Patent ID: 6718275
Filing Date: 2004-04-06
Classification: G01D

Abstract:
A trimming circuit for a physical quantity sensor comprising:an analog circuit for effecting at least one of an adjustment operation of a supply voltage to said physical quantity sensor and a trimming operation for an output voltage of said physical quantity sensor in accordance with a trimming value; a trimming value control circuit having a memory circuit for storing data and generating said trimming value in accordance with said data from said memory; a trimming signal input terminal for inputting a control signal, which include a clock signal, a reset signal, and said data as components; a signal separation circuit for separating said clock signal, said reset signal, and said data from said control signal; a logic circuit, which responds to said clock signal and said reset signal, for supplying said data from said signal separation circuit to said trimming value control circuit and for receiving said data from said trimming value control circuit; a power supply terminal for inputting a driving voltage for said physical quantity sensor; a ground terminal; an output terminal for outputting a voltage signal corresponding to an output of said physical quantity sensor, wherein said trimming circuit has only four terminals; a voltage generation means for generating a predetermined voltage level signal, the level of which is determined on the basis of said data from said logic circuit; and a switch response to said data for outputting either of said voltage signal or said predetermined voltage level signal, wherein said predetermined voltage level signal is distinguishable from said voltage signal.