Glossary
Alternating current (AC)
The alternating current (AC) is an electric current type that periodically reverses direction, flowing first in one direction and then in the opposite direction during a given interval. It is crucial for efficient energy transmission over long distances and enables the use of transformers to adjust voltage levels for various applications.
Aluminium oxide (Al₂O₃)
Aluminium oxide (Al₂O₃) is a ceramic material with a high thermal conductivity and good electrical insulation properties. It is often used in power modules, particularly for substrates parts due to its high electrical insulation capacity and thermal conductivity.
Aluminium nitride (AlN)
Aluminium nitride (AlN) is an high-performance ceramic material. Its relevance for power modules lies in its ability to efficiently dissipate heat while maintaining electrical isolation, making it ideal for high-power electronic applications.
Bare die
A bare die refers to a small, unencapsulated block of semiconductor material that has been cut from a wafer and contains integrated circuits or transistors.
Break chopper (BRC)
A break chopper (BRC) is a device used in power electronics to quickly interrupt the current flow in a circuit, effectively controlling the power delivered to a load. Its relevance for power modules lies in its ability to enhance the efficiency and reliability of power conversion systems by providing rapid response to changes in load conditions.
Converter inverter break (CIB)
A CIB module integrates three major power conversion stages into a single housing: converter, inverter, and brake (chopper). The rectifier establishes the DC link voltage, while the inverter generates three‑phase AC output voltage for the load. The integrated brake chopper provides controlled dissipation of regenerative energy to protect the DC link from overvoltage during deceleration or load‑transient conditions.
Coefficient of thermal expansion (CTE)
The coefficient of thermal expansion (CTE) measures how much a material expands or contracts in response to changes in temperature. In power modules, CTE is crucial because mismatches in thermal expansion between different materials can cause mechanical stress, leading to failure or reduced reliability of the module over time.
Direct current (DC)
The direct current (DC) is an electrical form in which electric charge flows in a single, unidirectional path. Unlike alternating current, DC maintains a constant polarity and typically a steady voltage level, making it suitable for powering electronic circuits and energy‑storage systems.
Direct copper bonding (DCB)
Direct copper bonding (DCB) is a substrate technology in which copper layers are permanently bonded to a ceramic base, forming a robust platform for high‑power semiconductor devices. The process creates a thermally conductive, electrically insulating structure suitable for managing substantial heat and current levels.
Double-sided cooling (DSC)
A double-sided cooling is a thermal management technique where heat is dissipated from both the top and bottom surfaces of a component, improving overall heat dissipation efficiency. In power modules, this is crucial for enhancing performance, reliability and power density by effectively managing high heat loads, reducing the need for large cooling systems.
Electromagnetic compatibility (EMC)
The electromagnetic compatibility (EMC) is the ability of electrical devices to operate without interfering with other equipment through electromagnetic disturbances and to withstand such interference themselves.
Electromagnetic interference (EMI)
The electromagnetic interference (EMI) is the disruption of electrical signals caused by external electromagnetic fields or noise from nearby electronic devices.
EOFF
The energy [J] dissipated during turn-off phase on a power device (EOFF) refers to the amount of energy lost as heat when a power device, such as a transistor, switches from an "on" to "off" state. In power modules, minimizing EOFF is crucial to improve efficiency and reduce thermal management challenges, particularly in high-frequency or high-power applications.
EON
The energy [J] dissipated during turn-on phase on a power device (EON) refers to the energy lost as heat when a power device switches from an "off" to "on" state. In power modules, reducing EON is essential for improving efficiency and ensuring reliable operation, especially in high-speed switching applications where energy losses can accumulate significantly.
Field-effect transistor (FET)
A field-effect transistor (FET) is a type of transistor that controls the flow of current through a semiconductor channel using an electric field applied to its gate terminal. FETs are widely used in power modules due to their high efficiency and fast switching capabilities.
