drivers
Motors, Actuators, Solenoids and Drivers
RF/IF and RFID
RF/IF and RFID
Integrated Circuits (ICs)
Integrated Circuits (ICs)
Inductors, Coils, Chokes
Inductors, Coils, Chokes
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