Detector, physical quantity measuring device, and electronic apparatus
First Claim
1. A detector that detects a detection signal corresponding to a driving vibration, which excites a vibrator in an oscillation loop, and a physical quantity to be measured, the detector comprising:
- an amplifying circuit that amplifies a signal corresponding to the driving vibration and the physical quantity;
a synchronous detection circuit that detects the amplified signal of the amplifying circuit in synchronization with an oscillation signal in the oscillation loop;
an impedance conversion circuit that converts an output impedance of the synchronous detection circuit;
a first low pass filter to which an output signal of the impedance conversion circuit is supplied and which outputs a first detection signal; and
a second low pass filter to which the output signal of the impedance conversion circuit is supplied and which outputs a second detection signal, whereineach of the first and second low pass filters is formed by a switched capacitor filter circuit,a gain of the first low pass filter is different from that of the second low pass filter, andeach of the first and second low pass filters includes;
a first integrator formed by a switched capacitor circuit having a first operational amplifier;
a second integrator which is formed by a switched capacitor circuit having a second operational amplifier and which is connected to an output end of the first integrator;
a feedback capacitor circuit having a third feedback capacitor inserted between an output end of the second integrator and a virtual ground end of the first operational amplifier; and
a fourth feedback capacitor connected in parallel to the feedback capacitor circuit,the first integrator includes;
a first input capacitor circuit connected between an output end of the impedance conversion circuit and the virtual ground end of the first operational amplifier; and
a first feedback capacitor connected between an output end of the first operational amplifier and the virtual ground end of the first operational amplifier, andthe first integrator inputs a voltage difference between the output end of the impedance conversion circuit and the virtual ground end of the first operational amplifier and some charges, which are stored by a plurality of capacitors of the first integrator, to the virtual ground end of the first operational amplifier through a switch, and changes an output potential of the first operational amplifier using the first feedback capacitor, andthe second integrator includes;
a second input capacitor circuit connected between the output end of the first operational amplifier and a virtual ground end of the second operational amplifier; and
a second feedback capacitor connected between an output end of the second operational amplifier and the virtual ground end of the second operational amplifier, andthe second integrator inputs a voltage difference between the output end of the first operational amplifier and the virtual around end of the second operational amplifier and some charges, which are stored by a plurality of capacitors of the second integrator, to the virtual ground end of the second operational amplifier through a switch, and changes an output potential of the second operational amplifier using the second feedback capacitor.
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Accused Products
Abstract
A detector is provided that detects a detection signal corresponding to a driving vibration, which excites a vibrator in an oscillation loop, and a physical quantity to be measured. The detector includes an amplifying circuit, a synchronous detection circuit, an impedance conversion circuit, a first low pass filter, and a second low pass filter, wherein each of the first and second low pass filters is formed by a switched capacitor filter circuit, a gain of the first low pass filter is different from that of the second low pass filter.