Freewheeling diode (FWD)
A freewheeling diode (FWD) is a diode placed across an inductive load in a circuit to provide a path for current when the power source is switched off, preventing voltage spikes. In power modules, FWDs play a critical role in protecting switching devices like transistors from damage due to the inductive load, enhancing the module's overall efficiency and reliability.
Gallium nitride (GaN)
Gallium nitride (GaN) is a wide-bandgap semiconductor material known for its high efficiency and fast switching capabilities. It is particularly relevant in power modules because it enables smaller, more energy-efficient power converters, improving performance in high-frequency applications such as data centers and renewable energy systems.
H6.5
The H6.5 topology is a transformer-less single phase inverter architecture commonly used in grid connected photovoltaic (PV) systems. It is an evolution of the conventional HERIC topology, designed to further reduce switching losses and leakage current, while maintaining high efficiency and a simple modulation/control strategy.
Highly efficient and reliable inverter concept (HERIC)
It is a topology used in transformer-less single phase inverter architecture employed for grid connected photovoltaic (PV) systems. It was developed to achieve high efficiency, low leakage current and reduced switching losses, while maintaining regulatory compliance for transformer-less operation.
I²t (current squared through time)
I²t refers to the cumulative effect of electric current squared over a given period of time. It is commonly used to quantify the thermal energy generated in electrical components due to resistive heating.
Ic (collector current [A])
A collector current (DC current) [A] refers to the amount of direct current flowing through the collector terminal of a transistor in an electronic circuit.
ICRM (repetitive peak collector current)
A repetitive peak collector current (ICRM) refers to the maximum current that can flow through the collector of a power semiconductor device during repetitive pulses, without exceeding its thermal or electrical limits.
Surge current in forward conduction (IFSM)
An IFSM refers to the maximum peak current that a power semiconductor device, such as a diode or thyristor, can conduct for a short time without being damaged.
Insulated‑gate bipolar transistor (IGBT)
An IGBT is a semiconductor switching device that combines the high‑input‑impedance control characteristics of a MOSFET with the high‑current and low‑loss conduction capabilities of a bipolar transistor.
Intelligent power module (IPM)
Intelligent power module (IPM) integrates power switches, gate drives and protection circuits into a single housing. It is a smart version of a PIM. The rectifier establishes the DC link while the inverter delivers a regulated three‑phase AC output to the load. Built‑in gate drivers, protection logic, and sensing functions manage switching events and safeguard against overcurrent, short‑circuit and other faults.
Irrm (peak reverse recovery current)
A peak reverse recovery current is the maximum current that flows in the reverse direction when a diode or similar device switches from conducting forward current to reverse blocking.
Junction field‑effect transistor (JFET)
An JFET is a voltage‑controlled semiconductor device that regulates current flow through a reverse‑biased p‑n junction. It operates using an electric field applied to its gate terminal, which modulates the conductivity of a narrow semiconductor channel.
Low voltage ride through (LVRT)
A LVRT refers to the capability of power-generating devices, such as solar inverters, to remain connected and operational during short dips in grid voltage, ensuring grid stability.
Modified neutral point clamped (MNPC)
The MNPC topology is an evolution of the classic NPC three-level inverter. It provides low-distortion output waveforms, reduced dv/dt stress and enhanced thermal distribution by minimizing the number of components in the current path. Its actively controlled neutral‑point connection enables better voltage balancing and supports advanced modulation schemes.
Metal-oxide semiconductor field-effect transistor (MOSFET)
A MOSFET is a voltage‑controlled semiconductor device used to switch or amplify electrical signals. It operates by using an electric field applied to an insulated gate structure to modulate the conductivity of a semiconductor channel.
Maximum power point (MPP)
The maximum power point (MPP) is the precise operating condition at which a power system, like a solar panel, generates its highest possible power output.
Neutral point clamp (NPC)
The NPC (neutral point clamp) topology is a three-level inverter structure that lowers harmonic distortion, decreases filter requirements and improves overall power quality compared to two‑level inverters. Its diode‑based clamping structure supports efficient medium‑frequency switching, enhances reliability through passive voltage balancing and enables stable operation across a wide range of load conditions.
