Displacement detection device for a portable apparatus
AssigneeSTMicroelectronics S.r.I.
InventorsMichele Tronconi, Enrico Chiesa, Fabio Pasolini
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Abstract
In a displacement detection device, an acceleration sensor generates at least a first acceleration signal relating to an axis of detection, and a displacement detection circuit is connected to the acceleration sensor has a comparator stage for comparing the acceleration signal with a programmable acceleration threshold and generates a displacement-detection signal. A high-pass filter is arranged between the acceleration sensor and the comparator stage so as to reduce a DC component of the acceleration signal. The cut-off frequency of the high-pass filter is modified according to the type of displacements that are to be detected.
Claims31
A displacement detection device, comprising:
- an acceleration sensor generating a first acceleration signal relating to a first axis of detection;
- and
- a displacement detection circuit connected to said acceleration sensor and comprising a first comparator stage for comparing said first acceleration signal with a first acceleration threshold and generating a first displacement detection signal, said displacement detection circuit further comprises first filtering means arranged between said acceleration sensor and said first comparator stage and configured to reduce a DC component of said first acceleration signal.
A method for detection of the displacements of a portable apparatus, comprising:
- detecting at least a first acceleration signal correlated with the acceleration of said portable apparatus along a first axis of detection;
- comparing said first acceleration signal with a first acceleration threshold;
- generating a first displacement-detection signal based on the comparison between said first acceleration signal and said first acceleration threshold;
- and
- attenuating by filtering a DC component of said first acceleration signal before comparing said first acceleration signal with said first acceleration threshold.
A circuit, comprising:
- an input circuit receiving an external acceleration signal and generating therefrom a filtered acceleration signal having a reduced DC component;
- a detection circuit receiving the filtered acceleration signal and further receiving a threshold signal and generating in response thereto a detection signal;
- and
- a microprocessor receiving the detection signal and generating in response thereto an actuation signal.
A circuit for processing an acceleration signal, comprising:
- an input circuit configured to receive an external acceleration signal and to generate a filtered acceleration signal;
- a first threshold signal circuit configured to store and output a first threshold signal;
- a comparator circuit configured to receive the first acceleration signal and the first threshold signal and to output a detection signal;
- and
- an enabling circuit configured to receive the detection signal and an external enabling signal and to generate a logic signal in response thereto.
Dependencies are inferred from the claim text.