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Citations
14 Claims
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1. A detector that detects a detection signal corresponding to a driving vibration, which excites a vibrator in an oscillation loop, and a physical quantity to be measured, the detector comprising:
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an amplifying circuit that amplifies a signal corresponding to the driving vibration and the physical quantity; a synchronous detection circuit that detects the amplified signal of the amplifying circuit in synchronization with an oscillation signal in the oscillation loop; an impedance conversion circuit that converts an output impedance of the synchronous detection circuit; a first low pass filter to which an output signal of the impedance conversion circuit is supplied and which outputs a first detection signal; and a second low pass filter to which the output signal of the impedance conversion circuit is supplied and which outputs a second detection signal, wherein each of the first and second low pass filters is formed by a switched capacitor filter circuit, a gain of the first low pass filter is different from that of the second low pass filter, and each of the first and second low pass filters includes; a first integrator formed by a switched capacitor circuit having a first operational amplifier; a second integrator which is formed by a switched capacitor circuit having a second operational amplifier and which is connected to an output end of the first integrator; a feedback capacitor circuit having a third feedback capacitor inserted between an output end of the second integrator and a virtual ground end of the first operational amplifier; and a fourth feedback capacitor connected in parallel to the feedback capacitor circuit, the first integrator includes; a first input capacitor circuit connected between an output end of the impedance conversion circuit and the virtual ground end of the first operational amplifier; and a first feedback capacitor connected between an output end of the first operational amplifier and the virtual ground end of the first operational amplifier, and the first integrator inputs a voltage difference between the output end of the impedance conversion circuit and the virtual ground end of the first operational amplifier and some charges, which are stored by a plurality of capacitors of the first integrator, to the virtual ground end of the first operational amplifier through a switch, and changes an output potential of the first operational amplifier using the first feedback capacitor, and the second integrator includes; a second input capacitor circuit connected between the output end of the first operational amplifier and a virtual ground end of the second operational amplifier; and a second feedback capacitor connected between an output end of the second operational amplifier and the virtual ground end of the second operational amplifier, and the second integrator inputs a voltage difference between the output end of the first operational amplifier and the virtual around end of the second operational amplifier and some charges, which are stored by a plurality of capacitors of the second integrator, to the virtual ground end of the second operational amplifier through a switch, and changes an output potential of the second operational amplifier using the second feedback capacitor. - View Dependent Claims (11, 12, 13, 14)
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2. A detector that detects a detection signal corresponding to a driving vibration, which excites a vibrator in an oscillation loop, and a physical quantity to be measured, the detector comprising:
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an amplifying circuit that amplifies a signal corresponding to the driving vibration and the physical quantity; a synchronous detection circuit that detects the amplified signal of the amplifying circuit in synchronization with an oscillation signal in the oscillation loop; an impedance conversion circuit that converts an output impedance of the synchronous detection circuit; a first low pass filter to which an output signal of the impedance conversion circuit is supplied and which outputs a first detection signal; and a second low pass filter to which the output signal of the impedance conversion circuit is supplied and which outputs a second detection signal, wherein each of the first and second low pass filters is formed by a switched capacitor filter circuit; a gain of the first low pass filter is different from that of the second low pass filter; a first input capacitor circuit which has a first input capacitor and a second input capacitor, which is set to have the same capacitance value as the first input capacitor, and to which the output signal of the impedance conversion circuit is supplied; a first operational amplifier which amplifies a signal corresponding to an amount of electric charge charged in the first input capacitor circuit; a first integrator having a first feedback capacitor inserted between a virtual ground end and an output end of the first operational amplifier; a second input capacitor circuit which has a third input capacitor and a fourth input capacitor, which is set to have the same capacitance value as the third input capacitor, and which is connected to the output end of the first operational amplifier; a second operational amplifier which amplifies a signal corresponding to an amount of electric charge charged in the second input capacitor circuit; a second integrator having a second feedback capacitor inserted between a virtual ground end and an output end of the second operational amplifier; a feedback capacitor circuit having a third feedback capacitor which is formed so as to be able to be inserted between an output end of the second integrator and the virtual ground end of the first operational amplifier; and a fourth feedback capacitor connected in parallel to the feedback capacitor circuit, the first input capacitor circuit transfers electric charge, which is charged in the second input capacitor in synchronization with a second clock with a phase opposite to a phase of a first clock, to the first input capacitor in synchronization with the first clock and transfers electric charge, which is charged in the first input capacitor, to the first feedback capacitor in synchronization with the second clock, the second input capacitor circuit transfers electric charge, which is charged in the fourth input capacitor in synchronization with the first clock, to the third input capacitor in synchronization with the second clock and transfers electric charge, which is charged in the third input capacitor, to the second feedback capacitor in synchronization with the first clock, and, the feedback capacitor circuit is inserted between the output end of the second integrator and the virtual ground end of the first operational amplifier in synchronization with the first clock, and discharges electric charge, which is charged in the third feedback capacitor, in synchronization with the second clock. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10)
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Specification