Negative temperature coefficient (NTC)
The negative temperature coefficient (NTC) refers to a property in which a material's electrical resistance decreases as its temperature increases.
Printed circuit board (PCB)
A printed circuit board (PCB) is a flat board that electrically connects and mechanically supports electronic components using conductive pathways etched onto a non-conductive substrate.
Phase-change material (PCM)
A phase-change material (PCM) is a substance that absorbs or releases heat as it changes between solid and liquid states, allowing it to regulate temperature by storing thermal energy. In power modules, PCMs are relevant because they help dissipate excess heat, enhancing performance and extending component lifespan by preventing overheating.
Power factor correction (PFC)
Power factor correction (PFC) is the process of adjusting the power factor of an electrical system to make it closer to 1, which improves the efficiency of power usage by reducing the phase difference between voltage and current.
Power integrated module (PIM)
A power integrated module (PIM) is a highly integrated power module that combines several functions into a single module. By combining components like rectifiers, inverters and brake circuits, a PIM simplifies design, minimize footprint and improve thermal performance.
Positive temperature coefficient (PTC)
A positive temperature coefficient (PTC) refers to a material property where electrical resistance increases as the temperature rises.
Ptot
Ptot (total power dissipation) refers to the total amount of energy lost as heat in a system or component during its operation. In power modules, it is critical as excessive dissipation can reduce efficiency and lead to overheating, which may damage components and compromise system reliability.
Pulse-width modulation (PWM)
The pulse-width modulation (PWM) is a technique used to control the amount of power delivered to an electrical device by varying the width of the voltage pulses in a periodic signal.
Rds(on)
Rds(on) refers to the drain‑to‑source on‑resistance of a MOSFET when it is in the fully conducting state. It represents the effective resistance between the drain and source terminals once the device is turned on and operating within its specified gate‑drive conditions.
Registration, evaluation, authorization and restriction of chemicals (REACH ), EU 1907/2006
REACH under EU regulation 1907/2006 is a framework ensuring the safe use of chemicals by requiring manufacturers and importers to assess and manage chemical risks. It is relevant for power modules as it ensures compliance with safety standards, reducing the risk of hazardous substances in their components and promoting environmental and user safety.
Gate circuit resistance (RG)
The gate circuit resistance (RG) refers to the resistance in the gate drive circuit of a power semiconductor device, which influences the switching speed and stability of the device.
Internal gate resistance (RGint)
The internal gate resistance (RGint) is the inherent resistance within a power module's gate circuit that influences the speed of switching and energy losses during operation. It is crucial for power modules as it impacts switching performance, thermal management and overall system efficiency.
Restriction of certain hazardous substances (RoHS), EU 2011/65
The restriction of certain hazardous substances (RoHS) directive (EU 2011/65) limits the use of specific hazardous materials, such as lead and mercury, in electrical and electronic equipment to reduce environmental and health risks. Power modules must comply with RoHS to ensure they are safe, environmentally friendly, and marketable within the European Union.
Thermal resistance (Rth)
The thermal resistance (Rth) is a measure of a material's or component's ability to resist the flow of heat, typically expressed in °C/W. In power modules, it is crucial for determining the efficiency of heat dissipation, impacting the module's reliability and performance under high power loads.
Silicon controlled rectifier (SCR)
A silicon controlled rectifier (SCR), also known as a thyristor, is a semiconductor device that functions as a switch to control high-power electrical currents by latching into conduction when triggered.
Silicon (Si)
Silicon (Si) is a chemical element and semiconductor material widely used in electronics due to its excellent ability to control electrical conductivity.
Silicon carbide (SiC)
Silicon carbide (SiC) is a hard, thermally stable semiconductor material with excellent electrical properties, widely used in high-performance electronic applications. Its high efficiency, thermal conductivity and ability to withstand high voltages make it crucial for improving the performance and energy efficiency of power electronics applications.
