As the most fundamental building blocks of electronic systems, semiconductor power devices play a crucial role in various industries, including automotive electronics, consumer electronics, network communications, electronic equipment, aerospace, military equipment, instrumentation, industrial automation, and medical electronics. In this article, Chendaxing will introduce the definition and classification of power devices.
How Are Discrete Power Semiconductor Devices Defined?
Power semiconductor discrete devices (Power Electronic Devices), also known as power electronics devices, refer to electronic devices that can be directly used in main circuits to process electrical energy, thereby achieving power conversion or control. Their functions are primarily categorized into power conversion, power amplification, power switching, circuit protection, and rectification.
Power semiconductor discrete devices can be broadly classified into two major categories: power semiconductor discrete devices (including power modules) and power semiconductor integrated circuits (Power ICs). Among these, power semiconductor discrete devices refer to semiconductor devices designed to perform a specific basic function and cannot be further subdivided functionally.
In 1957, General Electric (GE) in the United States developed the world's first industrial-grade thyristor, marking the birth of discrete power semiconductor devices. The development of discrete power semiconductor devices has gone through a first stage centered on thyristors, a second stage represented by MOSFETs and IGBTs, and is now entering a new stage centered on wide-bandgap semiconductor devices.
How Are Discrete Power Semiconductor Devices Classified?
Based on device structure, they are classified into diodes, power transistors, thyristors, and others. Among these, power transistors are further divided into bipolar junction transistors (BJTs), junction field-effect transistors (JFETs), metal-oxide-semiconductor field-effect transistors (MOSFETs), and insulated-gate bipolar transistors (IGBTs).
Based on power handling capability, they are classified into low-voltage, low-power discrete semiconductor devices; medium-power discrete semiconductor devices; high-power discrete semiconductor devices; and high-voltage, ultra-high-power discrete semiconductor devices.
Based on the nature of the signal applied between the control terminal and the common terminal by the drive circuit (excluding power diodes), they can be classified into current-driven and voltage-driven types.
Current-driven: Power semiconductor discrete devices that are turned off by injecting or extracting current from the control terminal.
Voltage-driven: Power semiconductor devices that are turned on or off by applying a specific voltage signal between the control terminal and the common terminal.
Based on the degree to which the control circuit signal controls the device, they can be classified as uncontrolled, semi-controlled, and fully controlled.
Uncontrolled devices: Power semiconductor discrete devices whose on/off states cannot be controlled by a control signal; representative devices include power diodes.
Semi-controlled devices: Power devices whose conduction can be controlled by a control signal but whose turn-off cannot be controlled; representative devices include thyristors and most of their derivative devices.
Fully Controlled Devices: Discrete power semiconductor devices in which control signals can regulate both turn-on and turn-off; representative devices include insulated-gate bipolar transistors (IGBTs), power field-effect transistors (FETs), and gate-turn-off thyristors;
Based on the involvement of the two types of charge carriers-electrons and holes-in the device's conduction, power semiconductor discrete devices can be classified into unipolar devices, bipolar devices, and composite devices.
Unipolar devices: Power semiconductor discrete devices in which only one type of charge carrier (electrons or holes) participates in conduction;
Bipolar devices: Power semiconductor discrete devices in which both electrons and holes participate in conduction;
Composite devices: Discrete power semiconductor devices formed by the integration of unipolar and bipolar devices;
Based on the substrate materials used in power semiconductor devices, existing discrete power semiconductor devices can be classified into three generations:
First-generation semiconductor materials are primarily represented by germanium (early products, now uncommon) and silicon.
Second-generation semiconductor materials are primarily compound semiconductor materials, such as gallium arsenide (GaAs) and indium phosphide (InP).
Third-generation semiconductor materials are primarily wide-bandgap semiconductor materials, such as silicon carbide (SiC) and gallium nitride (GaN).