Patent ID: 6147521
Filing Date: 2000-11-14
Classification: G01R

Abstract:
A detector of the level of supply voltage Vcc of an integrated circuit, comprising a first arm to define a first reference voltage and a second arm to define a second reference voltage, these two reference voltages varying differently as a function of a supply voltage and their curves of variation intersecting for a value of the supply voltage close to a desired threshold, and a comparator receiving the two reference voltages, wherein the first arm has a resistive divider bridge, of which an intermediate connector constitutes the first reference voltage and the second arm comprises a resistor series-connected with a native P type MOS transistor, the point of junction of this resistor and this transistor constituting the second reference voltage, the native transistor in the arm that defines the second reference voltage, in combination with the resistive divider bridge in the arm that defines the first reference voltage, provides high stability of the threshold value of supply voltage Vcc that is to be detected, the resistive divider bridge, providing very efficient control, by a simple choice of relative values of resistance, of the zone of intersection of the curves of the first and second reference voltages as a function of a supply voltage Vcc.