In electrical circuits, a power semiconductor is used to control or switch current (or power) in electrical circuits. These include the power metal-oxide semiconductor field effect transistor (MOSFET), power diode, Bipolar Junction Transistor (BJT), Insulated Bipolar Transistor (IGBT), and Thyristor. The IGBT is a combination of MOSFET and BJT used in a wide range of modern electronics such as trains, VSFs (variable speed refrigerators), electric cars, VFDs (Variable Frequency Drives), stereo systems, and air conditioners use insulated-gate bipolar transistor for switching the electric power.
Uses of IGBT-Based Power Semiconductor
When used in high-power consuming circuits, the IGBT exhibits better properties than the BJT. Also, when compared to the BJTs, IGBTs have very high switching frequency. As per analyst review , IGBT provides better thermal performance efficiency due to which it is widely used in electronic items, invertors, and others. In addition, IGBTs are widely used in power electronics applications such as power supplies and converters owing to its switching speed.
IGBT-based power semiconductor is also used in a wide variety of applications ranging from consumer devices to automotive and industrial equipment. An increased adoption is also seen in IGBTs with 3-phase high output motor control inverters in EVs/HEVs, boost control in industrial power supplies & UPS, and resonance circuits for home appliances.
IGBT-Based Power Semiconductor vs. MOFSET
Generally, the gate-drive requirements of an IGBT-based power semiconductor are quite similar to that of a current rated power and comparable voltage MOSFET. This trails from the fact that both semiconductor devices have a gate structure, which is metal-oxide semiconductor (MOS) type. However, the key differences in terms of their gate drive requirements are listed below:
- Compared to the MOFSET, the IGBTs have a higher threshold gate-emitter voltage. A higher gate-emitter voltage at elevated temperatures is required to ensure that the semiconductor device remains in saturation at the provided collector current. For both of these reasons, the game-emitter voltage (VGE) applied of IGBT’s should be at least 15 V. Similarly, in case of rated MOSFETs, an applied gate-source voltage (VGS) of 10 V is usually sufficient to ensure saturation across current and temperature.
- The similarly rated IGBT-based power semiconductor tends to have a lower gate-emitter capacitance compared to the similarly rated MOSFET. Thus, IGBTs series gate turn-on resistor value is frequently preferred to be higher. This helps in minimizing the potential for resultant and ringing EMI and also limits the turn-on dt/dv.
Can Multiple IGBT-Based Power Semiconductor be Paralleled?
There are a number of modern day IGBT-based power semiconductors, such as the new Renesas Electronics Corporation’s G7H IGBTs. This semiconductor device in its nominal current range has a positive VCE vs. junction temperature dependence. Typically, these IGBT-based power semiconductors can be paralleled if a few basic precautions are taken:
- Devices should be fixed on a common heat copper/sink substrate.
- For each paralleled IGBT, the gate-drive layout is symmetrical.
- An individual and matching 2 to 4 Ω resistor should be placed in series with each gate of device. This minimizes the possibility of potential gate-voltage oscillations of in one semiconductor device coupling into another paralleled semiconductor device.
- In terms of sinking and sourcing current capability, the gate driver is strong enough to ensure fast-switching speeds. For instance, let’s pretend there are four or more paralleled IGBT-based power semiconductors, and each with a total gate charge requirement of 100 nC. Thus, it is forced that the turn-on time should be within 100ns, and the gate-drive circuit’s minimum sourcing current capability needs to be at least.
However, it is always best to contact the manufacturer of IGBT-based power semiconductors for advice for the precautions to be taken for further paralleling multiple devices.