SINGLE_COMPARATOR_WINDOW_DETECTOR

Published:2009/6/18 3:54:00 Author:May | From:SeekIC

Simply by adding two steering diodes, a window detector can be built using only a single com-parator. The detector performs well for windows of about 1 V or greater, but it isn't suitable where extreme precision is required because the forward drops of the diodes vary.In the basic circuit, two resistive dividers set threshold voltage levels at both the inverting and noninverting inputs of the comparator by dividing the reference voltage. The input voltage is steered to the appropriate comparator input by diodes CR1 and CR2.When the input voltage is within the window, neither diode conducts, and the comparator is bi-ased for a high output. When the input goes above the window, CR2 conducts and pulls the inverting input high, causing the comparator output to go low. When the input voltage goes below the window, CR1 conducts, pulling the noninverting input low, again causing the comparator output to go low. The source resistance of Vinmust be low compared to the equivalent parallel resistance of each divider.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Measuring_and_Test_Circuit/SINGLE_COMPARATOR_WINDOW_DETECTOR.html

Print this Page | Comments | Reading(3)