The role of transistor switches

(1) Control high power
Today's power transistors can control hundreds of kilowatts of power. There are many advantages to using power transistors as switches, mainly;
(1) It is easy to turn off and requires less auxiliary components,
(2) The switch is fast and can work at a very high frequency,
(3) Available devices with withstand voltage range from 100V to 700V, everything.
A few years ago, the switching capability of transistors was less than 10kW. Currently, it can control up to hundreds of kilowatts of power. This is largely due to the combined efforts of physicists, technicians and circuit designers to improve the performance of power transistors. like
(1) The increase in the effective chip area of the switching transistor,
(2) Technical simplification,
(3) Recombination of transistors – Darlington,
(4) Advances in base drive technology for high-power switches.

(2) Transistor power switch directly working on rectified 380V mains
Both transistor compounding (Darlington) and paralleling are effective ways to increase the switching capability of transistors.
In such high power circuits, the main problem is the wiring. The very high switching speeds can generate relatively high interference voltages on very short connecting lines.

(3) High performance due to simple and optimized base drive
Today's base drive circuits not only drive the power transistors, but also protect the power transistors, which is called “non-centralized protection” (as opposed to centralized protection). The functions of the integrated drive circuit include:
(1) Turn on and off the power switch;
(2) Monitor the auxiliary power supply voltage;
(3) Limit the maximum and minimum pulse width;
(4) Thermal protection;
(5) Monitor the saturation voltage drop of the switch.

Summarized by Easybom.