Overvoltage detector

Abstract

An overvoltage circuit detects differences between the supply voltage from a first circuit and the operating voltage of a second circuit. The circuit may detect when the power supply value of the first circuit is below, above, or equal to the operating voltage of the second circuit. The overvoltage circuit consumes substantially zero static current and may be used in a variety of implementations.

1 . A device for comparing at least two voltages, comprising: 
 an operating voltage and a supply voltage;    a first set of at least two transistors operatively connected to receive at least one of:    the operating voltage; and    the supply voltage;    a second set of at least two transistors operatively connected to at least one of:    the first set of at least two transistors; and    ground;    wherein at least two of said first and second set of at least two transistors are operatively connected to each other; and    wherein said operatively connected transistors are capable of using substantially zero static current.    
   
   
       2 . The device according to  claim 1 , further comprising a biasing circuit.  
   
   
       3 . The device according to  claim 1 , wherein said operatively connected transistors use substantially zero static current.  
   
   
       4 . The device according to  claim 3 , wherein said transistors comprise at least one of n-channel and p-channel field effect transistors.  
   
   
       5 . The device according to  claim 4 , wherein said transistors have a substantially low threshold voltage.  
   
   
       6 . The device according to  claim 1 , wherein said transistors comprise bipolar junction transistors.