Patent ID: 9194895
Filing Date: 2015-11-24
Classification: G01R

Abstract:
1. A power-measurement cell on a silicon substrate with at least one thermo-element and at least two heating elements, wherein a first heating element is heated by a measurement signal, wherein a temperature is measured via the thermo-element, wherein the two heating elements provide a spacing distance, so that a temperature increase in one of the heating elements leads to an approximately equally large temperature increase in all other heating elements and therefore leads to an identical common temperature in all heating elements, wherein the at least one thermo-element and the two heating elements provide a thermal coupling; wherein the heating elements and the at least one thermo-element are arranged on a membrane, wherein the membrane is formed from a lower silicon-oxide layer and an upper silicon layer, and wherein the membrane is formed in a recess in the silicon substrate such that thermal conductivity of the membrane determines measurement accuracy and power-carrying capacity of the power-measurement cell; wherein the at least one thermo-element is directly applied to the upper silicon layer of the membrane to establish an equilibrium temperature and wherein the heating elements are applied to the thermo-element; a verification device coupled to the second heating element, wherein the verification device and power-measurement cell are configured such that (a) a second heating element is supplied with a verification signal of known power by the verification device to verify a calibration of the power-measurement cell; (b) when supplied with the verification signal, the second heating element heats the thermo-element to at least one known temperature; and (c) the verification device is further configured to determine the measurement value of the at least one thermo-element at the at least one known temperature, to record the measurement value, to compare the measurement value with the power of the verification signal to determine compensation values for compensating future measurement values, and to determine if recalibration is necessary.