| 摘要 |
A pseudo-differential accelerometer resistant to EMI is disclosed that includes a device with a sensor core connected to an integrated circuit including a chopper, differential amplifier, and dummy core. The chopper swaps input to output connections during different states. The dummy core is coupled to a dummy chopper input. Three bond wires coupling the sensor output to a sensor chopper input, a first chopper output to a first sensor input, and a second chopper output to a second sensor input can connect the sensor and integrated circuit. The device can include a dummy pad and dummy bond wire connecting the dummy pad to the dummy chopper input. This configuration requires four bond wires connecting the sensor and integrated circuit. A neutralization core can be connected to the sensor chopper input. The chopper can change states to smear noise across a wide range, or away from a band of interest. |
| 主权项 |
1. A pseudo-differential accelerometer resistant to electromagnetic interference, the pseudo-differential accelerometer comprising:
a microelectromechanical device including a capacitive sensor core having a first sensor core input, a second sensor core input and a sensor core output; an integrated circuit including a chopper system, a differential amplifier, a dummy core and a reference voltage, the integrated circuit being coupled to the microelectromechanical device by bond wires;
the differential amplifier including an inverting input, a non-inverting input and producing an amplifier output voltage;the chopper system having a plurality of chopper inputs and a plurality of chopper outputs wherein during a chop state 0 the chopper system connects a first set of the plurality of chopper inputs to a first set of the plurality of chopper outputs and during a chop state 1 the chopper system connects a second set of the plurality of chopper inputs to a second set of the plurality of chopper outputs;the dummy core being coupled to a dummy core chopper input of the chopper system; a sensor core bond wire coupling the sensor core output of the capacitive sensor core to a sensor core chopper input of the chopper system; a first feedback bond wire coupling a first feedback signal to the first sensor core input of the capacitive sensor core, the first feedback bond wire being coupled to a first chopper feedback output; and a second feedback bond wire coupling a second feedback signal to the second sensor core input of the capacitive sensor core, the second feedback bond wire being coupled to a second chopper feedback output; wherein when the chopper system is in the chop state 0 , the chopper system connects the sensor core chopper input to the inverting input of the differential amplifier, connects the dummy core chopper input to the non-inverting input of the differential amplifier, connects the first chopper feedback output to a difference of the amplifier output and reference voltages, connects the second chopper feedback output to a sum of the amplifier output and reference voltages; and when the chopper system is in the chop state 1, the chopper system connects the sensor core chopper input to the non-inverting input of the differential amplifier, connects the dummy, core chopper input to the inverting input of the differential amplifier, connects the first chopper feedback output to the inverse of the difference of the amplifier output and reference voltages, connects the second chopper feedback output to the inverse of the sum of the amplifier output and reference voltages, the inverse of the difference of the amplifier output and reference voltages having the same magnitude and opposite polarity as the difference of the amplifier output and reference voltages, and the inverse of the sum of the amplifier output and reference voltages having the same magnitude and opposite polarity as the sum of the amplifier output and reference voltages. |
