Patent ID: 7646190
Filing Date: 2010-01-12
Classification: G01L

Abstract:
1. A stress measurement device comprising: a current supply portion; a series circuit which is connected to the current supply portion and has a piezoresistive element that forms a single gauge resistance and a compensating diode that is connected in series to the piezoresistive element; a voltage measuring portion that measures voltage between both ends of the series circuit; a current regulating circuit that has a parallel circuit of a negative current regulating circuit which reduces a current value depending on the increase in temperature, and a positive current regulating circuit which increases the current value depending on the increase in temperature, wherein the single gauge resistance has i) a piezoresistive effect in which a resistance value changes according to applied stress, and ii) a positive temperature characteristic in which the resistance value increases depending on an increase in temperature, wherein the compensating diode is provided in a forward direction with respect to the current supply portion and has a negative temperature characteristic in which a voltage between an anode and a cathode of the compensating diode decreases depending on the increase in temperature, and wherein the piezoresistive element and the current regulating circuit are connected in parallel with the current supply portion.