What is a Power Semiconductor?
Sanken Electric is a manufacturer specialized in power electronics and power semiconductors.
Power electronics runs electronic devices efficiently and very accurately by control and conversion of electric power. The term refers to both technologies and products that involve two overlapping fields of "power" and "electronics".
The applications are found in a diverse array of industries ranging from home appliances and audio visual equipment, to automobiles which are increasingly becoming electronized.
The key device in power electronics is the power semiconductor.
Power Electronics in Our Everyday Lives
Electricity Generated at a Power Station Cannot be Used as Is
Hundreds of thousands of volts of electricity generated at power stations are converted into 100V and/or 200V* alternating
currents (AC) by substations and supplied to households, offices, facilities, and other destinations. These currents are,
however, unable to run home appliances and office automation equipment as is. For instance, TVs and airconditioners consist of microcontrollers
and other electronic components which run at 3V or 5V direct current (DC). Power semiconductors installed in the power supplies of various equipments convert the electricity delivered to the outlet in the form of 100V or 200V AC currents into DC currents, which is then converted into the voltage required by each equipment.
* Voltage varies by country.
What is a Power Semiconductor?Power semiconductors control motors and lighting systems and convert electric power.
Their characteristic lies in that they handle high voltages and large currents.
LSIs such as microcomputers and memories are well known semiconductors. These are designed to perform computations and memorization tasks, while power semiconductors control power supplies (electric power) and supply power to run motors, charge batteries, or run microcomputers and LSIs by performing AC to DC conversions, reducing voltage to appropriate operating level such as 5V or 3V.
■ Tasks Performed by Power Semiconductors
■ Main Types of Power Semiconductors
Diodes One-way Flow (Rectification), Yet with a Wide Range of Applications
Electricity flows from high voltage (+) to
low voltage (-), just like water.
For instance, prepare two electric wires, place a
diode and electric bulb half way up each wire, and
connect these wires to batteries, as shown in the
illustration on the right. In the case of ❶, electricity
flows through the wire and the bulb lights up. In
the case of ❷, however, no electricity flows
through the wire
This is because the diode is a semiconductor which serves as a tap valve that allows electricity to flow in only one direction.
Its real task is "rectification", converting AC to DC. Diodes designed for this purpose are called rectifier diodes (rectifer elements). Currents supplied to households are AC currents. However, DC currents are required to run electronic equipment circuits, and it is the rectifier diodes that perform the AC to DC conversions.
Sanken Electric manufactures various diodes, from rectification and high speed switching types, to compact schottky diodes with small voltage drop.
Transistors Carries Heavy Loads with Three Legs (Amplification & Switches)
Transistors are elements which are the basis of electronic circuits. They perform amplification and switching operations Amplification is to convert a small amount of electricity to a large amount of electricity. For example, amplification is the process of turning a small sound from earphones into a loud sound that can be heard on speakers. Switching is the act of turning ON and OFF large current and high voltage electricity with only a small amount of electric power, and is used to drive display screens, and to run motors, etc. MOSFETs and IGBTs are also a type of transistors.
ICs (Integrated Circuit) A Single Chip Performing Multiple Tasks
Integrated circuits (ICs) combine many diodes, transistors, and other circuit elements onto a single silicon chip. When a large number of diodes, transistors, and other circuit elements are placed on a single silicon chip, they are called large-scale integrated circuits (LSIs). These circuits perform rectification, amplification, memorization tasks, arithmetic operations, etc.