Apparatus for Sensor with Programmable Gain and Dynamic Range and Associated Methods

Abstract

An apparatus includes a coil suspended in a magnetic field and an optical detector to detect displacement of the coil in response to a stimulus. The apparatus further includes a feedback circuit to program a gain of the sensor, wherein the feedback circuit is coupled to the optical detector and to the coil.

1 . An apparatus, comprising:
 a coil suspended in a magnetic field;   an optical detector to detect displacement of the coil in response to a stimulus; and   a feedback circuit to program a gain of the sensor, wherein the feedback circuit is coupled to the optical detector and to the coil.   
     
     
         2 . The apparatus according to  claim 1 , wherein the feedback circuit varies the gain of the sensor in response to an output signal of the sensor. 
     
     
         3 . The apparatus according to  claim 1 , wherein the feedback circuit includes a feedback network with a nonlinear transfer function. 
     
     
         4 . The apparatus according to  claim 2 , wherein the nonlinear transfer function comprises a piecewise-linear transfer function. 
     
     
         5 . The apparatus according to  claim 4 , wherein the piecewise-linear transfer function comprises a first linear portion having a first slope corresponding to a first gain value, and a second linear portion having a second slope corresponding to a second gain value, wherein the first slope is larger than the second slope. 
     
     
         6 . The apparatus according to  claim 5 , wherein the gain of the sensor is varied by using the first gain or the second gain depending on an output signal of the sensor. 
     
     
         7 . The apparatus according to  claim 1 , wherein the feedback circuit includes a plurality of feedback networks with a corresponding plurality of nonlinear transfer functions, and wherein the gain of the sensor is programmed by selecting a feedback network from the plurality of feedback networks. 
     
     
         8 . The apparatus according to  claim 7 , wherein at least one of the plurality of nonlinear transfer functions comprises a piecewise-linear transfer function. 
     
     
         9 . The apparatus according to  claim 7 , wherein the feedback circuit varies the gain of the sensor in response to an output signal of the sensor. 
     
     
         10 . The apparatus according to  claim 1 , wherein the gain of the sensor is programmed by changing a resistance of at least one resistor in the feedback circuit. 
     
     
         11 . A method of operating a sensor that includes a coil suspended in a magnetic field and an optical detector to detect displacement of the coil in response to a stimulus, the method comprising programming a gain of the sensor by using a feedback circuit that is coupled to the optical detector and to the coil. 
     
     
         12 . The method according to  claim 11 , wherein programming a gain of the sensor further comprises varying the gain of the sensor in response to an output signal of the sensor. 
     
     
         13 . The method according to  claim 11 , wherein the feedback circuit includes a feedback network with a nonlinear transfer function. 
     
     
         14 . The method according to  claim 13 , wherein the nonlinear transfer function comprises a piecewise-linear transfer function. 
     
     
         15 . The method according to  claim 14 , wherein the piecewise-linear transfer function comprises a first linear portion having a first slope corresponding to a first gain value, and a second linear portion having a second slope corresponding to a second gain value, wherein the first slope is larger than the second slope. 
     
     
         16 . The method according to  claim 11 , wherein programming the gain of the sensor further comprises using the first gain or the second gain depending on an output signal of the sensor. 
     
     
         17 . A sensor, comprising:
 a magnet, having an associated magnetic field;   a coil suspended by a spring in the magnetic field of the magnet;   an optical detector to detect displacement of the coil in response to a stimulus applied to the sensor; and   a feedback circuit coupled to the optical detector and to the coil, the feedback circuit to program a gain of the sensor by using at least one nonlinear transfer function.   
     
     
         18 . The sensor according to  claim 17 , wherein the stimulus comprises acceleration. 
     
     
         19 . The sensor according to  claim 17 , wherein the at least one nonlinear transfer function comprises a piecewise-linear transfer function comprising a first linear portion having a first slope corresponding to a first sensor gain, and a second linear portion having a second slope corresponding to a second sensor gain, wherein the first sensor gain is larger than the second sensor gain. 
     
     
         20 . The sensor according to  claim 17 , wherein depending on an output signal of the sensor a microcontroller unit (MCU) programs the gain of the sensor by causing the feedback circuit to use the first linear portion or the second linear portion of the at least one nonlinear transfer function.