Switching mode power supplies (SMPS)
Switching mode power supplies (SMPS) are energy-efficient electronic power converters that use high-frequency switching to regulate and convert electrical power.
Single-sided cooling (SSC)
A single-sided cooling (SSC) is a thermal management technique where heat is dissipated from only one side of an electronic component, such as a power module. It is relevant to power modules as it simplifies design and reduces manufacturing costs while maintaining effective heat dissipation in compact systems.
Ambient temperature (Ta)
An ambient temperature (Ta) is the temperature of the surrounding environment in which a device or system operates.
Turn-off delay time (td(off))
A turn-off delay time (td(off)) is the interval between the removal of the gate signal and the start of a power device transitioning from the on-state to the off-state.
Turn-on delay time (td(on))
A turn-on delay time (td(on)) refers to the time interval between the application of the input signal and the moment the device or power module begins to conduct.
Fall time (tf)
A fall time (tf) refers to the time it takes for a signal or voltage to decrease from a high value to a low value, typically measured between 90% and 10% of its peak amplitude.
Thermal interface material (TIM)
A thermal interface material (TIM) is a substance applied between two surfaces to enhance heat transfer by filling microscopic gaps and improving thermal conductivity. In power modules, TIM is crucial for efficiently dissipating heat from components like semiconductors, ensuring optimal performance and preventing overheating.
Junction temperature (tj)
A junction temperature refers to the temperature of the semiconductor material inside a component, such as a transistor or diode, at its hottest point. For power modules, managing the junction temperature is critical because excessive heat can degrade performance, shorten lifespan and potentially cause failure of the module.
Maximum junction temperature (tj,max)
The maximum junction temperature refers to the highest temperature that the semiconductor junction of a device can safely reach without risking damage or failure. In power modules, maintaining the junction temperature below this limit is crucial to ensure the reliable performance and longevity of the module under high power conditions.
Turn-off time (toff)
A turn-off time (toff) refers to the duration it takes for a power transistor to transition from an on-state to an off-state after a signal is applied.
Turn-on time (ton)
A turn-on time refers to the time it takes for a power device, such as a transistor to fully transition from its off-state to its on-state after a control signal is applied.
Rise time (tr)
A rise time is the duration it takes for a signal to transition from a specified low value to a high value, typically measured from 10% to 90% of its maximum amplitude.
Reverse recovery time (trr)
A reverse recovery time is the duration it takes for a diode to switch from conducting in the forward direction to blocking in the reverse direction after the current flow is interrupted. In power modules, a shorter reverse recovery time reduces losses, enhances efficiency, and minimizes the generation of unwanted heat, which is crucial for high-speed switching applications.
Short circuit interval (tsc)
A short circuit interval refers to the duration during which a short circuit is detected and cleared in an electrical circuit to prevent damage. In power electronics devices, managing the short circuit interval is critical for protecting the components from overheating or failure due to prolonged short circuits.
Uninterruptible power supply (UPS)
A UPS is an electrical equipment designed to provide immediate backup power to connected devices when the primary power source becomes unavailable or unstable.
Collector-emitter voltage (VCES)
The collector-emitter voltage (VCES) is the voltage difference between the collector and emitter terminals of a transistor, typically used to control the flow of current in the device.
Gate-emitter voltage [V] (VGES)
The gate-emitter voltage [V] refers to the voltage difference between the gate and emitter terminals of a transistor, typically a field-effect transistor (FET), which controls its switching behavior.
Zero current switching (ZCS)
A zero current switching (ZCS) is a technique in power electronics where the switch is turned on or off when the current through it is zero, reducing switching losses and electromagnetic interference.
Transient thermal impedance (Zth)
A transient thermal impedance is a measure of how a power module's temperature responds to rapid changes in power dissipation over time. It is crucial for understanding the thermal performance and ensuring the reliability of power modules during dynamic operation, preventing overheating and failure.
Zero voltage switching (ZVS)
A zero voltage switching (ZVS) is a technique in power electronics where the switch turns on or off when the voltage across it is zero, minimizing switching losses.