Power semiconductor is the core of electric energy conversion and circuit control in electronic devices. In essence, it realizes power switching and power conversion by using the unidirectional conductivity of semiconductor. No matter water, nuclear, thermal or wind power, or even the chemical electric energy provided by various batteries, most of them cannot be used directly. More than 75% of the electric energy application needs to be converted by power semiconductor devices before it can be used by the equipment.

A power management IC in an analog IC functions similarly to a power device in a discrete device, and the two are often integrated in a single chip, so a power semiconductor includes a power IC and a power device. The specific uses of power semiconductor are frequency conversion, phase change, voltage change, inverter, rectifier, increase, switch, etc., the related products have the role of energy saving, is widely used in automobile, communication, consumer electronics and industrial fields.

In the automobile, the input voltage of the automobile battery is 12V-36V, and the civil voltage is 220V. The process of converting the civil voltage to the input voltage is called transformer. The input current of a battery is usually direct current. The process of converting alternating current into direct current is called rectification. When the car is running, the battery continues to output direct current, while the various modules of the car need to use alternating current. The process of converting direct current to alternating current is called inverter. The output voltage of the car battery is too low to meet the needs of each module. The process of converting low voltage to high voltage is called increase. The motor in an electric car runs on three-phase electricity. First of all, the DC output of the battery becomes one-way alternating current after inverting, and the process of turning one-way alternating current into three-phase electricity is called phase alteration.