Power Electronics A to Z

About Power Electronics Concepts, Design & Analysis

Difference between Signal Level and Power Semiconductor Devices

What is the difference between Signal Level Semiconductor device and Power Semiconductor Device?

(or)

How the Power Semiconductor devices differ from signal level semiconductor devices?

The power semiconductor devices are not same as signal level semiconductor devices. In general, symbol of the power devices and the respective signal level devices are one and same. But their construction (structure) will differ entirely.

  • The power devices will handle very high voltages and currents. i.e. their power handling capability is very high. 
  • To meet this requirement, most of the power semiconductor devices differ in structure with their low power devices.
  • A good example for this is addition of n- region called drift region in power diode. 
  • The width of this drift region determines the breakdown voltage of the device. 
  • It makes the construction of power semiconductor devices become complex. 
  • This drift region is not available in normal signal level semiconductor devices.

Power Diode vs Signal level Diode:
The signal diode and power diode has the same symbol.
Diode_Symbol

Signal diode is a two terminal, two layer, PN Junction device.
Signal_diode_Structure

Whereas, Power diode is a two terminal,PN Junction diode which has p+, n-, n+ layers. 
Power_Diode_Structure

Signal diodes are made up of Silicon(Si) and Germanium(Ge) as well. But Power diodes are made by Silicon material only. Recently Silicon carbide(SiC) based Power diodes had entered in the market.  SiC based power diodes are having very low reverse recovery time( TRR) in terms of nano seconds.

Power BJT vs Signal Level BJT:
The structure of power bipolar junction transistor does not differ much from that of a low-power device, except that the area is greater. 

Power MOSFET vs Signal level MOSFET:
Low power MOSFETs use a later structure in which the current flow is parallel to the surface of the Si die. The Power MOSFETs usually use a vertical DMOS (Diffused MOS) structure.

Read More:
What is Power Electronics?
How Zener Diode works as a Voltage Regulator?

Your email address will not be published. Required fields are marked *

*


*