Continuous-time sensing apparatus
AssigneeInvenSense, Inc.
InventorsDu CHEN, Vadim TSINKER, Stanley Bo-Ting WANG
Life of this patent
Estimating the term…
Abstract
A system includes a sensor device, a circuit driving he sensor device at a drive frequency, a receiver, and a low pass filter. The sensor device is configured to change its electrical characteristics in response to external stimuli. The sensor device generates a modulated signal proportional to the external stimuli. The receiver is configured to receive the modulated signal and further configured to demodulate the modulated signal to generate a demodulated signal. The demodulation signal has a guard band. The receiver consumes power responsive to receiving the modulated signal. The low pass filter is configured to receive the demodulated signal and further configured to generate a sensor output.
Claims22
An apparatus comprising:
- a sensor device configured to change its electrical characteristics in response to external stimuli;
- a circuit driving the sensor device at a drive frequency, wherein the sensor device generates a modulated signal proportional to the external stimuli;
- a receiver configured to receive the modulated signal and further configured to demodulate the modulated signal to generate a demodulated signal, wherein a demodulation signal used to demodulate the modulated signal has a guard band;
- and
- a low pass filter configured to receive the demodulated signal and further configured to generate a sensor output.
An apparatus comprising:
- a sensing capacitor of a sensing device configured to generate electrical charges in response to external stimuli, wherein the sensing device is driven at a drive frequency, and wherein the sensing device generates a modulated signal proportional to the external stimuli;
- an amplifier coupled to the sensing capacitor, wherein the amplifier receives the modulated signal and wherein the amplifier is configured to convert the modulated signal into a voltage signal;
- a demodulator configured to demodulate the voltage signal to generate a demodulated signal, wherein a demodulation signal used to demodulate the modulated signal has a guard band, and wherein the amplifier consumes power responsive to receiving the modulated signal;
- and
- a low pass filter configured to receive the demodulated signal and further configured to generate a sensor output.
A method comprising:
- changing a capacitance associated with a sensor responsive to an external stimulus;
- driving the capacitance associated with the sensor;
- generating a modulated electrical signal responsive to the driving;
- demodulating the modulated signal to generate a demodulated signal, wherein a modulation signal used to generate the modulated electrical signal is different from a demodulation signal used to generate the demodulated signal;
- and
- converting the demodulated signal to a digital signal, wherein a frequency associated with converting the demodulated signal to the digital signal is decoupled from a drive frequency of the sensor device.
Dependencies are inferred from the claim text.