IGBT (Insulated Gate Bipolar Transistor) Supplier and Distributor in the United States

The Insulated Gate Bipolar Transistor (IGBT) is a composite, fully controlled, voltage-driven power semiconductor device composed of a BJT (bipolar junction transistor) and a MOSFET (insulated gate field-effect transistor). It combines the advantages of both devices: the high input impedance and low on-voltage drop of the GTR (Gate Turn-Off Thyristor) and the fast switching speed and low drive power of the MOSFET. While the GTR offers reduced saturation voltage and high current-carrying density, it requires a large drive current; conversely, the MOSFET has low drive power and fast switching speed but suffers from a higher conduction voltage drop and lower current-carrying capacity. The IGBT integrates these advantages, achieving low driving power and reduced saturation voltage. It is highly suitable for converter systems with DC voltages of 600 V and above, including applications such as AC motors, frequency converters, switching power supplies, lighting circuits, traction drives, and more.

The IGBT is a typical bipolar-MOS composite power device that combines power MOSFET process technology to integrate the power MOSFET and the power GTR on the same chip. This device features high switching frequency, high input impedance, good thermal stability, a simple drive circuit, low saturation voltage, and high current capacity. It is widely used as a power device in industrial control, power electronics systems, and other fields—for example, servo motor speed regulation and variable frequency power supplies. To ensure that the systems designed operate safely and reliably, protecting the IGBT is especially important.

Currently, in the use and design of IGBTs, a widespread design approach is adopted that requires large safety margins, resulting in bulky systems that still struggle to resist external interference and various failures caused internally by the system itself. Shunlei Electronics leverages its production and design advantages in the semiconductor field and, combining the characteristics of transient suppression diodes, has overcome this design bottleneck by integrating internal and external systems based on studies of the IGBT failure mechanism. This article will break through traditional protection methods and discuss solutions for IGBT system circuit protection design.

IGBT failure scenarios: Failures may arise internally, such as from distributed stray inductance within the power system, motor-induced electromotive forces, and load mutations that cause overvoltage and overcurrent; or externally, such as grid fluctuations, power line induction, surges, and similar disturbances. Ultimately, IGBT failures are mainly caused by overvoltage and overcurrent at the collector-emitter terminals and overvoltage/overcurrent at the gate.

IGBT failure mechanism: The IGBT can be short-circuited due to these causes, generating large transient currents—especially when the current change rate (di/dt) during turn-off is too high. The presence of leakage and lead inductances can cause overvoltage at the IGBT collector, which produces a latch-up effect inside the device and leads to device lock failure. Additionally, excessive overvoltage can cause device breakdown. Due to these factors, the IGBT may enter an amplification region, increasing switching losses.

Traditional IGBT failure prevention mechanisms: Minimize wiring inductance and capacitance in the main circuit to reduce turn-off overvoltage; install a freewheeling diode between the collector and emitter; connect RC or RCD snubber circuits; select appropriate series impedance on the gate according to circuit capacity; and connect a Zener diode in parallel to prevent gate overvoltage.