Understanding the function and structure of MOSFETs

If the transistor can be called the greatest invention of the 20th century, then there is no doubt that the MOSFET in which a great deal of credit. 1925, on the basic principles of MOSFET patents published in 1959, Bell Labs invented the principle of MOSFET based on the structural design. To this day, large to power converters, small to memory, CPU and other electronic equipment core components, none of them do not use to MOSFET. so next we understand the function of the structure of the MOSFET it! MOSFET full name is Metal-Oxide-Semiconductor Field-Effect Transistor.

1. Basic functions of MOSFETs

The basic keyword about MOSFET is - semiconductor, and semiconductor is a kind of metal material, it can conduct electricity, but in fact, it can also be insulated.MOSFET as a kind of semiconductor device, we need it to realize the function of simple is mainly to be able to ensure that the circulation of the circuit, and also be able to realize the circuit of the blocking.

2. Basic structure of MOSFETs

A MOSFET is a very versatile power device because of its low gate drive power, excellent switching speed and strong parallel operation. Many power MOSFETs have a longitudinal vertical structure, with the source and drain in opposite planes of the wafer, allowing large currents to flow and high voltages to be applied.

3. MOSFETs are mainly used as mainstream power devices in two fields

(1), the requirements of the operating frequency between 10kHz and 70kHz, while the output power to be less than 5kw in the field, in the vast majority of cases in this field, although the IGBT and power MOSFETs can achieve the corresponding function, but the power MOSFETs tend to rely on the lower switching losses, smaller size and relatively low cost to become the optimal choice, representative applications are LCD TV boards, induction cookers and so on.

(2), the requirements of the operating frequency is higher than the highest frequency that can be achieved by other power devices, the current maximum frequency is mainly in the 70kHz or so, in this area the power MOSFET has become the only choice, representative applications are inverters, audio equipment, and so on.