TRIMMING CIRCUIT FOR A SENSOR AND TRIMMING METHOD

摘要

An on-board trimming circuit suitable for trimming an accelerometer (100) provides offset trim (112, 113) and gain trim (116, 115) modules for determining correct trim codes for subsequent programming into the trimming circuit. The correct trim codes may be determined by comparing sensor outputs (107,108,109) which have been adjusted by successive trim codes, with a reference voltage in a comparator (117) until the comparator toggles or by using a successive approximation technique. The reference voltage is supplied form a tap (130) of a feedback resistance divider circuit (128) which forms a part of an on-board voltage reference generator (126) which may be used to provide a full scale reference for an analog to digital converter which converts a sensor output voltage into a digital signal. Using reference voltages supplied from such a feedback circuit significantly lessens the impact of any offsets inherent in the voltage reference generator (126) on the trimming process.