High-power Darlington internal circuit diagram

Published:2012/7/8 21:55:00 Author:Ecco | Keyword: High-power Darlington | From:SeekIC

Ordinary Darlington's DC magnification hFE is particularly high, so it is used normally only below 2W. When the power increases, the tube's pressure drop make temperature increase, pre- transistor leakage current will be gradually enlarged, resulting in the deterioration of the overall thermal stability. In order to overcome this deficiency, the high-power Darlington is set balanced resistor, and it is also connectrd a freewheel diode VD between C and E reverse to make over-voltage protection. When the inductive load ( relay coil ) is suddenly cut off, VD can release the reverse voltage to prevent the breakdown of the internal transistor. Figure a shows the internal circuit of high-power PNP Darlington, and Figure b shows the internal circuit of NPN type high-power Darlington.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Basic_Circuit/High_power_Darlington_internal_circuit_diagram.html

Print this Page | Comments | Reading(3)