Patent ID: 6249162
Filing Date: 2001-06-19
Classification: G01R,H03K

Abstract:
A hysteresis circuit comprising:a voltage dividing circuit which outputs a voltage resulting from a division of a reference voltage by resistors;a comparator is provided with a) said output voltage of the voltage dividing circuit as a threshold voltage and b) an input voltage;a constant current circuit which converts a temperature-compensated reference voltage into a current using a resistor; anda switching circuit being ON and OFF are controlled according to an output of the comparator, said switching circuit being set to an ON condition where a constant current output from the constant current circuit is provided to the voltage dividing circuit and being set to an OFF condition where the constant current is not provided to the voltage dividing circuit,wherein an output voltage of the voltage dividing circuit differs between when the constant current is provided to the voltage dividing circuit and when the constant current is not provided to the voltage dividing circuit, so that the threshold level of the comparator differs; andwherein said constant current flows so that a current is drawn from a voltage divided point of the voltage dividing circuit into the constant current circuit.