Low power high resolution sensor interface
First Claim
1. A sensor interface circuit for resolving sensor signals from a plurality of sensors into a digital sensor signal, the sensor interface circuit comprising:
- a relaxation oscillator for receiving and pre-processing the sensor signals to generate an analog sensor signal, the relaxation oscillator comprising one or more dynamic circuits; and
a monitoring module for receiving the analog sensor signal and generating the digital sensor signal in response thereto, the monitoring module comprising;
a fixed frequency generation device for generating a clock signal having a fixed frequency of clock pulses; and
a variable window frequency counting device for determining a number of clock pulses within a variable counting window.
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Accused Products
Abstract
A sensor interface circuit is provided for resolving sensor signals from a plurality of sensors into a digital sensor signal. The sensor interface circuit includes a relaxation oscillator that receives and pre-processes the sensor signals to generate an analog sensor signal. The relaxation oscillator includes one or more dynamic circuits. The sensor interface circuit also includes a monitoring module for receiving the analog sensor signal and generating the digital sensor signal in response thereto. There is also provided a sensor system front-end and a relaxation oscillator.
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Citations
18 Claims
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1. A sensor interface circuit for resolving sensor signals from a plurality of sensors into a digital sensor signal, the sensor interface circuit comprising:
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a relaxation oscillator for receiving and pre-processing the sensor signals to generate an analog sensor signal, the relaxation oscillator comprising one or more dynamic circuits; and a monitoring module for receiving the analog sensor signal and generating the digital sensor signal in response thereto, the monitoring module comprising; a fixed frequency generation device for generating a clock signal having a fixed frequency of clock pulses; and a variable window frequency counting device for determining a number of clock pulses within a variable counting window. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A sensor system front-end comprising:
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a plurality of sensors; and a sensor interface for resolving sensor signals from the plurality of sensors into a digital sensor signal, the sensor interface comprising; a relaxation oscillator for receiving and pre-processing the sensor signals to generate an analog sensor signal, the relaxation oscillator comprising one or more dynamic circuits; and a monitoring module for receiving the analog sensor signal and generating the digital sensor signal in response thereto, wherein the monitoring module comprises; a fixed frequency generation device for generating a clock signal having a fixed frequency of clock pulses; and a variable window frequency counting device for determining a number of clock pulses within a variable counting window. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A relaxation oscillator comprising:
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comparators, each having a comparator reference voltage input, a signal input and an output, wherein the comparator reference voltage input of each of the comparators are connected to a comparator reference voltage source; variable capacitors, wherein the number of the variable capacitors is equal to the number of the comparators, and wherein each of the variable capacitors is connected between a ground voltage potential and the signal input of a corresponding one of the comparators and each of the variable capacitors is controlled to reduce its discharging capacitance only when its capacitor voltage approximates a voltage of the comparator reference voltage source; discharge circuits respectively coupled to the variable capacitors, each of the discharge circuits coupled to the respective variable capacitor is coupled to the ground voltage potential and an oscillator output, the discharge circuits are configured to increase a discharge current for the variable capacitors only when a voltage of the variable capacitors approximates the voltage of the comparator reference voltage source; an oscillator input section for receiving a sensor input from a plurality of sensors and providing the sensor input to each of the signal inputs of the comparators; and a frequency generation circuit coupled to the output of the comparators and to the oscillator input section for generating an analog signal from the sensor input for provision to an oscillator output of the frequency generation circuit by controlling provision of the sensor input to the signal inputs of the comparators.
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Specification